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Graduate Studies in Nuclear Physics At
Graduate Studies in Atomic, Molecular, and Optical Physics at The College of William and Mary Atomic, Molecular, and Optical Group: General Information: Experimental Faculty: 4 The College of William and Mary (W&M), chartered in 1693, Theoretical Faculty: 1 is the second oldest university in the US. It boasts four US Graduate Students: 14 presidents, supreme court justices and Jon Stewart as alumni. Female Students: 5 W&M is a liberal arts university with a strong research focus. Our 7,800 students (2,000 of them graduate students) enjoy a Rankings (US News and World Report): low student-to-faculty ratio, state-of-the-art facilities, and a beautiful campus. W&M ranked 6th amongst public US universities Located in Williamsburg, Virginia, W&M is in the heart of Physics Department Statistics: colonial American history and is adjacent to Colonial Average annual number of Ph. D. recipients: 8 Williamsburg, a historic recreation of 18th century colonial Average time to Ph. D.: 5 years life. While much of the campus has been restored to its 18th- century appearance, the physics department is housed in a Departmental Website: newly refurbished and expanded building that provides http://www.wm.edu/physics outstanding teaching and research space. http://www.wm.edu/as/physics/research/index.php The William and Mary physics department benefits Graduate Admissions: enormously from close ties with both Thomas Jefferson http://www.wm.edu/as/physics/grad/index.php National Accelerator Facility (JLab) and NASA Langley Application deadline: Feb 1st Research Center in nearby Newport News (thirty minutes from the W&M campus). -
Quantitative Force Measurements with Optical Tweezers: the JPK Nanotracker™
Quantitative force measurements with optical tweezers: The JPK NanoTracker™ Introduction to optical tweezers manipulate biomolecules and cells, but also to directly and accurately measure the minute forces (on the order of Optical tweezers methodology has developed from proof-of- fractions of picoNewtons) involved. Most often, the principle experiments to an established quantitative biomolecules of interest are not trapped themselves technique in fields ranging from (bio)physics through cell directly, but manipulated through functionalized biology. As the name suggests, optical tweezers are a microspheres. means to manipulate objects with light. With this technique, The correct physical description of optical trapping depends microscopically small objects can be held and manipulated. on the size of the trapped object. One speaks of the ‘ray- At the same time, the forces exerted on the trapped objects optics’ regime when the object’s dimension d is much larger can be accurately measured. The basic physical principle than the wavelength of the trapping light: d>>λ. In this case, underlying optical tweezers is the radiation pressure diffraction effects can be neglected and the trapping forces exerted by light when colliding with matter. For macroscopic of the light can be understood in terms of ray optics. The objects, the radiation pressure exerted by typical light regime where d<<λ is called the Rayleigh regime. In this sources is orders of magnitude too small to have any case, the trapped particles can be treated as point dipoles, measurable effect: we do not feel the light power of the sun as the electromagnetic field is constant on the scale of the pushing us away. -
Direct Frequency Comb Laser Cooling and Trapping
Selected for a Viewpoint in Physics PHYSICAL REVIEW X 6, 041004 (2016) Direct Frequency Comb Laser Cooling and Trapping A. M. Jayich,* X. Long, and W. C. Campbell Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, California 90095, USA and California Institute for Quantum Emulation, Santa Barbara, California 93106, USA (Received 11 May 2016; published 10 October 2016) Ultracold atoms, produced by laser cooling and trapping, have led to recent advances in quantum information, quantum chemistry, and quantum sensors. A lack of ultraviolet narrow-band lasers precludes laser cooling of prevalent atoms such as hydrogen, carbon, oxygen, and nitrogen. Broadband pulsed lasers can produce high power in the ultraviolet, and we demonstrate that the entire spectrum of an optical frequency comb can cool atoms when used to drive a narrow two-photon transition. This multiphoton optical force is also used to make a magneto-optical trap. These techniques may provide a route to ultracold samples of nature’s most abundant building blocks for studies of pure-state chemistry and precision measurement. DOI: 10.1103/PhysRevX.6.041004 Subject Areas: Atomic and Molecular Physics I. INTRODUCTION ultraviolet means that laser cooling and trapping is not currently available for the most prevalent atoms in organic High-precision physical measurements are often under- chemistry: hydrogen, carbon, oxygen, and nitrogen. taken close to absolute zero temperature to minimize Because of their simplicity and abundance, these species, thermal fluctuations. For example, the measurable proper- with the addition of antihydrogen, likewise play prominent ties of a room temperature chemical reaction (rate, roles in other scientific fields such as astrophysics [11] and product branching, etc.) include a thermally induced precision measurement [12], where the production of average over a large number of reactant and product cold samples could help answer fundamental outstanding quantum states, which masks the unique details of questions [13–15]. -
A Quantum Origin of Life?
June 26, 2008 11:1 World Scientific Book - 9in x 6in quantum Chapter 1 A Quantum Origin of Life? Paul C. W. Davies The origin of life is one of the great unsolved problems of science. In the nineteenth century, many scientists believed that life was some sort of magic matter. The continued use of the term “organic chemistry” is a hangover from that era. The assumption that there is a chemical recipe for life led to the hope that, if only we knew the details, we could mix up the right stuff in a test tube and make life in the lab. Most research on biogenesis has followed that tradition, by assuming chemistry was a bridge—albeit a long one—from matter to life. Elucidat- ing the chemical pathway has been a tantalizing goal, spurred on by the famous Miller-Urey experiment of 1952, in which amino acids were made by sparking electricity through a mixture of water and common gases [Miller (1953)]. But this concept turned out to be something of a blind alley, and further progress with pre-biotic chemical synthesis has been frustratingly slow. In 1944, Erwin Schr¨odinger published his famous lectures under the ti- tle What is Life? [Schr¨odinger (1944)] and ushered in the age of molecular biology. Sch¨odinger argued that the stable transmission of genetic infor- mation from generation to generation in discrete bits implied a quantum mechanical process, although he was unaware of the role of or the specifics of genetic encoding. The other founders of quantum mechanics, including Niels Bohr, Werner Heisenberg and Eugene Wigner shared Schr¨odinger’s belief that quantum physics was the key to understanding the phenomenon Received May 9, 2007 3 QUANTUM ASPECTS OF LIFE © Imperial College Press http://www.worldscibooks.com/physics/p581.html June 26, 2008 11:1 World Scientific Book - 9in x 6in quantum 4 Quantum Aspects of Life of life. -
Depth-Resolved Measurement of Optical Radiation-Pressure Forces with Optical Coherence Tomography
Vol. 26, No. 3 | 5 Feb 2018 | OPTICS EXPRESS 2410 Depth-resolved measurement of optical radiation-pressure forces with optical coherence tomography NICHALUK LEARTPRAPUN, RISHYASHRING R. IYER, AND STEVEN G. ADIE* Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853, USA *[email protected] Abstract: A weakly focused laser beam can exert sufficient radiation pressure to manipulate microscopic particles over a large depth range. However, depth-resolved continuous measurement of radiation-pressure force profiles over an extended range about the focal plane has not been demonstrated despite decades of research on optical manipulation. Here, we present a method for continuous measurement of axial radiation-pressure forces from a weakly focused beam on polystyrene micro-beads suspended in viscous fluids over a depth range of 400 μm, based on real-time monitoring of particle dynamics using optical coherence tomography (OCT). Measurements of radiation-pressure forces as a function of beam power, wavelength, bead size, and refractive index are consistent with theoretical trends. However, our continuous measurements also reveal localized depth-dependent features in the radiation- pressure force profiles that deviate from theoretical predictions based on an aberration-free Gaussian beam. The combination of long-range radiation pressure and OCT offers a new mode of quantitative optical manipulation and detection with extended spatial coverage. This may find applications in the characterization of optical tractor beams, or volumetric optical manipulation and interrogation of beads in viscoelastic media. © 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement OCIS codes: (110.4500) Optical coherence tomography; (350.4855) Optical tweezers or optical manipulation. -
(Ruby 1960) • Uses a Solid Matrix Or Crystal Carrier • Eg Glass Or Sapphire
Solid State Lasers • Was first type of laser (Ruby 1960) • Uses a solid matrix or crystal carrier • eg Glass or Sapphire • Doped with ~1%-0.001% transition metal or rear earth ions • eg Chromium (Cr) or Neodynmium (Nd) • Mirrors at cavity ends (either on the rod or separate) • Typically pumped with light • Most common a Flash lamp • Newer ones pumped by laser diodes (more efficient) • Light adsorbed by doped ion, emitted as laser light • Mostly operates in pulsed mode (newer CW) Flash Lamp Pumping • Use low pressure flash tubes (like electronic flash) • Xenon or Krypton gas at a few torr (mm of mercury pressure) • Electrodes at each end of tube • Charge a capacitor bank: 50 - 2000 µF, 1-4 kV • High Voltage pulse applied to tube • Ionizes part of gas • Makes tube conductive • Capacitor discharges through tube • Few millisec. pulse • Inductor slows down discharge Light Source Geometry • Earlier spiral lamp: inefficient but easy • Now use reflectors to even out light distribution • For CW operation use steady light sources Tungsten Halogen or Mercury Vapour • Use air or water cooling on flash lamps Q Switch Pulsing • Most solid states use Q switching to increase pulse power • Block a cavity with controllable absorber or switch • Acts like an optical switch • During initial pumping flash pulse switch off • Recall the Quality Factor of resonance circuits (eg RLC) 2π energy stored Q = energy lost per light pass • During initial pulse Q low • Allows population inversion to increase without lasing • No stimulated emission • Then turn switch on -
Three-Dimensional Laser Cooling at the Doppler Limit R
Three-dimensional laser cooling at the Doppler limit R. Chang, A. L. Hoendervanger, Q. Bouton, Y. Fang, T. Klafka, K. Audo, Alain Aspect, C. I. Westbrook, D. Clément To cite this version: R. Chang, A. L. Hoendervanger, Q. Bouton, Y. Fang, T. Klafka, et al.. Three-dimensional laser cooling at the Doppler limit. Physical Review A, American Physical Society, 2014, 90 (6), pp.063407. 10.1103/PhysRevA.90.063407. hal-01068704 HAL Id: hal-01068704 https://hal.archives-ouvertes.fr/hal-01068704 Submitted on 22 Feb 2015 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Copyright Three-Dimensional Laser Cooling at the Doppler limit R. Chang,1 A. L. Hoendervanger,1 Q. Bouton,1 Y. Fang,1, 2 T. Klafka,1 K. Audo,1 A. Aspect,1 C. I. Westbrook,1 and D. Cl´ement1 1Laboratoire Charles Fabry, Institut d'Optique, CNRS, Univ. Paris Sud, 2 Avenue Augustin Fresnel 91127 PALAISEAU cedex, France 2Quantum Institute for Light and Atoms, Department of Physics, State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, 200241, China Many predictions of Doppler cooling theory of two-level atoms have never been verified in a three- dimensional geometry, including the celebrated minimum achievable temperature ~Γ=2kB , where Γ is the transition linewidth. -
Optical Micromachines for Biological Studies
micromachines Review Optical Micromachines for Biological Studies Philippa-Kate Andrew 1 , Martin A. K. Williams 2,3 and Ebubekir Avci 1,3,* 1 Department of Mechanical and Electrical Engineering, Massey University, Palmerston North 4410, New Zealand; [email protected] 2 School of Fundamental Sciences, Massey University, Palmerston North 4410, New Zealand; [email protected] 3 MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington 6140, New Zealand * Correspondence: [email protected] Received: 21 January 2020; Accepted: 9 February 2020; Published: 13 February 2020 Abstract: Optical tweezers have been used for biological studies since shortly after their inception. However, over the years research has suggested that the intense laser light used to create optical traps may damage the specimens being studied. This review aims to provide a brief overview of optical tweezers and the possible mechanisms for damage, and more importantly examines the role of optical micromachines as tools for biological studies. This review covers the achievements to date in the field of optical micromachines: improvements in the ability to produce micromachines, including multi-body microrobots; and design considerations for both optical microrobots and the optical trapping set-up used for controlling them are all discussed. The review focuses especially on the role of micromachines in biological research, and explores some of the potential that the technology has in this area. Keywords: optical tweezers; multi-component micromanipulators; radiation damage; life sciences; optical microrobots 1. Introduction Improvements in tools for the visualisation of objects at the micro- and nano- scale have given researchers the ability to investigate materials and processes previously out of reach. -
Pulsed Optical Tweezers for Levitation and Manipulation of Stuck Biological
2005 Conference on Lasers & Electro-Optics (CLEO) CFN3 Pulsed optical tweezers for levitation and manipulation of stuck biological particles Amol Ashok Ambardekar and Yong-qing Li Department ofPhysics, East Carolina University, Greenville, North Carolina 27858 acube3(1!yahoo. covm,livrnail.ecu. ec/ Abstract: We report on optical levitation and manipulation of microscopic particles that are stuck on a glass surface with a pulsed optical tweezers. Both the stuck dielectric beads and biological cells are demonstrated to be levitated. ©2005 Optical Society of America OCIS codes: (170.4520) Optical confinement and manipulation; (140.7010) Trapping Optical tweezers has become a powerful tool for capturing and manipulation of micron-sized particles, typically by using continuous-wave (cw) lasers [1, 2]. It has been routinely applied to manipulate living cells, bacteria, viruses, chromosomes and other organelles [3, 4], To reduce the photodamage to the trapped particles, the average power of the trapping lasers is usually limited to below hundreds of mW and near-infrared (NIR) or infrared lasers were used for trapping [3, 6]. The trapping force generated by the cw optical tweezers is typically in the order of 10-12 N [4, 5]. This weak force is efficient to confine micro-particles suspended in liquids, but not sufficient to levitate the particles that are stuck on the glass surface, where it has to overcome the binding force. Therefore, the stuck particles cannot be manipulated with the optical tweezers that only employs cw lasers. In this paper, we describe a pulsed optical tweezers that employs a pulsed laser for levitation of the stuck particles and a low-power cw laser for successive trapping and manipulation. -
Laser Cooling of Two Trapped Ions: Sideband Cooling Beyond the Lamb-Dicke Limit
PHYSICAL REVIEW A VOLUME 59, NUMBER 5 MAY 1999 Laser cooling of two trapped ions: Sideband cooling beyond the Lamb-Dicke limit G. Morigi,1 J. Eschner,2 J. I. Cirac,1 and P. Zoller1 1Institut fu¨r Theoretische Physik, Universita¨t Innsbruck, A-6020 Innsbruck, Austria 2Institut fu¨r Experimentalphysik, Universita¨t Innsbruck, A-6020 Innsbruck, Austria ~Received 8 December 1998! We study laser cooling of two ions that are trapped in a harmonic potential and interact by Coulomb repulsion. Sideband cooling in the Lamb-Dicke regime is shown to work analogously to sideband cooling of a single ion. Outside the Lamb-Dicke regime, the incommensurable frequencies of the two vibrational modes result in a quasicontinuous energy spectrum that significantly alters the cooling dynamics. The cooling time decreases nonlinearly with the linewidth of the cooling transition, and the effect of dark states which may slow down the cooling is considerably reduced. We show that cooling to the ground state is also possible outside the Lamb-Dicke regime. We develop the model and use quantum Monte Carlo calculations for specific examples. We show that a rate equation treatment is a good approximation in all cases. @S1050-2947~99!11605-6# PACS number~s!: 32.80.Pj, 42.50.Vk, 03.67.Lx I. INTRODUCTION sideband cooling of two ions to the ground state has been achieved in a Paul trap that operates in the Lamb-Dicke limit The emergence of schemes that utilize trapped ions or @11#. However in this experiment the Lamb-Dicke regime atoms for quantum information, and the interest in quantum required such a high trap frequency that the distance between statistics of ultracold atoms, have provided renewed interest the ions does not allow their individual addressing with a and applications for laser cooling techniques @1#. -
Laser Cooling Yb + Ions with an Optical Frequency Comb
UNIVERSITY OF CALIFORNIA Los Angeles Laser cooling Yb+ ions with optical frequency comb A dissertation submitted in partial satisfaction of the requirements for the degree Doctor of Philosophy in Physics by Michael Ip 2018 c Copyright by Michael Ip 2018 ABSTRACT OF THE DISSERTATION Laser cooling Yb+ ions with optical frequency comb by Michael Ip Doctor of Philosophy in Physics University of California, Los Angeles, 2018 Professor Wesley C. Campbell, Chair Trapped atomic ions are a multifaceted platform that can serve as a quan- tum information processor, precision measurement tool and sensor. How- ever, in order to perform these experiments, the trapped ions need to be cooled substantially below room temperature. Doppler cooling has been a tremendous work horse in the ion trapping community. Hydrogen-like ions are good candidates because they have typically have a simple closed cycling transition that requires only a few lasers to Doppler cool. The 2S to 2P transition for these ions however typically lies in the UV to deep UV regime which makes buying a standard CW laser difficult as optical power here is hard to come by. Rather using a CW laser, which requires frequency stabilization and produces low optical power, this thesis explores how a mode-locked laser in the comb regime Doppler cools Yb ions. This thesis explores how a mode-locked laser is able to laser cool trapped ions and the consequences of using a broad spectrum light source. I will first give an overview of the architecture of our oblate Paul trap. Then I will discuss how a 10 picosecond optical pulse with a repetition rate of 80 MHz 2 2 interacts with a 20 MHz linewidth S1=2 to P1=2 transition. -
Gaming Guns Will Travel 64
— 1 — “Right on Target: how to start, have fun, & make money with a live gaming business” Published by Lander Publishing 1/6 Graham St Underwood QLD 4119, Australia Www.BattlefieldSports.com First published April 2007 Second Edition August 2007 Third Edition, September 2010 Copyright © 2007, 2010, 2013 Nicole Lander & Peter Lander All rights reserved. No part of this book may be reproduced without the permission of the copy‐ right owners. Disclaimer. The material in this publication is of a general nature, and neither purports nor intends to be advice. Readers should not act on the basis of any matter in this publication without taking professional advice from a licensed Account‐ ant or Financial Planner, and or legal attorney, with due regard to their own particular circumstances. The authors and publisher expressly disclaim all and any liability to any person, whether a purchaser of this publication or not, in respect of anything and of the consequences of anything done or omitted to be done by any such person in reliance, whether whole or in part, upon the whole or any part of the contents of this publication. Battlefield Live® and Battlefield Sports® are trademarks or pending trade‐ marks registered by Scapequest Pty Ltd and is used with its permission. Designed and typeset by Nicole Lander ISBN: 978‐0‐9803671‐1‐9 — 2 — Acknowledgements Photography: Nicole ‘Zev‐va’ Lander, Canditta ‘Angel’ Anderson, Suzette ‘Agent Starling’ Castle, Lt Col Trevor Browne, Commandant, Barbados Cadet Corps, Donna ‘Shutter’ Pre‐ ston, Ivy ‘Horse’ Grcic, Nick ‘Guerrero’ Evans, Jerry ‘Firepower’ Munsie, Lee ‘Arbalest’ Bargwanna, Leigh Lalonde, Rebecca Stallworthy, Robyn Daniels, Cameron ‘Brat’ Boyle, Paul ‘Dogsbody’ Diamond, and Robert ‘Bear’ Lander.