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

Journal of Physics Condensed Matter

Optical bistability in an electron-hole system: the effect of phonons

S. Mohapatro, Sukanta Kumar Tripathy, G. S. Tripathi, J. N. Mohanty

Published Oct 11, 1993• 4 citations
Publisher

Abstract

We consider an electron-hole system illuminated by a laser and show that the system shows bistable and multistable behaviours. The mechanisms responsible for these behaviours are discussed in terms of excitonic and phonon interactions. It is found that both the excitonic and the phonon effects contribute to the multistability in the system. With an increase in the strength of the phonon interactions, the system passes from a phase of multistability to a phase of bistability; the reverse happens as the strength of the electron-hole interaction increases.

DOI
10.1088/0953-8984/5/41/011

Related papers

Optical bistability and related phase transitions in an electron–hole system

G. S. Tripathi, Subrat K. Shadangi, Sukanta K. Tripathy +1 more

Abstract Optical bistability (OB) is a phenomenon that describes a light induced phase transition in the non-equilibrium state. It is vital for all-optical computing and communication, serving as the basis for switches, logic gates, transistors, and memory. By enabling two stable light states, OB allows storage and fast switching, making high-speed, energy-efficient data processing possible. In this work we study the phenomenon in a two-band semiconductor in an optical cavity. Starting from a many-body Hamiltonian of optically generated electrons, holes and light-semiconductor interaction and Coulomb electron–electron, hole–hole and electron–hole interactions, we obtain the optical Bloch equations, in the mean field approximation, where relaxation is included phenomenologically. We obtain expressions for particle density, excitonic pair density and output intensity as non-linear functions of input light intensity. All these quantities show bistable behaviour, with two stable phases, and hysteresis in the non-equilibrium state. Equilibrium is ensured by introducing damping terms for the particle density amplitude, excitonic density amplitude, and cavity photon amplitude phenomenologically. The electron–hole pairs increase with light intensity, shows bistable features and then disappears with further increase in the input light intensity. The bistable behaviour becomes pronounced as we pass from low Coulomb interaction strengths to high Coulomb interaction strengths between electrons and holes. For sub-bandgap excitations, the output light versus incident light shows a complex behaviour.

Physica Scripta•May 27, 2026•0 citations

Exciton–Phonon Mechanism of Optical Bistability

Bohdan M. Nitsovich, O. V. Krechivskii, G. M. Pestryakov

Abstract A joint effect of exciton–phonon and exciton–exciton interactions on optical properties of semiconductors is studied. In these substances the exciton density is shown to be a multivalued function of incident light intensity and the frequency and temperature conditions under which the optical bistability arises are specified. Investigation of nonlinear optical properties of semiconductors with account for the indirect phototransitions exhibits that both multistable optical states and the bistable ones distinguished by a complicated dynamics of the switching may be observed in such systems.

physica status solidi (b)•Dec 1, 1988•2 citations

Theory of optical bistability in the region of exciton resonances

Bohdan M. Nitsovich, C. Y. Zenkova

An exciton-phonon mechanism for producing cavityless optical bistability is suggested. We consider the influence of the oscillating subsystem of a crystal on the absorption process of a laser wave in the region of exciton frequencies. It is shown that exciton-phonon interaction leads to nonlinear dependence of the absorption coefficient on the density of the exciton gas. The increase of absorption with increasing exciton density, however, is possible only in the frequency region on the long-wavelength tail of the exiton band. As a result, the exciton density of the crystal becomes a hysteresis function of external parameters (intensity of the incident wave, temperature, etc.). We calculate the absorption coefficient of excitons and define the frequency and temperature regions where optical bistability may exist. We analyze different relaxation mechanisms of excitons and explain the experimental results of observing optical bistability in different semiconductor crystals.

Optical Engineering•Apr 1, 1995•11 citations

External optical feedback for exciton-phonon systems in optical cavities

X. Li, W. Cai, Roberta Marani +1 more

Effects of external optical feedback on the behavior of input-cavity-field relations are investigated for an electron–phonon system inside an optical cavity exposed to an incident laser field. The external feedback by conventional mirrors and by phase-conjugate mirrors is considered separately. Steady-state results are obtained numerically for a typical phonon–exciton material of polydiacetylene. In the case of conventional external feedback, the threshold, the contrast, and the switching behavior of optical bistability can be changed by adjustment of the feedback parameters without causing any instability, whereas in the case of phase-conjugate feedback the cavity field intensity shows five states corresponding to a single input field intensity as long as the feedback is strong enough. However, all these states are unstable because of the amplified phase-conjugate reflection, which limits the application of phase-conjugate mirrors in optical multistabilities.

Journal of the Optical Society of America B•Sep 1, 1994•0 citations

Temperature variation of optical bistability of a semiconductor

Bohdan M. Nitsovich, V. N. Vivcharyuk, I. M. Grigorashuk

The effect of the phonon subsystem of a crystal on laser absorption is considered. The exciton- phonon interaction is shown to result in a nonlinear behavior of absorption as a function of exciton gas density. The output light intensity is calculated as a function of temperature and the temperature range in which optical bistability occurs is established.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Dec 10, 1993•0 citations

Phonon-mediated excitonic optical bistability in polymers

X. S. Li, D. L. Lin, Thomas F. George +1 more

For a polymer inside an optical cavity, optical multistability mediated by phonon modes and virtual exciton coupling is investigated. The cavity field, excitons, and phonon modes are treated as damped oscillators, and the equations of motion for the dynamical variables are obtained by applying Dekker's theory for dissipative systems. Steady-state results are obtained numerically for polydiacetylene [bis(p-toluene sulfonate)] with the input field frequency on or off resonance with the cavity field. The variation of the cavity-field intensity follows a reversed hysteresis loop on resonance, while it may follow either a normal or a reversed hysteresis loop off resonance depending on the course of change of the driving-field intensity at the unstable turning point. The variation is inverted when the detuning changes its sign. It is also found that the virtual excitons, phonon modes, and feedback of the cavity are all indispensable to such tristability.

Physical review. B, Condensed matter•Aug 15, 1990•11 citations
We consider an electron-hole system illuminated by a laser and show that the system shows bistable and multistable behaviours. The mechanisms responsible for these behaviours are discussed in terms of excitonic and phonon interactions. It is found that both the excitonic and the phonon effects contribute to the multistability in the system. With an increase in the strength of the phonon interactions, the system passes from a phase of multistability to a phase of bistability; the reverse happens as the strength of the electron-hole interaction increases.
Abstract Optical bistability (OB) is a phenomenon that describes a light induced phase transition in the non-equilibrium state. It is vital for all-optical computing and communication, serving as the basis for switches, logic gates, transistors, and memory. By enabling two stable light states, OB allows storage and fast switching, making high-speed, energy-efficient data processing possible. In this work we study the phenomenon in a two-band semiconductor in an optical cavity. Starting from a many-body Hamiltonian of optically generated electrons, holes and light-semiconductor interaction and Coulomb electron–electron, hole–hole and electron–hole interactions, we obtain the optical Bloch equations, in the mean field approximation, where relaxation is included phenomenologically. We obtain expressions for particle density, excitonic pair density and output intensity as non-linear functions of input light intensity. All these quantities show bistable behaviour, with two stable phases, and hysteresis in the non-equilibrium state. Equilibrium is ensured by introducing damping terms for the particle density amplitude, excitonic density amplitude, and cavity photon amplitude phenomenologically. The electron–hole pairs increase with light intensity, shows bistable features and then disappears with further increase in the input light intensity. The bistable behaviour becomes pronounced as we pass from low Coulomb interaction strengths to high Coulomb interaction strengths between electrons and holes. For sub-bandgap excitations, the output light versus incident light shows a complex behaviour.
Abstract A joint effect of exciton–phonon and exciton–exciton interactions on optical properties of semiconductors is studied. In these substances the exciton density is shown to be a multivalued function of incident light intensity and the frequency and temperature conditions under which the optical bistability arises are specified. Investigation of nonlinear optical properties of semiconductors with account for the indirect phototransitions exhibits that both multistable optical states and the bistable ones distinguished by a complicated dynamics of the switching may be observed in such systems.
An exciton-phonon mechanism for producing cavityless optical bistability is suggested. We consider the influence of the oscillating subsystem of a crystal on the absorption process of a laser wave in the region of exciton frequencies. It is shown that exciton-phonon interaction leads to nonlinear dependence of the absorption coefficient on the density of the exciton gas. The increase of absorption with increasing exciton density, however, is possible only in the frequency region on the long-wavelength tail of the exiton band. As a result, the exciton density of the crystal becomes a hysteresis function of external parameters (intensity of the incident wave, temperature, etc.). We calculate the absorption coefficient of excitons and define the frequency and temperature regions where optical bistability may exist. We analyze different relaxation mechanisms of excitons and explain the experimental results of observing optical bistability in different semiconductor crystals.
Effects of external optical feedback on the behavior of input-cavity-field relations are investigated for an electron–phonon system inside an optical cavity exposed to an incident laser field. The external feedback by conventional mirrors and by phase-conjugate mirrors is considered separately. Steady-state results are obtained numerically for a typical phonon–exciton material of polydiacetylene. In the case of conventional external feedback, the threshold, the contrast, and the switching behavior of optical bistability can be changed by adjustment of the feedback parameters without causing any instability, whereas in the case of phase-conjugate feedback the cavity field intensity shows five states corresponding to a single input field intensity as long as the feedback is strong enough. However, all these states are unstable because of the amplified phase-conjugate reflection, which limits the application of phase-conjugate mirrors in optical multistabilities.
For a polymer inside an optical cavity, optical multistability mediated by phonon modes and virtual exciton coupling is investigated. The cavity field, excitons, and phonon modes are treated as damped oscillators, and the equations of motion for the dynamical variables are obtained by applying Dekker's theory for dissipative systems. Steady-state results are obtained numerically for polydiacetylene [bis(p-toluene sulfonate)] with the input field frequency on or off resonance with the cavity field. The variation of the cavity-field intensity follows a reversed hysteresis loop on resonance, while it may follow either a normal or a reversed hysteresis loop off resonance depending on the course of change of the driving-field intensity at the unstable turning point. The variation is inverted when the detuning changes its sign. It is also found that the virtual excitons, phonon modes, and feedback of the cavity are all indispensable to such tristability.