Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physical Review A

Backward-stimulated emission and nonreciprocity in optics

Ming Lai, Jean‐Claude Diels

Published Mar 1, 1991• 1 citation
Publisher

Abstract

Conditions for enhanced backward-stimulated emission are formulated for a thin layer of gain medium. A comparison is made between the enhanced backward-stimulated emission and the reflection from a dielectric film. A type of nonreciprocal reflective structure using a gain layer and a dielectric film is described. Such a device can be used to construct ring lasers with controllable unidirectional operation.

DOI
10.1103/physreva.43.2464

Related papers

Optically nonreciprocal device exploiting enhanced backward-stimulated emission

Ming Lai, Jean‐Claude Diels

The physical nature of the backward-stimulated emission can be understood by considering the angular distribution of the total radiation from a set of atomic dipoles driven by an intense laser beam. From the classical point of view, the backward-stimulated emission is simply a reflection from the interface between a dielectric and a gain medium from the mismatch in the imaginary parts of their indices of refraction. For bulk gain structure, backward-stimulated emission is usually too weak to be noticed. However, in the case of a gain layer much thinner than a wavelength or a periodic thin gain structure with a spacing of λ/2, the backward-stimulated emission is enhanced and can be as large as the forward stimulated emission in terms of the amplitude of radiation field.1

Quantum Electronics and Laser Science Conference•May 12, 1991•0 citations

Stimulated emission in vicinity of the critical angle

J. K. Asane, Md Golam Rabbani Chowdhury, Kanij Mehtanin Khabir +2 more

We have demonstrated amplified spontaneous emission (ASE) propagating along the planar interface between two adjacent dielectrics with slightly different refractive indexes. This emission originates from the leaky mode, fueled by optical gain in the low-index dielectric, that is outcoupled to the high-index dielectric in vicinity of the critical angle for total internal reflection. This led us to the observation of spectacular concentric rings of ASE emission occurring above the low and soft stimulated emission threshold. The results of our study can be used to develop novel miniature low-threshold stimulated emission sources and photonic circuits operating at optical frequencies.

Applied Physics Letters•Jul 19, 2021•2 citations

Stimulated emission due to Doppler-free transitions in optically pumped lasers

A. K. Popov, Vladimir M. Shalaev

An analysis is made of conditions for achieving amplification due to transitions whose Doppler broadening is eliminated (under optical pumping) by light shifts which depend on the atomic velocity. An investigation is made of the spectral characteristics of this amplification process and of the features of lasing due to these transitions. The advantages of lasing due to this type of pumping are shown and possibilities for achieving unidirectional lasing in ring resonators are indicated.

Soviet Journal of Quantum Electronics•Mar 31, 1982•2 citations

Electromagnetic propagation in a photorefractive layered medium

Pochi Yeh

The propagation of electromagnetic radiation in a photorefractive layered medium is considered. The forward-and backward-propagating waves are coupled in the photorefractive material. This coupling is asymmetrical and leads to a nonreciprocal optical transmission. The reflectance and the transmittance are derived and discussed.

Journal of the Optical Society of America•Oct 1, 1983•23 citations

The single-mode laser

L. Mandeļ, E. Wolf

Introduction The idea of making use of the phenomenon of stimulated emission from an atom or molecule for amplification of the electromagnetic field, and then combining the amplifier with a resonator to make an oscillator, is due to Townes and his co-workers (Gordon, Zeiger and Townes, 1954, 1955) and independently to Basov and Prokhorov (1954, 1955). The former constructed the first MASER, or microwave amplifier by stimulated emission of radiation . In 1958 Schawlow and Townes proposed an application of the same principle to the optical domain (Schawlow and Townes, 1958), in which a two-mirror Fabry–Perot interferometer serves as the optical resonator and an excited group of atoms as the gain medium. The first LASER, or light amplifier by stimulated emission of radiation , was constructed by Maiman (1960). The gain medium was ruby, which was excited by a bright flash of light from a gas discharge tube, whereupon the laser delivered a short optical pulse. The first continuously operating – or CW – laser was developed by Javan and his co-workers (Javan, Bennett and Herriott, 1961); it made use of a He:Ne gas mixture, that was continuously excited by a discharge, as the gain medium. This type of laser is still widely used today. Since that time many different kinds of laser have been developed, ranging in wavelength from the infrared to the ultraviolet. Some produce light at several different frequencies at once, and some are tunable over a wide range.

Cambridge University Press eBooks•Sep 29, 1995•0 citations

Optical Gain and Lasers

Gabriel Laufer

Introduction Previous discussions (see Section 10.4) suggested that stimulated emission can be used to generate optical gain, that is, to amplify radiation. The reader certainly has experience in the amplification of electronic signal. For example, radio receivers capture faint radio waves and turn them into a signal that is powerful enough to drive large speakers. This electronic amplification increases the amplitude of the signal while faithfully preserving its acoustic frequencies and modulation characteristics. Similarly, optical amplification is expected to increase the amplitude of an optical signal while preserving its frequency, its modulation characteristics, and its coherence. The latter requirement is of particular significance for optical radiation, where the coherence of naturally occurring radiation rarely exceeds one micrometer. Lasers are the primary source for coherent radiation. They depend on stimulated emission for amplification and for the generation of coherent radiation (the word laser is the acronym of Light Amplification by Stimulated Emission of Radiation). For amplification, an atomic system that is part of the laser medium must be prepared with a sufficiently large number of particles in the excited state. (The term atomic system is used here to describe all microscopic systems including molecules and free electrons.) Radiation passing through that excited medium encounters multiple events of stimulated emission, each event contributing one photon that is added coherently to the propagating beam. When the number of events of stimulated emission exceed all losses by absorption or scattering, the incident radiation is amplified.

Cambridge University Press eBooks•Jul 13, 1996•0 citations
Conditions for enhanced backward-stimulated emission are formulated for a thin layer of gain medium. A comparison is made between the enhanced backward-stimulated emission and the reflection from a dielectric film. A type of nonreciprocal reflective structure using a gain layer and a dielectric film is described. Such a device can be used to construct ring lasers with controllable unidirectional operation.
The physical nature of the backward-stimulated emission can be understood by considering the angular distribution of the total radiation from a set of atomic dipoles driven by an intense laser beam. From the classical point of view, the backward-stimulated emission is simply a reflection from the interface between a dielectric and a gain medium from the mismatch in the imaginary parts of their indices of refraction. For bulk gain structure, backward-stimulated emission is usually too weak to be noticed. However, in the case of a gain layer much thinner than a wavelength or a periodic thin gain structure with a spacing of λ/2, the backward-stimulated emission is enhanced and can be as large as the forward stimulated emission in terms of the amplitude of radiation field.1
We have demonstrated amplified spontaneous emission (ASE) propagating along the planar interface between two adjacent dielectrics with slightly different refractive indexes. This emission originates from the leaky mode, fueled by optical gain in the low-index dielectric, that is outcoupled to the high-index dielectric in vicinity of the critical angle for total internal reflection. This led us to the observation of spectacular concentric rings of ASE emission occurring above the low and soft stimulated emission threshold. The results of our study can be used to develop novel miniature low-threshold stimulated emission sources and photonic circuits operating at optical frequencies.
Introduction The idea of making use of the phenomenon of stimulated emission from an atom or molecule for amplification of the electromagnetic field, and then combining the amplifier with a resonator to make an oscillator, is due to Townes and his co-workers (Gordon, Zeiger and Townes, 1954, 1955) and independently to Basov and Prokhorov (1954, 1955). The former constructed the first MASER, or microwave amplifier by stimulated emission of radiation . In 1958 Schawlow and Townes proposed an application of the same principle to the optical domain (Schawlow and Townes, 1958), in which a two-mirror Fabry–Perot interferometer serves as the optical resonator and an excited group of atoms as the gain medium. The first LASER, or light amplifier by stimulated emission of radiation , was constructed by Maiman (1960). The gain medium was ruby, which was excited by a bright flash of light from a gas discharge tube, whereupon the laser delivered a short optical pulse. The first continuously operating – or CW – laser was developed by Javan and his co-workers (Javan, Bennett and Herriott, 1961); it made use of a He:Ne gas mixture, that was continuously excited by a discharge, as the gain medium. This type of laser is still widely used today. Since that time many different kinds of laser have been developed, ranging in wavelength from the infrared to the ultraviolet. Some produce light at several different frequencies at once, and some are tunable over a wide range.
Introduction Previous discussions (see Section 10.4) suggested that stimulated emission can be used to generate optical gain, that is, to amplify radiation. The reader certainly has experience in the amplification of electronic signal. For example, radio receivers capture faint radio waves and turn them into a signal that is powerful enough to drive large speakers. This electronic amplification increases the amplitude of the signal while faithfully preserving its acoustic frequencies and modulation characteristics. Similarly, optical amplification is expected to increase the amplitude of an optical signal while preserving its frequency, its modulation characteristics, and its coherence. The latter requirement is of particular significance for optical radiation, where the coherence of naturally occurring radiation rarely exceeds one micrometer. Lasers are the primary source for coherent radiation. They depend on stimulated emission for amplification and for the generation of coherent radiation (the word laser is the acronym of Light Amplification by Stimulated Emission of Radiation). For amplification, an atomic system that is part of the laser medium must be prepared with a sufficiently large number of particles in the excited state. (The term atomic system is used here to describe all microscopic systems including molecules and free electrons.) Radiation passing through that excited medium encounters multiple events of stimulated emission, each event contributing one photon that is added coherently to the propagating beam. When the number of events of stimulated emission exceed all losses by absorption or scattering, the incident radiation is amplified.