Alumni-News Alumni of Department of Physics, Cochin University Volume 2, October 2009

PHYSICS/ Alumni-News Alumni of Department of Physics, Cochin University Volume 2, October 2009

Editorial

Editorial Advisory Board Dear all, we are very happy to bring out the second volume of the Alumni News bulletin. This volume too is materi- Alumni President Prof. M.R. Anantharaman alised with the help from all of you. One point to be noted Vice-President Prof. V.C. Kuriakose with pride is that our alumni activities in fact inspired the Secretary Dr. M.K. Jayaraj university community in thinking of an alumni for the en- Editors Dr. Titus K. Mathew tire university. That itself shows our importance and re- Dr. K.J. Saji sponsibility. We still have to go a long way. Our routine activities went smoothly this year also. Let us join hands for the upcoming new activities. We have to appreciate the contribution of our people towards alumni activities, especially Dr. M.K. Jayaraj and his students. We are thanking all who have contributed articles to this volume. Expecting your cooperation in future too. Hello friends...... Regards Please forward your suggestions and contribu- Dr. Titus K. Mathew tions to coming volumes of alumni newsletter to Dr. K.J. Saji [email protected]

CUSAT ranks 3rd among Indian Universities

CUSAT ranks 3 among Indian Universities in the ranking of all Indian engineering and technology in- K.J. Saji stitutes for their research performance in a study conducted by Dr. Gangan Prathap and B. M. Gupta. Authors used SCOPUS database p-index for rank- [email protected]

Contents of this volume: Novel holographic recording material . . . . .8 Dark Energy - The challenge of the millen- Editorial ...... 1 nium ...... 9 rd CUSAT ranks 3 among Indian Universities .1 Student Activities ...... 11 Nobel Prize in Physics 2009 ...... 2 Dr. L.Godfrey CUSAT Pro-Vice Chancellor . . 13 Congratulations Dr. V. Ramakrishnan . . . . .2 Tokamak Plasma: Realization of Fusion Energy3 Raveendranath - some reminiscences ...... 13 International Year of Astronomy: 2009 . . . . .4 ECS Interface Tech Highlights ...... 14 Amorphous and nanocrystalline thin films for SIMS research award to Aneesh ...... 14 soft magnetic applications ...... 6 Recent Ph.D. award and thesis submission . . 14 PHYSICS/Alumni-News Vol. 2, October 2009 ing Indian universities and institutes. A total of 67 Science, Pilani (18.33); Bengal Engineering and Sci- Indian engineering and technological institutes with ence University, Howrah (12.44); Jawaharlal Nehru comparatively higher output of publications during Technological University, Hyderabad (10.20) etc. a ten-year period from 1999 to 2008 were identified. CUSAT ranks 10, among all Indian engineering IISc and the IITs lead the list among all engineering and technology institutes including IISc and IITs, and technological institutes in the country. Among considreing total number of research papers pub- the universities, the best performance in terms of p- lished during the period 1999 to 2008. Combining index values (30.30) is shown by Jadavpur Univer- quantity and quality of research papers, CUSAT has sity, Kolkata, followed by Anna University, Chennai 11th position in the list. (24.54); Cochin University of Science and Technol- CUSAT is the only university from Kerala which ogy, Cochin (18.67); Birla Institute of Technology and find its slot in this ranking. (Source: CURRENT SCIENCE, VOL. 97, NO. 3, 10 AUGUST 2009)

Nobel Prize in Physics 2009 Prize in physics. Charles Kao was honored for his research that led to the transmission of light through optic fibers which facilitate the global broadband communications. According to No- bel physics committee chairman Joseph Nordgren "He de- vised a pathway to obtain the low-loss fibers that were needed in order to communicate over long distances and this led to successful fabrication of such fibers a few years later". Willard Boyle and George Smith was awarded for the Charles Kao, Willard Boyle and George Smith invention of CCD sensors. Charge-coupled device (CCD)allows an electronic recording of images and it re- Three pioneers in optoelectronics, Charles Kao, places the photographic film in cameras and other imaging Willard Boyle and George Smith, share this year’s Nobel devices.

Congratulations Dr. V. Ramakrishnan Dr. Venkatraman Ramakrishnan shares this year’s Nobel Prize in chemistry for his studies of the structure and function of the ribosome. He is the seventh Indian or of Indian origin to win the prestigious Nobel Prize. He was born in Tamilnadu and earned his B.Sc. in Physics from M S University in Baroda, and Ph.D in Physics from Ohio University in the US. Presently, Dr. Ramakrishnan is a senior scientist at the MRC Laboratory of Molecular Biology in Cambridge.

Dr. Venkatraman Ramakrishnan; molecular model of a bacterial ribosome (right side image)

c Department of Physics,CUSAT 2 PHYSICS/Alumni-News Vol. 2, October 2009

Tokamak Plasma: Realization of Fusion Energy

ment) based magnetic confinement fusion. Toka- maks provide today the most credible design for a Dr. N.V. Joshy future fusion reactor and International Thermonu- clear Experimental Reactor (ITER) is also being built Human society is faced with a precarious situation of on this principle. Tokamaks were originally discov- increasing energy demands, especially from growing ered in the erstwhile Soviet Union (hence the Rus- third world economies like India and China. This sian acronym), but later tokamak based fusion ex- is due to the fast depleting conventional energy re- periments across the globe produced very promising sources which have been dominated by fossil fuel in results. Energy released through fusion reactions the past century. The difference between the demand also has many advantages over nuclear fission en- and the available supply has already started widen- ergy. It does not release any Greenhouse gases or ing. This can potentially lead to conflicts of human radioactive waste unlike a fission reaction. societies which can become a serious problem unless a viable extractable alternative energy resource(s) is not obtained.

Indian Scenario India is presently the fourth largest electricity producing country in the world. India’s per capita energy consumption (500 kWh) is rather small. This is only about 1/2 of China, 1/4th of World average and about 1/13th of developed nations. However, India aspires to reach at least the global average by 2050, which would require her to produce about 1300 GW of electricity, ten times more than the present value of about 130 GW. Of the present electricity generation, about 80% of the resources are fossil fuels, Hydro Tokamak configuration about 15%, renewable about 2% and nuclear about 3%. Courtesy: European Nuclear Society Relying on fossil fuels alone to increase the en- The toroidal and poloidal field magnets as well ergy production is both impractical and impossi- as current in the plasma produce the main magnetic ble. This is mainly because of lack of access to re- field. quired resources. Even if resources are available, it would produce irreparable damage to the environment through global warming. The conventional nu- Role of India in tokamak project clear power production based on fission reactions is The importance of the quest for a nuclear fusion re- slated to grow to about 20% of the total by 2050. actor can be gauged from the fact that seven coun- To meet the energy demand in coming decades, it tries, including India, have pooled their resources to is essential to find alternate resources. Thus fusion, build an International Thermonuclear Experimental which can be viewed as an advance nuclear technol- Reactor (ITER) device at Cadarache in France at an ogy, provides a great opportunity to India to meet the estimated cost of 5 billion euros. The other partners energy needs. in the project are the US, the EU, Russia, Japan, South Korea and China. The ITER will be the largest toka- Tokamak mak when built which is yet to take some more time. The Institute of Plasma Research (IPR), Gandhinagar, The tokamak becomes important in the light of the which comes under the Department of Atomic En- elusive quest for producing electricity through sus- ergy, is the nodal institution in the country and part tained nuclear fusion. The most significant achieve- of the ITER project. ments in fusion experiments so far have been in Incidentally, the IPR has an existing tokamak, tokamak ( toroidal chamber for magnetic confine- ’Adiyta’, built in 1989. The Steady State Tokamak

c Department of Physics,CUSAT 3 PHYSICS/Alumni-News Vol. 2, October 2009

(SST-1) is now in the ﬁnal stages of manufacture. The improve the transmission characteristics of tokamak SST-1 was conceptualised in 1994 and is expected to windows. The cleaning can very effectively be per- take around few years more before it can be commis- formed by laser-etching. The applicability of Q- sioned. A nuclear fusion reactor is still a long way switched Nd:YAG laser for the cleaning from the ahead, but scientists are hoping that the SST-1 will rear side of the optical window is being investigated. play its own small but important part in that journey. The effective laser wavelength, threshold laser ﬂu- ence and irradiation time have to be determined for Input from CUSAT the type and thickness of material deposited. Also some very precise two dimensional sweeping ar- Investigations to improve the optical transmission rangements for the laser beam is required so as to characteristics of tokamak windows are being car- have the irradiation of all points of the optical win- ried out in the physics department under the su- dow of the tokamak at the optimized laser parame- pervision of Dr. M.K.Jayaraj, in collaboration with ters. IPR. Transmission of optical windows in tokamak gets severely attenuated by the deposition of impu- Lecturer rity particles like C and Fe from plasma. There- St. Paul’s College, Kalamassery fore the cleaning of optical windows is essential to [email protected]

International Year of Astronomy: 2009

Brahe’s astronomical observations of planets over several years. Other examples include the discovery Vivek M of Helium and achievements in particle physics. In this sense, Astronomy indeed has played an important role in the evolution of mankind. We all know that we are on a It continues to make a profound impact on our cul- tiny blue planet orbiting an av- ture and is a powerful expression of the human in- erage star. This average star tellect. Huge progress has been made in the last few is located slightly over half decades. One hundred years ago we barely knew way out from the center of our of the existence of our own Milky Way. Today we galaxy, Milky Way. There are know that many billions of galaxies make up our over 200 billion stars in the Universe and that it originated approximately 13.7 Milky Way and ours is only a billion years ago. One hundred years ago we had typical galaxy among billions of no means of knowing whether there were other so- galaxies in the observable uni- lar systems in the Universe. Today we know of more verse. Given this, you might be than 200 planets around other stars in our galaxy and tempted to ask yourself,“Where we are moving towards an understanding of how life did it all come from, where is it might have ﬁrst appeared. One hundred years ago all going and where do I ﬁt into it we studied the sky using only optical telescopes and all?”. This is exactly what As- photographic plates. Today we observe the Universe tronomy is trying to answer. from Earth and from space using cutting edge tech- There exists a very popular misconception about as- nology. Media and public interest in astronomy have tronomy among the people. It is often argued that as- never been higher and major discoveries are front- tronomy deals with remote and esoteric objects like page news throughout the world. stars and galaxies very, very far away and so its studies are irrelevant to mankind. But, one can contradict the argument by saying that it was infact astronomy that really started the revolution that we today iden- tify with information technology. The reasoning is that the present day achievements in communication technologies are based on satellite communications which in turn is based on Newton’s law of gravita- tion. Newton could derive his law because he had Kepler’s law of planetary motion as the base data. Kepler arrived at his equations by analysing Tycho

c Department of Physics,CUSAT 4 PHYSICS/Alumni-News Vol. 2, October 2009

4. Support and improve formal and informal science education in schools.

5. Provide a modern image of science and scientists to reinforce the links between science education and science careers, and thereby stimu- late a long-term increase in student enrolment in the ﬁelds of science and technology, and an appreciation for lifelong learning.

6. Facilitate new networks and strengthen existing ones by connecting amateur astronomers, educators, scientists and communication pro- Images taken with IRC 6" telescope on 29th April 2009 fessionals through local, regional, national and international activities. Year 2009 is being celebrated world wide as the International Year of Astronomy(IYA). This is a 7. Improve the gender-balanced representation of global effort initiated by the International Astronom- scientists at all levels and promote greater in- ical Union (IAU) and UNESCO to help the citizens volvement by underrepresented minorities in of the world to rediscover their place in the Universe scientific and engineering careers. through the day- and night-time sky, and thereby en- gage a personal sense of wonder and discovery. Year 8. Facilitate the preservation and protection of the 2009 coincides with the 400th anniversary of the first world’s cultural and natural heritage of dark recorded astronomical observations with a telescope skies in places such as urban oases, national by Galileo Galilei and the publication of Johannes parks and astronomical sites. Kepler’s Astronomia nova. IYA2009 activities are taking place at global and re- Considering that Galileo wasn’t the person who in- gional levels. The global network has now reached vented the telescope, it is interesting to ask what was 137 countries making it possible to reach out for 97 the importance of his telescope and observations. % of world population. National nodes have been Before Galileo’s telescope came along, nobody had formed in each countries to coordinate the activities. ever thought to use the device to look at the stars. Here in India , there are several academic and non- With this simple telescope he observed the Moon, academic organizations which are regularly con- discovered four satellites of Jupiter, resolved nebu- ducting astronomy popularization programs such as lar patches into stars and even studied sunspots. It workshops, lecture series, sky watch demonstrations was Galileo who made astounding discoveries that etc. as a part of IYA activities. India itself hosts over changed humankind’s understanding of our posi- two hundred scientists who are pursuing front-line tion in the universe. research in Astronomy and Astrophysics in several research institutes and universities. IYA2009 envisages to create an awareness about the impact of astronomy and other fundamental sciences on our daily lives. It aims to make the people under- IYA Activities at Physics Department, CUSAT stand how scientific knowledge can contribute to a IYA activities at the Physics department was inau- more equitable and peaceful society. The major goals gurated by Prof. Ajit Kembhavi on 6th March 2009. of IYA2009 have been identified by IAU as follows: All the programmes are being done in collaboration with IUCAA Reference Cente. Observing through 1. Increase scientific awareness among general a telescope for the first time is a unique experience public and school children through communi- that shapes our view of the sky and Universe. Real- cation of scientific results in astronomy and re- izing that a do-it-yourself Galileoscope could be the lated fields. key to pursuing an interest in astronomy even beyond IYA2009,we are promoting everyone to make 2. Promote widespread access to universal their own affordable telescope which is simple, ac- knowledge of fundamental science through cessible, easy-to-assemble and easy-to-use. This sim- excitement of astronomy and sky observing ple telescope enables one to build and observe with experiences. a telescope that is similar to Galileo’s. Our major IYA programes include, 3. Empower astronomical communities in developing countries through initiation of interna- 1. A Two-days Seminar on ’Astronomy, gravity tional collaborations. & beyond Einstein’ was conducted on March

c Department of Physics,CUSAT 5 PHYSICS/Alumni-News Vol. 2, October 2009

6 and 7, 2009. The speakers include Prof. for the public at the department,whenever the Ajit Kembhavi & Prof. Ranjeev Misra from sky is clear,. We use a 6 inch reﬂecting tele- IUCAA,Pune, Prof. T. R. Govindarajan from scope to show several astronomical objects like IMSc, Chennai, Prof. V.C. Kuriakose from moon, Jupiter and its four satellites, Saturn, CUSAT and Dr. C.D. Ravikumar from Calicut Venus, Mars and several nebulae and star clus- University. ters. 2. A workshop on "Making small telescopes" was conducted for the students participating in the ten day Summer programme "Physics: Scope & Awareness" conducted by the department of Physics during 20-30th April 2009. Nearly 45 high school students from nearby schools participated in the program. Mr. Arvind Paranj- pay from IUCAA guided the students in making a 2 inch telescope and a CD/DVD spectro- scope. 3. We have drawn a new programme to visit schools to demonstrate to the students and teachers of making small telescopes and to tell Telescope making class them the importance of astronomy and science in general. The telescope is a 2 inch refractor In the near future, we plan to extend our school with 20x magniﬁcation. Typically a school visit visits to many more schools and to have several pub- has an introductory talk on astronomy, hands- lic outreach programmes to highlight different as- on session of making small telescopes, a talk on pects of astronomy in a manner accessible to the lay observing night sky using sky charts followed public. by real sky watching using a 6 inch IRC telescope. Till now, we have visited 4 schools in Senior Research Fellow and around Ernakulam district. Dept. of Physics, CUSAT 4. We conduct regular sky watching programmes [email protected]

Amorphous and nanocrystalline thin ﬁlms for soft magnetic applications

resistance and the emergence of spintronics are all a testimony to this fact. Senoy Thomas Properties of magnetic materials range widely, from hard magnetic to soft magnetic and insulating Magnetic materials have been playing an important to metallic. Materials with excellent soft magnetic role in the day-to-day life of human beings from the properties are extensively used in power transform- time lodestone was discovered. They form part of ers, sensors and magnetic shielding devices. Most of many devices and the ﬁeld of magnetism today pro- the soft magnetic applications in the past were based vides the world’s second largest industry, with mag- on crystalline magnetic materials. However, the netic materials claiming a market share next to semi- newest addition to the class of soft magnetic mate- conductor industry. In the current scenario, the de- rials is not crystalline, but amorphous and nanocrys- mand for magnetic material is fast rising and mag- talline. netism has taken a central stage in science and tech- Amorphous magnets were ﬁrst fabricated in nology. Even more excitingly, several exotic mag- 1967 from their liquid states by means of a rapid- netic phenomenon and novel materials have recently quenching technique. A variety of alloy composi- been discovered, many of which seem to hold the vi- tion has been prepared by employing this technique, tal keys in unlocking fascinating as well as challeng- where the melt is rapidly cooled at a rate of ∼ 104 ing physics. The recent discovery of giant magneto K/s to get an amorphous solid. The tremendous ad-

c Department of Physics,CUSAT 6 PHYSICS/Alumni-News Vol. 2, October 2009 vances made in this field during a short span of time NEMS etc. This not only allows the miniaturiza- have led to the further discovery of new magnetic tion of the sensor elements, but also enables the same materials and new phenomenon which in turn re- micro-fabrication technologies to be used in both the sulted in newer applications of the materials. The production of the electronic and the magnetic de- subject is now a hot topic of research in solid state vices. The integration of magnetic components into physics and is of interest to physicists, materials sci- MEMS (MagMEMS) offers the advantages of imple- entists and electrical and electronics engineers. menting wireless technology. In comparison with Nanocrystalline magnetic materials have been other MEMS technologies, for example those incor- known for over twenty years since the discovery porating piezoelectric materials, MagMEMS offer a of FINEMET@TM by Yoshizawa and coworkers in high power density, low performance degradation, 1988 (Yoshizawa et al. 1988 J Appl Phys. 64 6044). fast response times and ease of fabrication. However, it is only the recent developments in com- It should also be noted that the spectrum of acces- plex alloys and their metastable amorphous pre- sible amorphous and nanocrystalline systems can be cursors which revolutionized the field of soft mag- expanded by thin film preparation techniques. One netism. Nanoscience and Nanotechnology is lead- example is Hf carbide dispersed nanocrystalline Fe- ing this revolution fueled by the industrial progress, Hf-C films crystallized from the amorphous state. the scientific ability to fabricate, model and manip- They combine good thermal stability, good high fre- ulate nano magnetic materials, and the almost daily quency properties in the MHz range with low mag- discovery of new phenomena in nanoscale magnetic netostriction and high saturation induction of Js=1.7 materials. T which can be even increased up to 2 T by multi- Nanocrystalline magnetic materials are com- layering these films with Fe. Another example are monly produced by the partial crystallization of its (Fe,Co,Ni)-(Si,B)-(F,O,N) granular alloy films which amorphous precursors. The microstructure of these at a saturation induction of about 1 T possess a materials consists of nano sized ferromagnetic mate- uniquely high electrical resistivity of 103-104 µΩcm rials embedded in an amorphous matrix. The ma- which makes them a possible candidate for high fre- trix phase must also be ferromagnetic for facilitat- quency devices. ing the exchange coupling between the nanoparti- 2.0 cles. As a result of this coupling, they often exhibit 1.5 vanishing magneto-crystalline anisotropy. Since the 1.0 ) soft magnetic properties are strongly related to the u

m 0.5 e

crystalline anisotropy, the exchange interaction in 3 - nanocrystalline magnetic materials results in low co- 0 0.0

1 x (

ercivity and high permeability. Interesting properties t -0.5 n e of nanocrystalline magnetic materials are a conse- -1.0 m quence of the effects induced by the nanocrystalline o

M -1.5 structure. They include interface physics, the influ- ence of the grain boundaries, the averaging of mag- -2.0 netic anisotropy by exchange interactions, the de- -2000 -1000 0 1000 2000 H (Oe) crease in exchange length, and the existence of a min- imum two-phase structure in such materials. Room temperature hysteresis for Fe-Ni films There has been extensive research in amorphous and nanocrystalline materials in melt-spun ribbon Recently we, the Magnetics group in the depart- form, which exhibit excellent magnetic properties ment of physics, CUSAT in collaboration with NTU, i.e., large saturation magnetostriction, high satu- Singapore and SQU, Muscat reported the prepara- ration magnetization and low anisotropy energies. tion of amorphous and nanocrystalline Fe-Ni thin These factors have made soft magnetic ribbon ma- films using a simple thermal evaporation technique terials excellent candidates for sensors and actuator (S. Thomas et al 2008 J. Phys. D: Appl. Phys. devices. At present these alloys are available only in 41 155009). The room temperature hysteresis loop the form of ribbons of thickness ranging from 10 to recorded for these films (see figure 1) implies the po- 50 micron. A series of post treatment process such as tential application of these films for soft magnetic ap- high temperature annealing and epoxy treatment are plication. further required for amorphous alloy ribbons to be Further as prepared amorphous thin films exhib- used as sensors. Therefore there are many difficul- ited excellent magnetostriction properties which are ties in the micro sensor application. Consequently, promising for miniaturizing sensors and integrating materials in the form of thin films have to be de- these magnetic thin films to MEMS, NEMS etc. The veloped for the miniaturization of sensors as well advancement in thin film magnetism is also expected as for integrating magnetic components to MEMS, to deliver thin film transformers which will replace

c Department of Physics,CUSAT 7 PHYSICS/Alumni-News Vol. 2, October 2009 the bulky transformers used in present day electron- Senior Research Fellow ics and result in further miniaturization of electronic Dept. of Physics appliances. [email protected]

Novel holographic recording material

Pramitha V

Transmission holograms recorded using different lasers

Holography plays an essen-

front_cover.qxd 4/22/09 8:46 AM Page 1 tial role in today’s science and

ISSN: 0003-6935 Applied Optics industry. Relevant applications making use of its principle have been developed, including three-dimensional (3D) displays and holographic cameras, interferometers for non- destructive material analysis, 20 April 2009 data storage systems, diffrac- white light hologram tive optical systems and em- bossed display holograms for Though several research groups and industries in security features. Holographic data storage has been the world are trying to develop highly efficient pho- considered as a promising data storage technology topolymer recording media, the lack of commercial since 1960s because of its outstanding characteristics availability of the plates in India is a major issue. In such as parallel storage and retrieval, high density this context, indigenous development of photopoly- storage and fast data transfer rates. Developing ap- mer systems that satisfies the media requirements propriate recording media is critical in achieving a for both display and storage applications has great practical holographic storage system. Recently, great significance. Research work in Applied Optics Divi- advances have been made in the use of photopoly- sion is mainly focused on the development of highly mers as holographic recording medium. Compared efficient polymer based holographic recording me- with conventional holographic recording materials dia. Poly (vinyl alcohol) (PVA) based photopoly- such as dichromated gelatin and silver halide emul- mer recording media with different film composi- sions, photopolymers have the great advantage of tions could be successfully developed. Films were recording and reading holograms in real time and fabricated using gravity settling method and by spin the spectral sensitivity could be easily shifted to the coating. He-Ne (632.8 nm), Nd-YAG (532 nm) and type of recording laser used by simply changing the Ar+ ion (488 nm) lasers were used for characteriza- sensitizing dye. Of the different photopolymeriz- tion of the films. Various chemical and physical pa- able compositions, Poly (vinyl alcohol)-acrylamide rameters were optimized so as to obtain high diffrac- based photopolymers have been widely studied tion efficiency, sensitivity, storage life etc. Major due to their excellent properties like high sensitiv- research achievements include development of red ity, high diffraction efficiency (DE), large dynamic sensitive material with 80% efficiency, panchromatic range (M/]) and real time capabilities. recording material with more than 70% efficiency, permanent red sensitive material with good storage

c Department of Physics,CUSAT 8 PHYSICS/Alumni-News Vol. 2, October 2009 life, red sensitive material showing self enhancement nm) was the cover image of the journal. Silver doped of efficiency, reusable recording medium, blue sen- photopolymer films showed good energy sensitiv- sitive material with 70% efficiency and so on. The ity, high diffraction efficiency, good storage and shelf potential of the developed photopolymer films for lives. All the developed materials are highly eco- holographic data storage applications is also stud- nomic and require no wet post processing technique. ied using different multiplexing techniques. Holo- The funding by Defence Research and Development graphic lens with high efficiency was recorded in the Organization (DRDO), Department of science and films. Bright transmission holograms and white light Technology (DST) and Kerala State Council for Sci- holograms were also successfully recorded in the ence Technology and Environment (KSCSTE) sup- materials. Studies on the development and charac- ports the work on these materials. terization of silver doped photopolymer media was recently published in the prestigious OSA journal "Applied Optics" (Vol. 48, No. 12, 2255-2261, April Senior Research Fellow 2009). Photograph of bright transmission hologram Dept. of Physics recorded in this material using He-Ne laser (632.8 [email protected]

Dark Energy - The challenge of the millennium

general relativity, is to add a cosmological constant (CC) term to the Einstein equations. Before Edwin Titus K. Mathew Hubble discovered the expansion of the universe, Al- bert Einstein had originally introduced such a term [email protected] to obtain a static solution of his cosmological equations. After the cosmic expansion was discovered, Einstein considered his introduction of the CC to be Introduction the greatest mistake of his career. Another possibility is he inclusion of dark energy, in the total energy In 1998, two teams studying distant type Ia super- density of the universe. novae (SNe Ia) independently presented evidence Observations of the dynamics of galaxies and that the expansion of the universe is accelerating up clusters have shown that the amount of matter is (Riess et al. 1998, Perlmutter et al. 1999). Since short of the critical density (density required for a Hubble, cosmologists had been trying to measure flat universe). At the same time observations of the slowing of the expansion due to gravity by ob- temperature anisotropies in the cosmic microwave serving the deceleration parameter ( parameter used background are consistent with a nearly flat universe to quantify the second derivative of the expansion, Ωtotla ≈ 1. Hence it may be possible to infer the ex- q0,)(Sandage 1962). The discovery of cosmic acceler- istence of a dark energy component ρdark smoothly ation is arguably one of the most important develop- distributed through out space, so it doesn’t influ- ments in modern cosmology. ence the local motions of galaxies and clusters, with The physical origin of cosmic acceleration re- Ωtotal ≈ 0.7. mains a deep mystery. According to General Relativ- The task of discovering the nature of the dark en- ity (GR), if the Universe is filled with ordinary mat- ergy" is of obvious importance to cosmology. The ap- ter or radiation, the two known constituents of the parent acceleration of the expansion of the universe Universe, gravity should lead to a slowing of the ex- is attributed to a dark energy residing in space itself, pansion. Since the expansion is speeding up, we are which also balances the kinetic energy of the expan- faced with two possibilities,. The first is that 75% of sion so as to give the universe zero spatial curvature, the energy density of the Universe exists in a new as observed in mapping fluctuations in the cosmic form with large negative pressure, called dark en- microwave radiation background. If the dark energy ergy. The other possibility is that General Relativity is a constant (the so-called cosmological constant) or breaks down on cosmological scales and must be re- growing then the fate of the universe is sealed: it placed with a more complete theory of gravity. The will continue expanding forever. If the dark energy is simplest way to incorporate that acceleration into the decreasing (as in some "quintessence" theories) then description of cosmology, within the framework of it was even more important in the past, and may

c Department of Physics,CUSAT 9 PHYSICS/Alumni-News Vol. 2, October 2009 have played a part in limiting the formation of the and slowly varying in time, it is not perfectly a con- largest gravitationally bound structures. In any case, stant. One of the possibilities is a kind of source typ- through its effect on the expansion of the universe, ically like a scalar ﬁeld rolling slowly in potential, the dark energy affects all observations of astronom- some times known as "quintessence". But the need ical objects at large red-shift. for delicate ﬁne tunings of masses and coupling con- stants is seems to be drawback of these type of mod- els. Cosmological Constant

This is a straight forward candidate for dark energy that may vary slowly in both space and time. The Modified theories of gravity. special feature of dark energy is that, it is a mini- mum amount of energy density in any region and In Newton’s theory mass is the source of gravita- constant through out space-time. To match the accel- tional field and the gravity is always attractive. In erated expansion data, the required vacuum energy general relativity noth energy and pressure are the 4 source of gravity. So a sufficiently large negative is ρ ≈ (10−3eV) = 10−8ergscm−3. vac pressure leads to repulsive gravity and the acceler- The candidature of vacuum constant as dark en- ated expansion can be accommodated. In this many ergy raises two very important questions, are trying to modify the Einstein’s gravity theory it- 1. why is the vacuum energy is so smaller than what self to explain the present accelerated expansion of we would think of as its natural value ( the so called the universe. cosmological constant problem)? 2. why are the matter the matter and vacuum energy densities approximately equal today ( the so called coincidence problem.)? Conclusion Let us consider first the issue, why vacuum energy is smaller than we might expect. From the standard The problem of the dark energy is also central to to- model of particle physics, the non-vanishing conden- day’s physics. Our best attempts at a fundamental sate in the vacuum, that is the potential energy of the theory suggest the presence of a cosmological con- 4 Higgs field, is around (1011eV) , and from quantum stant that is many (perhaps as many as 120) orders 4 of magnitude greater than the upper bound set by chromodynamics, it is around (108eV) . By taking astronomical observations. For decades the prob- account of the quantum mechanical zero point fluc- lem seemed to be to find a symmetry or cancelation tuation and the "bare" classical contribution to the mechanism of some sort that would make the cos- cosmological constant, the total vacuum energy den- mological constant precisely zero. The single great- sity may come to be of the order of est failure of our most promising theories (such as theory 4 − string theories) is that they do not satisfy this re- ρ = (1027eV) = 10112ergscm 3. vac quirement. Now that a dark energy has apparently This is clearly well above the observed value, in fact been found, the problem is even harder: not just to explain why the dark energy is so tiny compared theory 120 obs ρvac ≈ 10 ρvac. with what would have been expected theoretically, This is the famous 120-orders-of-magnitude discrep- but also to explain why it happens to be of the same ancy that makes the heart of the cosmological con- order of magnitude (roughly twice) as the energy in stant problem. matter at the present moment in the history of the The second problem is the coincidence between universe. It is difficult for physicists to attack this matter and vacuum energy densities. The appropri- problem without knowing just what it is that needs ate coincidence between matter and vacuum ener- to be explained a cosmological constant or a dark en- gies in the current universe is a puzzling feature of ergy that changes with time as the universe evolves the composition of the total energy density. and for this they must rely on new observations by astronomers. Until it is solved, the problem of the dark energy will be a roadblock on our path to a com- Dynamical Dark Energy prehensive fundamental physical theory.

This model of dark energy is based on the agrement Reader that, although dark energy is uncluttered in space Dept. of Physics, CUSAT

c Department of Physics,CUSAT 10 PHYSICS/Alumni-News Vol. 2, October 2009

Student Activities

• M.K. Radhakrishnan, Nanorel, Singapore; Ad- vances in nanoelectronic devices and chal- Krishnaprasad and K.J. Saji lenges in analysis, metrology and characterization SPIE-CUSAT, IRC, Electrochemical Soci- • Dr. Aldrin Antony, Universitat de Barcelona, ety Barcelona (Spain); Roll-to-roll processes for SPIE is an international society advancing an inter- thin film silicon solar cells disciplinary approach to the science and application • Dr. S. Jayalekshmi, CUSAT; Excerpts from a of light. It supports innovative ideas and researchers "Chandrayaan Dream" in he field of optics and photonics. SPIE strives to provide resources to students that enhance their pro- • Prof. K. P. Vijayakumar, CUSAT; Third Genera- fessional development through research, education, tion Solar Cell: Physics and Materials and knowledge. SPIE CUSAT Student Chapter was • Dr.Joel Oswalt, Introduction to Raman Spec- started in 2005. troscopy, Instrumentation and its Applications Electrochemical Society (ECS) is one of the old- est association of scientists working in the area of • Dr. V. C. Kuriakose, CUSAT; Impact of Astron- solid-state and electrochemical science and technol- omy in Society ogy. ECS bridges the gaps among academia, re- • Dr. L M Kukreja, RRCAT, Indore; ZnO search, and engineering-bringing together scientists Nanorod Lasers from around the world for the exchange of technical information. ECS CUSAT Student Chapter was • Senoy Thomas, CUSAT; Magnetostriction in formed on November 2008. The formal inaguration amorphous alloys and its measurement em- of the chapter was held on 28th February 2009. ploying an optical fiber long period grating IUCAA Reference Centre (IRC) is a centre estab- • Prof. Aaron Lewis, Nanonics Imaging Ltd; lished by the Inter University Council for Astronomy Confining, Manipulating and Analyzing Light and Astrophysics (IUCAA) for research in the field in Nanodomains of astronomy and astrophysics. Centre organizes lectures and seminars in the topics related to astronomy SPIE-CUSAT chapter, in association with SPIE-IIT and astrophysics. Madras Student Chapter, conducted a national con- These student associations conduct lectures on ference on Nanophotonic Materials-NCNM 08 dur- various topics at regular intervals. Experts from var- ing October 10-12, 2008. The theme of the conference ious field of theoretical and experimental physics are was to introduce new developments in the field of invited to deliver the lectures. We conducts academic nanophotonic materials and thin film devices. The training for post graduate students of various institu- conference was mainly focused on post graduate stu- tions in Kerala and student outreach programs to at- dents and research scholars. 150 students from dif- tract talented students to the fascinating world of Sci- ferent parts of the country participated in the event ence and Technology. A ten day workshop "Physics: and experts from across the country were invited to Scope and Awareness" for school children from in- deliver lectures on topics related to nano technol- stitutions across Kerala is one of the well appreci- ogy, photonic band gap materials, nonlinear optics ated outreach programmes organised by SPIE, ECS and thinfilm devices. As a part of the conference and IRC in association with physics department. The two sessions were conducted exclusively for profes- workshop gives the young minds an exposure to sional development training. Cultural programmes various interesting aspects of physics. The ten day conducted on the eve of the conference added colors workshop provides the students a hands-on expe- to the conference. rience on various experiments in physics, telescope Some of the invited speakers are listed below: making and opportunity for students to see some • Dr.K. R. Dayas; Introduction to Nano technol- of the frontier experiments being carried out in the ogy and its applications research labs of the Department. We also conducts monthly discussions, in which students and teachers • Prof. Shanti Bhattacharya, IIT Madras; An In- of the Department of Physics actively participate. troduction to Fiber interferometry Recent speakers include: • Prof. M. S. Ramachandra Rao, IIT Madras; • Prof. G. Raja Ram, University of Hydrabad; Oxide nanostructures for electronic and optical Multilayer films for electronic applications device applications

c Department of Physics,CUSAT 11 PHYSICS/Alumni-News Vol. 2, October 2009

• Prof. P. S. Anil Kumar, IISc Bangalore; Towards with the research atmosphere at the Department of spin injection into semiconductors Physics and were also introduced to the frontier areas in physics. One complete day was spent in c- • Prof. M. Abdul Khadar, Kerala University; SiS (Center for Science in Society), an auxiliary in- Optical properties of nanoparticles/nanostruc- stitution established in the University campus to cre- tures ate scientiﬁc awareness among the public, where stu- • Dr. Reji Philip, RRI Bangalore; Photonic appli- dents got acquaintance with different scientiﬁc prin- cations of metal nanostructures ciples through SCIENCE-in-ACTION working mod- els and "See and Believe" experiments. The students • Prof. Joby Joseph, IIT Delhi; Introduction to were also given a chance to use the library facilities photonic bandgap materials during these days. The workshop was being success- • Prof. C. Vijayan, IIT Madras Nonlinear optical fully organized for the fourth year. processes in semiconductor nanomaterials • Prof. S. Achuth Shankar, Kerala University; Making powerful presentations • Prof. N. Balakrishna, CUSAT; Statistical meth- ods for the error analysis • Prem Ballabh Bisht, IIT Madras; Whispering gallery modes of nanocoated single micro- spheres

Dr. N. Chandramohanakumar (Registrar, CUSAT) inaugurating the workshop for school children

Sessions from National Conference on Nanophotonic Materials NCNM-09

Ten day workshop for School Children- "Physics: Scope and awareness" 20-30, April 2009 Dr. N. Chandramohanakumar, Registrar, CUSAT School students during the telescope making session of inaugurated the workshop on 20th April 2009. Prof. the ten day workshop Godfrey Louis, Head of the Department of Physics, presided the function, Prof V. C. Kuriakose, wel- National Science day was celebrated on February th comed the gathering and Dr. M. K. Jayaraj pro- 28 in memory of Dr. C V Raman. We celebrated the posed the vote of thanks. The workshop intended to science day by conducting various seminars and sky providing the budding youths, hands on experience watching in the evening. on various experiments in and out of their curricu- lum. Participants were also exposed to the technical Junior Research Fellow knowledge behind the making of telescope for dis- Dept. of Physics tant observations. They got a chance to familiarise [email protected]

c Department of Physics,CUSAT 12 PHYSICS/Alumni-News Vol. 2, October 2009

Dr. L.Godfrey CUSAT Pro-Vice Chancellor

work on the Red Rain Phenomenon in Kerala. Prof. Godfrey proposed a Prof. L. Godfrey, radically new hypothesis that the red colour is due to noted Astrobiologist micro particles existing in extraterrestrial biological and Solidstate Physicist cells. The British Broadcasting Corporation broad- and former head of the casted a documentary about Prof. Godfrey in UK department of physics, during 2006. took charge as the 10th Prof. Godfrey started his career as a Lecturer in Pro- Vice Chancellor of UC College, Aluva during 1981. He also served as the Cochin University a Lecturer in St. PaulŠs College, Kalamassery and of Science and Technol- School of Pure & Applied Physics, Mahatma Gandhi ogy on 27 May 2009. He University, Kottayam. He joined CUSAT as Professor is well known world- in Physics in 2006. He is also a member of Syndicate wide for his research of Mahatma Gandhi University, Kottayam.

Raveendranath - some reminiscences

B, Applied Physics Letters etc. He was also an excellent Physics Teacher and has Dr.S.Jayalekshmi put in twenty six years of continuous and committed service in the Department of Physics, Aquinas col- Like a breeze he came, lege, Kochi. Every year he used to conduct an ex- spreading the fra- hibition named ’Physics Show’ for school children, grance of knowledge with the theme “See it, Believe it and appreciate it”, among his comrades which got wide coverage in news papers. He used and went back to the to handle classes in the programme for school chil- treasure-house of in- dren “Physics: Scope and Awareness” jointly organ- ﬁnite wisdom. These ised every year by SPIE CUSAT Student Chapter and words are true about Department of Physics, CUSAT. K.Raveendranath, who To the great shock, agony and despair of his fam- was the head of the De- ily, friends, colleagues, he passed away, embracing a partment of Physics, too untimely death, on the 11th of March 2009, just Aquinas College, Kochi ten days prior to the scheduled open defence of his and also a research stu- Ph.D thesis. Taking into considerations of the exam- dent under my supervi- iners who valued his thesis and his excellent publica- sion in the Department tions, CUSAT has taken steps to award Ph.D degree of Physics, CUSAT. Within a short span of three and to this enthusiastic researcher, posthumously. a half years, that too as a part-time researcher, he His commitment to research will always be a completed the research work in one of the frontier guiding inspiration for all the blossoming junior re- research areas related to energy storage systems. Ma- searchers of our division in their often hurdled re- jor part of his research work has been published in search journeys towards ultimate success, perfection reputed international journals like Physical Review and fulﬁlment.

c Department of Physics,CUSAT 13 PHYSICS/Alumni-News Vol. 2, October 2009

ECS Interface Tech Highlights

eV in nanoparticulate form, exhibits size-dependent, quantum conﬁnement effects. Interestingly, the un- Summer issue of ECS INTERFACE highlights the doped nanoparticles exhibit an unexpectedly broad works of CUSAT researchers. ECS Tech Highlights luminescence spectrum in the visible, markedly was prepared by David Enos and Mike Kelly of San- broader than its bulk counterpart. Furthermore, dia National Laboratories, Craig Walker of Valence the photoluminescence spectra for their discussed Technology, Inc., James Dickerson of Vanderbilt Uni- 6-9 nm ZnGa2O4 nanoparticles are only nominally versity, and Donald Pile. Each article highlighted in blueshifted compared to the bulk spectrum. Addi- ECS interface is available free online. tional investigation of smaller nanoparticle sizes and P.M. Aneesh, Mini Krishna and M.K. Jayaraj, with different RE3+ dopants may shed light on av- from Department of Physics, CUSAT have devel- enues to employ undoped and doped ZnGa2O4 in a oped a hydrothermal synthesis of nanoparticulate broader range of video display and solid-state light- forms of undoped and europium-doped ZnGa2O4 ing applications. Nanoparticles. The doped version of these nanopar- 5 7 ticles exhibit the strong Dj → Fj luminescence ECS Interface Vol. 18, No. 2, Summer 2009 transitions for which Eu3+ is well known. As well, http://www.electrochem.org/dl/interface/sum/ this direct bandgap material, 4.52 eV in bulk but 4.59 sum09/sum09_p026.pdf

SIMS research award to Aneesh

Au/Pt nanoparticle condensation and their substrate effects". Aneesh obtained his M.Sc degree in Physics Mr. Aneesh Prabhakaran, an alumni of our De- from CUSAT in 2006 and currently pursuing his partment has been selected for the SIMS Research Ph.D. degree at Université catholique de Louvain in Award for Student Paper Presented at the SIMS XVII Belgium. Congratulation Mr. Aneesh. Toronto Conference for his paper "Secondary Ion http://www.simsxvii.org/studentawards.html Yield Enhancement in organic samples due to the

Recent Ph.D. award and thesis submission

• Dr. Rahana Yousaf, "Optimization of two stage process for the growth of In2S3, CuInSe2 and • Dr. Jisha C.P., "Studies on some aspects of CuIn (Se1−xS1−x) thin ﬁlms for solar cell appli- light beam propagation through certain nonlin- cation". ear media". • Dr. Asha A.S., "RF Magnetron Sputtered • Dr. Sini R., "Studies on scattering phenom- Perovskite Oxide electrodes for ferroelectric ena and quasinormal modes in black hole space RAM". times". • Dr. Ajimsha R.S., "Growth and characterization • Dr. Kuriakose P.I., "Studies on thermodynam- of ZnO based heterojunction diodes and ZnO ics and no-hair theorem in black hole space- nanostructures by pulses laser ablation". time". • Dr. Chitra R. Nayak, "Studies on Chaos and • Dr. Anila E.I., "Luminescence studies of stron- Synchronization in ac-driven Josephson Junc- tium sulphide based phosphors for display ap- tions". plications". • Dr. Radhakrishnan R., " Studies on non- • Dr. Joshy N.V., "Studies on Laser Induced and resonant multi phone processes in atomic hy- RF Sputtered Plasma using Optical Emission drogen". Spectroscopy and Langmuir Probe".

c Department of Physics,CUSAT 14 PHYSICS/Alumni-News Vol. 2, October 2009

• Dr. Saji K.J., "Amorphous Oxide Transparent Ph.D. Thesis submitted Thin Films: Growth, Characterisation and Ap- • plication to Thin Film Transistors". Anoop G. "Synthesis, Growth and Characteri- zation of Oxide Phosphors for Thin Film Elec- • Dr. Thomas P. Zacharia, "Studies of Heat Dif- troluminescent Devices". fusion in selected conducting Polymer using • Mini Krishna K. "Synthesis and Characterisa- Probe Bean deﬂection and photoacaustic tech- tion of Zinc Gallate based Phosphors for Thin nique". Film Electroluminescent Devices".

• Dr. Beena Mary John, "Fabrication and Char- • Muhammad Abdul Jamal E. "Preparation acterization of dye sensitized polymer films for and Characterization of Magnetic and Non- holographic applications". magnetic Nanosized Spinel Oxides, Nickel Nanoparticles and Nickel-Polymer Nanocom- • Dr. Sreekumar A., "Development of Solar Air posites". Heaters and Thermal Energy Storage System for drying applications in food processing In- • Veena Gopalan E. "On the Synthesis and Multi- dustries". functional Properties of some Nanocrystalline Spinel Ferrites and Magnetic Nanocompos- • Dr. Jayakrishnan R. "Defect Analysis of semi- ites". conductor thin films for photovoltaic applications using photo-luminescence and photo- • Deepa K. G., "Preparation of sub-micrometre conductivity". thick CuInSe2 films using sequential evaporation technique for device fabrication". • Dr. Sreekumar R. "Effects and Modifications in • Meril Mathew, "Engineering the properties of In/Se and In/Sb systems by Swift Heavy Ion Indium Sulfide for thin film solar cells by dop- Irradiation". ing".

• Dr. Kishore V.C., "Development of photorefrac- • Tina Sebastian, "Automation of chemical spray tive polymers: Evaluation of photoconducting pyrolysis unit and fabrication of sprayed and electro-optic properties". CuInS2/In2S3 solar cell".

c Department of Physics,CUSAT 15