Polaritons

From Portal
Jump to: navigation, search


Polaritons are regions of charge in conjugate pairs.

What is a polariton?
A polariton is a coupled state between a photon and some type of material excitation.

http://www.nature.com/nphoton/journal/v4/n6/full/nphoton.2010.136.html

Designer spoof surface plasmon structures collimate terahertz laser beams

Source: http://www.nature.com/nmat/journal/vaop/ncurrent/abs/nmat2822.html

Nanfang Yu, Qi Jie Wang, Mikhail A. Kats, Jonathan A. Fan, Suraj P. Khanna, Lianhe Li, A. Giles Davies, Edmund H. Linfield & Federico Capasso

Journal name: Nature Materials Year published: (2010) doi:10.1038/nmat2822

Received: 10 March 2010 | Accepted: 30 June 2010 | Published online 08 August 2010

“Surface plasmons have found a broad range of applications in photonic devices at visible and near-infrared wavelengths. In contrast, longer-wavelength surface electromagnetic waves, known as Sommerfeld or Zenneck waves1, 2, are characterized by poor confinement to surfaces and are therefore difficult to control using conventional metallo-dielectric plasmonic structures. However, patterning the surface with subwavelength periodic features can markedly reduce the asymptotic surface plasmon frequency, leading to ‘spoof’ surface plasmons3, 4 with subwavelength confinement at infrared wavelengths and beyond, which mimic surface plasmons at much shorter wavelengths. We demonstrate that by directly sculpting designer spoof surface plasmon structures that tailor the dispersion of terahertz surface plasmon polaritons on the highly doped semiconductor facets of terahertz quantum cascade lasers, the performance of the lasers can be markedly enhanced. Using a simple one-dimensional grating design, the beam divergence of the lasers was reduced from ∼180° to ∼10°, the directivity was improved by over 10 decibels and the power collection efficiency was increased by a factor of about six compared with the original unpatterned devices. We achieve these improvements without compromising high-temperature performance of the lasers.”

Letters to Nature

Nature 414, 731-735 (13 December 2001)
doi:10.1038/414731a

Received 12 June 2001
Accepted 8 October 2001

High-temperature ultrafast polariton parametric amplification in semiconductor microcavities (2001)

M. Saba1, C. Ciuti1, J. Bloch2, V. Thierry-Mieg2, R. André3, Le Si Dang3, S. Kundermann1, A. Mura4, G. Bongiovanni4, J. L. Staehli1 & B. Deveaud1

1. Physics Department, Swiss Federal Institute of Technology Lausanne, PH-Ecublens, CH-1015 Lausanne-EPFL, Switzerland
2. Centre National de la Recherche Scientifique, L2M-CNRS, 92225 Bagneux Cedex, France
3. Laboratoire de Spectrometrie Physique, Université J. Fourier-Grenoble, F-38402 Saint Martin d'Hères Cedex, France
4. Dipartimento di Fisica and Istituto Nazionale di Fisica della Materia, Università degli Studi di Cagliari, I-09042 Monserrato, Italy

Abstract

Cavity polaritons, the elementary optical excitations of semiconductor microcavities, may be understood as a superposition of excitons and cavity photons1. Owing to their composite nature, these bosonic particles have a distinct optical response, at the same time very fast and highly nonlinear. Very efficient light amplification due to polariton–polariton parametric scattering has recently been reported in semiconductor microcavities at liquid-helium temperaturesX2, 3, 4, 5, 6, 7, 8, 9, 10, 11. Here we demonstrate polariton parametric amplification up to 120 K in GaAlAs-based microcavities and up to 220 K in CdTe-based microcavities. We show that the cut-off temperature for the amplification is ultimately determined by the binding energy of the exciton. A 5-microm-thick planar microcavity can amplify a weak light pulse more than 5,000 times. The effective gain coefficient of an equivalent homogeneous medium would be 107 cm-1. The subpicosecond duration and high efficiency of the amplification could be exploited for high-repetition all-optical microscopic switches and amplifiers. 105 polaritons occupy the same quantum state during the amplification, realizing a dynamical condensate of strongly interacting bosons which can be studied at high temperature.

To read this story in full you will need to login [Nature.com account] or make a payment.

Source: http://www.nature.com/nature/journal/v414/n6865/full/414731a.html


Raman scattering by hot and thermal polaritons in crystal quartz (2006)

Journal Il Nuovo Cimento D
Publisher Italian Physical Society
ISSN 0392-6737 (Print) 1826-9893 (Online)
Issue Volume 4, Number 5 / November, 1984
DOI 10.1007/BF02450603
Pages 453-468
Subject Collection Physics and Astronomy
SpringerLink Date Wednesday, August 09, 2006
PDF (725.8 KB)

F. Bogani1, 2, M. Colocci1, 2, M. Neri1, 2 and R. Querzoli1, 2
(1) Dipartimento di Fisica dell'Università, Firenze, Italia
(2) Unità del Gruppo Nazionale di Struttura della Materia, Largo E. Fermi 2, 50125 Firenze, Italia

Received: 30 August 1984

Summary

Nonlinear mixing of IR and visible radiation,i.e. coherent Raman scattering by polaritons driven by a CO2 laser, has been used to obtain the dispersion curve and its width inq-space of the polariton associated to theE-phonon at 1065 cm−1 in crystal quartz. It is shown in this paper that a direct method to determine indipendently, with high precision, the refractive index and absorbance of a crystal can be obtained in this way. The results are compared with accurate data obtained from Raman scattering by polaritions in thermal equilibrium and very good agreement is found between the two measurements. It is finally shown that nonlinear-mixing techniques turn out to be completely consistent with the simple picture of scattering of light by hot polaritons.

PACS. 78.30 Infra-red and Raman spectra and scattering

Source: SpringerLink.com http://www.springerlink.com/content/a772x0885751m6h4/ (full text available)

Physics Letters A
Volume 30, Issue 3, 6 October 1969, Pages 177-178
doi:10.1016/0375-9601(69)90920-7 | How to Cite or Link Using DOI
Copyright © 1969 Published by Elsevier B.V.

Observation of infrared emission from stimulated polaritons in quartz (1969)

S. Biraud-Lavala and G. Chartiera

aInstitut D'Electronique Fondamentale, Laboratoire associé au CNRS Faculté des Sciences, Bâtiment 220, 91-Orsay, France

Received 4 August 1969.
Available online 23 September 2002.


Abstract

Polaritons have been excited from the 1072 cm−1 optical mode of quartz by a two beams method. The electromagnetic part of the excitation (far infrared radiation) has been directly observed, outside the crystal, with a Hg---Te, Cd---Td detector.

Physics Letters A
Volume 30, Issue 3, 6 October 1969, Pages 177-178

Source: ScienceDirect.com http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TVM-46TY13H-3F&_user=10&_coverDate=10%2F06%2F1969&_rdoc=1&_fmt=high&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1413552619&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=1fb9e0d4fdc21e1b4efec55b1e996a4a