DOCSLIB.ORG

Experiment and Theory: No Spasing from Core-Shell Spasers

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Experiment and Theory: No Spasing from Core-Shell Spasers Experiment and Theory: No Spasing from Core-Shell Spasers Günter Kewes,1 Kathrin Höfner,2 Andreas Ott,3 Rogelio Rodriguez-Oliveros,2 Alexander Kuhlicke,1 Yan Lu,3 Matthias Ballauff,3 Kurt Busch,2, 4 and Oliver Benson1 1AG Nanooptik, Institut für Physik, Humboldt-Universität zu Berlin, Newtonstrasse 15, 12489 Berlin, Germany 2AG Theoretische Optik & Photonik, Institut für Physik, Humboldt-Universität zu Berlin, Newtonstrasse 15, 12489 Berlin, Germany 3Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB), Hahn-Meitner-Platz 1, 14109 Berlin, Germany 4Max-Born Institut, Max-Born-Strasse 2a, 12489 Berlin, Germany In 2009 the smallest laser-device consisting of a single 14 nm gold sphere and a dye-doped coating was “demonstrated” [1] based on the proposal of the “spaser” from 2003 [2]. Here, we critically evaluate so far reported results on both an experimental and on a theoretical basis. Experiments: Core-shell spasers were chemically synthesized or metal nanoparticles were coated with dye-doped polymer films. Various excitation schemes were tested, yielding laser or laser-like signatures. All of them, however, were later identified to stem from sources other than spasing. Theory: A fully analytic model for spherical core-shell spasers was developed: Within this model, we drop the widely used quasi-static approximation of the electromagnetic field in favor of fully electromagnetic Mie theory. This allows for precise incorporation of realistic gain relaxation rates (quenching and cavity-to-gain coupling) that so far have only been estimated (and massively underestimated) in spaser theory. The model unravels multiple severe limitations (that exist all over the VIS) concerning the threshold-pump, the extreme gain-medium requirements and the unavoidable heat production (independent of excitation scheme). These limits basically result from the poor quality-factors and the surprisingly poor β-factors (ratio of gain-to-cavity coupling to the overall decay rate) in such laser architectures. Beyond pessimism, our theoretical model gives advice on how to construct ultra-small lasers with reasonable performance. Especially nano-cavities made from high index dielectrics with low losses – hosting electric and magnetic Mie resonances - , e.g., Si or GaP may be the resonator materials in future efficient nano- or micro-laser devices. Thus, our model marks to ultimate limit in laser miniaturization that may impact current aims to realize more and more communication in networks or even on-chip with small lasers of high bandwidth like VCSELs. [1] M. A. Noginov, G. Zhu, A. M. Belgrave, R. Bakker, V. M. Shalaev, E. E. Narimanov, S. Stout, E. Herz, T. Suteewong, and U. Wiesner, “Demonstration of a spaser-based nanolaser,” Nature, vol. 460, no. 7259, pp. 1110–1112, 2009. [2] D. J. Bergman and M. I. Stockman, “Surface plasmon amplification by stimulated emission of radiation: quantum generation of coherent surface plasmons in nanosystems,” Phys. Rev. Lett., no. January, pp. 1–4, 2003. Contact info: Günter Kewes Tel.: 030 2093 4901 Humboldt Universität zu Berlin Institut für Physik, AG Nanooptik Newtonstraße 15 12489 Berlin Education/ current position: Günter Kewes studied physics at the RWTH Aachen, however changed to the HU Berlin to do his Diploma in the group of Prof. Oliver Benson, where he also works on his PhD project in the SFB 951 (B2). He is currently just about to finish his PhD thesis. Research interests: • Plasmonic and dielectric nano-antennas (e.g.., see „A fully nanoscopic dielectric laser“, arXiv:1412:4549 (2014)) • Coupling of emitters with nano-localized cavity-modes or guided modes (e.g., see ”Single Defect Centers in Diamond Nanocrystals as Quantum Probes for Plasmonic Nanostructures”, Optics Express, 19, Issue 8, (2011)) • Plasmonic responses from 2D materials (e.g., see „Evidence for graphene plasmons in the visible spectral range probed by molecules“, arXiv:1404.6518 (2014)) • Numerical Maxwell-equation solving with FEM (e.g., see “Design and numerical optimization of an easy-to-fabricate photon-to-plasmon coupler for quantum plasmonics”, APL, 102:051104 (2013).) .
Load more

Recommended publications
  • SPASER As a Complex System: Femtosecond Dynamics Traced by Ab-Initio Simulations
    SPASER as a complex system: femtosecond dynamics traced by ab-initio simulations Item Type Conference Paper Authors Gongora, J. S. Totero; Miroshnichenko, Andrey E.; Kivshar, Yuri S.; Fratalocchi, Andrea Citation Juan Sebastian Totero Gongora ; Andrey E. Miroshnichenko ; Yuri S. Kivshar and Andrea Fratalocchi " SPASER as a complex system: femtosecond dynamics traced by ab-initio simulations ", Proc. SPIE 9746, Ultrafast Phenomena and Nanophotonics XX, 974618 (March 14, 2016); doi:10.1117/12.2212967; http:// dx.doi.org/10.1117/12.2212967 Eprint version Publisher's Version/PDF DOI 10.1117/12.2212967 Publisher SPIE-Intl Soc Optical Eng Journal Ultrafast Phenomena and Nanophotonics XX Rights Copyright 2016 Society of Photo Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited. Download date 27/09/2021 00:14:10 Link to Item http://hdl.handle.net/10754/619757 SPASER as a complex system: femtosecond dynamics traced by ab-initio simulations Juan Sebastian Totero Gongoraa, Andrey E. Miroshnichenkob, Yuri S. Kivsharb, and Andrea Fratalocchia aPRIMALIGHT, King Abdullah University of Science and Technology (KAUST),Thuwal 23955-6900, Saudi Arabia bNonlinear Physics Centre, Australian National University, Canberra ACT 2601, Australia. ABSTRACT Integrating coherent light sources at the nanoscale with spasers is one of the most promising applications of plasmonics. A spaser is a nano-plasmonic counterpart of a laser, with photons replaced by surface plasmon polaritons and the resonant cavity replaced by a nanoparticle supporting localized plasmonic modes.
    [Show full text]
  • Synthesis and SERS Application of Sio2@Au Nanoparticles
    Synthesis and SERS application of SiO2@Au nanoparticles A. Saini, T. Maurer*, I. Izquierdo Lorenzo, A. Ribeiro Santos, J. Béal, J. Goffard, D. Gérard, A. Vial and J. Plain Laboratoire de Nanotechnologie et d’Instrumentation Optique, ICD CNRS UMR n°6281, Université de Technologie de Troyes, CS 42060, 10004 Troyes, France In this letter, we report a chemical route for synthesizing SiO2@Au core-shell nanoparticles. The process includes four steps: i) preparation of the silica cores, ii) grafting gold nanoparticles over SiO2 cores, iii) priming of the silica-coated gold nanoparticles with 2 and 10 nm gold colloids and finally iv) formation of complete shell. The optical extinction spectra were experimentally measured and compared to numerical calculations in order to confirm the dimensions deduced from SEM images. Finally, the potential of such core- shell nanoparticles for biosensing was probed by means of Surface Enhanced Raman Scattering measurements and revealed higher sensitivities with much lower gold quantity of such core-shell nanoparticles compared to Au nanoparticles exhibiting similar diameters. SiO2 core-Au shell nanoparticles have attracted much attention for the past ten years due to potential applications in various fields such as cancer imaging and treatment(Loo et al., 2004), Surface-Enhanced Raman Spectroscopy (SERS) detection of molecules(Wang et al., 2006, Maurer et al., 2013), catalytic degradation of environmental pollutants(Ma et al., 2009) or even fabrication of SPASER (Surface Plasmon Amplification by Stimulated Emission of radiation) devices when the silica is dye-doped(Stockman, 2008). However, the growth of a complete gold shell around silica nanoparticles is very hard to achieve.
    [Show full text]
  • Plasmon Lasers
    Plasmon Lasers Wenqi Zhu1,2, Shawn Divitt1,2, Matthew S. Davis1, 2, 3, Cheng Zhang1,2, Ting Xu4,5, Henri J. Lezec1 and Amit Agrawal1, 2* 1Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899 USA 2Maryland NanoCenter, University of Maryland, College Park, MD 20742 USA 3Department of Electrical Engineering and Computer Science, Syracuse University, Syracuse, NY 13244 USA 4National Laboratory of Solid-State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing, China 5Collaborative Innovation Center of Advanced Microstructures, Nanjing, China Corresponding*: [email protected] Recent advancements in the ability to design, fabricate and characterize optical and optoelectronic devices at the nanometer scale have led to tremendous developments in the miniaturization of optical systems and circuits. Development of wavelength-scale optical elements that are able to efficiently generate, manipulate and detect light, along with their subsequent integration on functional devices and systems, have been one of the main focuses of ongoing research in nanophotonics. To achieve coherent light generation at the nanoscale, much of the research over the last few decades has focused on achieving lasing using high- index dielectric resonators in the form of photonic crystals or whispering gallery mode resonators. More recently, nano-lasers based on metallic resonators that sustain surface plasmons – collective electron oscillations at the interface between a metal and a dielectric – have emerged as a promising candidate. This article discusses the fundamentals of surface plasmons and the various embodiments of plasmonic resonators that serve as the building block for plasmon lasers.
    [Show full text]
  • SPASERS: Nano-Lasers Going Beyond the Diffraction Limit
    SPASERS: Nano-Lasers Going Beyond the Diffraction Limit Belinda Pacheco Literature Seminar November 9, 2017 A SPASER (Surface Plasmon Amplification by Stimulated Emission of Radiation) is a nanoscale version of a laser that has been recently theorized and experimentally demonstrated.1,2 SPASERs can be considered counterparts to the laser since they are intense, coherent light sources and require a resonator cavity-like structure with gain media. However, SPASERs dramatically differ from lasers in two ways: 1) their resonator and gain medium structures are on the nanoscale, and 2) the stimulated emission originates from overpopulation of surface plasmons in excited states, and not population inversion in the gain medium. Consequently, SPASERs can uniquely overcome the diffraction limit which is detrimental to the spatial footprint and physical size of the 3 typical laser. Based on these characteristics SPASERs (a) show tremendous prospects in fields where lasers have become limiting factors such as in ultramicroscopy, spectroscopy, ultrasensitive detection, imaging, biomedical applications, optical communications, and lab-on-a-chip devices.1,4–6 However, SPASERs have not been successfully implemented into these technologies because of their inherent lack of beam directionality and significant radiative losses.4 Despite their shortcomings, recent efforts in materials chemistry, materials science, and nano-optics (b) have provided routes for overcoming these limitations. To understand the lasing action of a SPASER, it is essential to understand the fundamentals of surface plasmons. In essence, surface plasmons (SPs) are oscillations of conduction band electrons at the interface between materials of different dielectric permittivity.7 SPs are naturally coupled to electromagnetic waves allowing them to be considered a type of boson (a polariton), thereby acting similarly to photons (i.e.
    [Show full text]
  • Open Resonator Electric Spaser Bobo Liu,† Weiren Zhu,‡ Sarath D
    Article www.acsnano.org Open Resonator Electric Spaser Bobo Liu,† Weiren Zhu,‡ Sarath D. Gunapala,§ Mark I. Stockman,# and Malin Premaratne*,† † Advanced Computing and Simulation Laboratory (AχL), Department of Electrical and Computer Systems Engineering, Monash University, Clayton, Victoria 3800, Australia ‡ Department of Electronic Engineering, Shanghai Jiao Tong University, Shanghai 200240, People’s Republic of China § Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, United States # Center for Nano-Optics and Department of Physics and Astronomy, Georgia State University, Atlanta, Georgia 30303, United States *S Supporting Information ABSTRACT: The inception of the plasmonic laser or spaser (surface plasmon amplification by stimulated emission of radiation) concept in 2003 provides a solution for overcoming the diffraction limit of electromagnetic waves in miniaturization of traditional lasers into the nanoscale. From then on, many spaser designs have been proposed. However, all existing designs use closed resonators. In this work, we use cavity quantum electrodynamics analysis to theoretically demonstrate that it is possible to design an electric spaser with an open resonator or a closed resonator with much weak feedback in the extreme quantum limit in an all-carbon platform. A carbon nanotube quantum dot plays the role of a gain element, and Coulomb blockade is observed. Graphene nanoribbons are used as the resonator, and surface plasmon polariton field distribution with quantum electrodynamics features can be observed. From an engineering perspective, our work makes preparations for integrating spasers into nanocircuits and/or photodynamic therapy applications. KEYWORDS: spaser, graphene, Coulomb blockade, carbon nanotube, plasmon n nanoplasmonics, the spaser (surface plasmon amplifica- in which, the gain medium employed a semiconductor cascade tion by stimulated emission of radiation) is a promising quantum well structure.
    [Show full text]
  • Magneto-Optical Spaser
    2002 OPTICS LETTERS / Vol. 38, No. 12 / June 15, 2013 Magneto-optical spaser D. G. Baranov,1,2 A. P. Vinogradov,1,2 A. A. Lisyansky,3,* Yakov M. Strelniker,4 and David J. Bergman5 1Moscow Institute of Physics and Technology, 9 Institutskiy per., Dolgoprudniy, Moscow 141701, Russia 2Institute for Theoretical and Applied Electromagnetics, 13 Izhorskaya, Moscow 125412, Russia 3Department of Physics, Queens College of the City University of New York, Queens, New York 11367, USA 4Department of Physics, Bar-Ilan University, Ramat-Gan IL-52900, Israel 5Raymond and Beverly Sackler School of Physics and Astronomy, Faculty of Exact Sciences, Tel Aviv University, Tel Aviv IL-69978, Israel *Corresponding author: [email protected] Received December 26, 2012; revised April 28, 2013; accepted May 8, 2013; posted May 8, 2013 (Doc. ID 182465); published June 3, 2013 We present an electrodynamical model of a quantum plasmonic device—the magneto-optical (MO) spaser. It is shown that a spherical gain nanoparticle coated with a metallic MO shell can operate as a spaser amplifying circularly polarized surface plasmons. The MO spaser may be used in design of an optical isolator in plasmonic transmission lines as well as in spaser spectrometry of chiral molecules. © 2013 Optical Society of America OCIS codes: (240.6680) Surface plasmons; (140.3410) Laser resonators; (310.6628) Subwavelength structures, nanostructures; (350.4238) Nanophotonics and photonic crystals; (230.3810) Magneto-optic systems. http://dx.doi.org/10.1364/OL.38.002002 Recently, nanosources of coherent light have attracted Maxwell’s equation, while the dynamics of the polariza- significant attention [1]. After [2], different plasmonic- tion and the population inversion of active atoms n are based light sources have been studied theoretically governed by the equations following from the density [3–5] and realized experimentally [6–8].
    [Show full text]
  • A Novel Metal Nanoparticles-Graphene Nanodisks-Quantum Dots Hybrid-System-Based Spaser
    nanomaterials Article A Novel Metal Nanoparticles-Graphene Nanodisks-Quantum Dots Hybrid-System-Based Spaser Mariam M. Tohari 1,* , Andreas Lyras 2 and Mohamad S. AlSalhi 2,3 1 Department of Physics, College of Science, King Khalid University, P.O. Box 9004, Abha 62529, Saudi Arabia 2 Department of Physics and Astronomy, College of Science, King Saud University, P. O. Box 11451, Riyadh 11451, Saudi Arabia; [email protected] (A.L.); [email protected] (M.S.A.) 3 Research Chair on Laser Diagnosis of Cancers, College of Science, King Saud University, Riyadh 11451, Saudi Arabia * Correspondence: [email protected] Received: 01 January 2020; Accepted: 22 February 2020; Published: 27 February 2020 Abstract: Active nanoplasmonics have recently led to the emergence of many promising applications. One of them is the spaser (surface plasmons amplification by stimulated emission of radiation) that has been shown to generate coherent and intense fields of selected surface plasmon modes that are strongly localized in the nanoscale. We propose a novel nanospaser composed of a metal nanoparticles-graphene nanodisks hybrid plasmonic system as its resonator and a quantum dots cascade stack as its gain medium. We derive the plasmonic fields induced by pulsed excitation through the use of the effective medium theory. Based on the density matrix approach and by solving the Lindblad quantum master equation, we analyze the ultrafast dynamics of the spaser associated with coherent amplified plasmonic fields. The intensity of the plasmonic field is significantly affected by the width of the metallic contact and the time duration of the laser pulse used to launch the surface plasmons.
    [Show full text]
  • Arxiv:1909.11113V2 [Cond-Mat.Mes-Hall] 4 Oct 2019 the Spaser Geometry of Ref
    Topological Spaser Jhih-Sheng Wu,∗ Vadym Apalkov,y and Mark I. Stockmanz Center for Nano-Optics (CeNO) and Department of Physics and Astronomy, Georgia State University, Atlanta, Georgia 30303 (Dated: October 8, 2019) We theoretically introduce a topological spaser, which consists of a hexagonal array of plasmonic metal nanoshells containing an achiral gain medium in their cores. Such a spaser can generate two mutually time-reversed chiral surface plasmon modes in the K- and K0-valleys, which carry the opposite topological charges, ±1, and are described by a two-dimensional E0 representation of the D3h point symmetry group. Due to the mode competition, this spaser exhibits a bistability: only one of these two modes generates, which is a spontaneous symmetry breaking. Such a spaser can be used for an ultrafast all-optical memory and information processing The concept of the surface plasmon amplification by of two different sublattices is provided by the transition stimulated emission of radiation (spaser, also called plas- metal dichalcogenide (TMDC) crystals [28{30]. monic nanolaser) [1{3] has recently been experiencing The spasing eigenmodes are surface plasmons (SPs) rapid development. Many different types of spasers that should be classified corresponding to irreducible rep- have been proposed [4{7] and demonstrated [8{18]. The resentations of the symmetry point group of the lattice spasers were also applied to various problems includ- unit cell, which is D3h [31]. This group has six represen- ing explosives detection [19], monitoring of the nano- tations, of which E0 is a two-dimensional (doublet) rep- environment [20, 21], cancer therapeutics and diagnostics resentation with the desired properties { see Appendix.
    [Show full text]
  • Hybrid Plasmonic-Photonic Nanostructures for Enhanced
    ADVERTIMENT. Lʼaccés als continguts dʼaquesta tesi queda condicionat a lʼacceptació de les condicions dʼús establertes per la següent llicència Creative Commons: http://cat.creativecommons.org/?page_id=184 ADVERTENCIA. El acceso a los contenidos de esta tesis queda condicionado a la aceptación de las condiciones de uso establecidas por la siguiente licencia Creative Commons: http://es.creativecommons.org/blog/licencias/ WARNING. The access to the contents of this doctoral thesis it is limited to the acceptance of the use conditions set by the following Creative Commons license: https://creativecommons.org/licenses/?lang=en i Aquesta tesi doctoral està subjecta a la llicència Reconeixement – NoCommercial – CompartirIgual 4.0 Espanya Creative Commons (cc by-nc-sa) Esta tesis doctoral está sujeta a la licencia Reconocimiento – NoCommercial – ComartirIgual 4.0 España de Creative Commons (cc by-nc-sa) This doctoral thesis is licenced under the Creative Commons Attribution – NonCommercial – ShareAlike 4.0 Spain License (cc by-nc-sa) ii iii iv ACKNOWLEDGEMENT Questa tesi non sarebbe stata possibile senza tutte quelle persone che durante questi quattro anni mi hanno supportato e sopportato. È il frutto di complicitá, amicizia, professionalitá, impegno e un po’ di ansia. Hacía cuatro años no pensaba de conseguir tanto y por esto quiero que agradecer a mi supervisor Agustín Mihi. Muchos momentos fáciles y menos fáciles han marcado mi doctorado. Me has dado la oportunidad de saltar fuera de mi zona de confort con la gran oportunidad de crecer tanto científicamente que como persona. He aprendido mucho y me llevaré muchas buenas lecciones. Quiero también dar las gracias al Prof.
    [Show full text]
  • Spaser Or Plasmonic Nanolaser?
    Nanophotonics 2021; aop Perspective Cun-Zheng Ning* Spaser or plasmonic nanolaser? – Reminiscences of discussions and arguments with Mark Stockman https://doi.org/10.1515/nanoph-2021-0291 using, instead of nanowires, sub-wavelength-size wires of Received June 9, 2021; accepted June 28, 2021; diameters on the order of 500 nm or larger. We had been published online July 13, 2021 struggling to shrink the diameter of nanowire lasers because the modes become less confined at smaller diameters [7]. My Abstract: This essay is my reminiscences of many inter- then postdoc, Alex Maslov, and I considered the concept of esting discussions I had with Mark Stockman over the coating our nanowires with silver to use the surface plasmon years, mostly around the spaser, its meaning, and its polariton (SPP) modes instead of pure dielectric modes, relationship with plasmonic nanolasers. which are always limited by the diffraction limit. Despite the Keywords: nanolaser; plasmonics; semiconductor laser; initial skepticism from my laser colleagues, Alex’s simula- spaser. tion showed promising results [8]: our semiconductor-metal core–shell structure was shown to support SPP modes for The sad news of Mark Stockman’s untimely death shocked structures with core diameter as small as 10s of nm. Most me greatly. Barely a few months earlier, we were still important of all, the optical gain in the semiconductor core communicating regularly on the paper [1] we were writing may overcome the expected large plasmonic loss of the together in celebration of the 10th anniversary of the first shell. Our next task was to conformally coat a layer of silver experimental realizations [2–4] of the spaser, a landmark onto semiconductor nanowires to form a shell; part of this invention first proposed by Bergman and Stockman in work was in collaboration with Peidong Yang from Berkeley 2003 [5]! within our then DARPA NACHOS (Nanoscale Architectures I first met Mark shortly after the publication of the now for Coherent Hyper-Optic Sources) project.
    [Show full text]
  • Magneto-Optical Spaser
    Magneto-optical spaser D. G. Baranov,1,2 A. P. Vinogradov,1,2 A. A. Lisyansky,3,* Yakov M. Strelniker,4 and David J. Bergman5 1Moscow Institute of Physics and Technology, 9 Institutskiy per., Dolgoprudniy 141701, Moscow Reg., Russia 2Institute for Theoretical and Applied Electromagnetics, 13 Izhorskaya, Moscow 125412, Russia 3Department of Physics, Queens College of the City University of New York, Queens, NY 11367, USA 4Department of Physics, Bar-Ilan University, IL-52900 Ramat-Gan, Israel 5Raymond and Beverly Sackler School of Physics and Astronomy, Faculty of Exact Sciences, Tel Aviv University, IL-69978 Tel Aviv, Israel *Corresponding author: [email protected] We present an electrodynamical model of a novel quantum plasmonic device – magneto- optical (MO) spaser. It is shown that a spherical gain nanoparticle coated with a metallic MO shell can operate as a spaser amplifying circularly polarized surface plasmons. The MO spaser may be used in design of optical isolator in plasmonic transmission lines as well as in spaser spectrometry of chiral molecules. Recently, nanosources of coherent light have attracted significant attention [1]. After Ref. [2], different plasmonic-based light sources have been studied theoretically [3–5] and realized experimentally [6–8]. In most cases, such a light source is a pumped optical emitter (a quantum dot or an active molecule) placed inside or near a plasmonic resonator. For the case of a metallic nanoparticle, such a coupled system represents a SPASER, whose properties have been studied in details during the last decade [2, 9–12]. However, to the best of our knowledge, radiation from all suggested sources is linearly polarized.
    [Show full text]
  • Spaser Based on Graphene Tube
    Scientia Iranica D (2020) 27(6), 3084{3095 Sharif University of Technology Scientia Iranica Transactions D: Computer Science & Engineering and Electrical Engineering http://scientiairanica.sharif.edu Spaser based on graphene tube S. Behjati Ardakani and R. Faez Department of Electrical Engineering, Sharif University of Technology, Azadi Avenue, Tehran, Iran. Received 23 January 2018; received in revised form 11 December 2018; accepted 4 February 2019 KEYWORDS Abstract. This study proposes a structure for graphene spaser (surface plasmon ampli cation by stimulated emission of radiation) and develops an electrostatic model for Plasmonics; quantizing plasmonic modes. Using this model, one can analyze any spaser consisting of Graphene; graphene in the electrostatic regime. The proposed structure is investigated analytically Spaser; and the spasing condition is derived. We show that spasing can occur at some frequencies Quantum optics; where the quality factor of plasmonic modes is higher than some particular minimum Quantum wire. values. Finally, an algorithmic design procedure is proposed by which one can design a viable structure at a given frequency. As an example, a spaser with plasmon energy of 0.1 eV is designed. © 2020 Sharif University of Technology. All rights reserved. 1. Introduction smaller than their wavelengths. In 2003, Stockman and Bergman published the rst paper about the idea and Spaser, as its name suggests, is a counterpart of laser introduced the word spaser to the literature [1]. Since in sub-wavelength dimensions. The di erence between then, many people and groups have focused on ana- spaser and laser is that the latter emits photons, while lyzing and realizing the spaser.
    [Show full text]