Abstract Photon Bose–Einstein condensation and photon thermalisation have been largely studied with molecular gain media in optical cavities. However, their observation with semiconductors has remained elusive despite a large body of experimental results and very well established theoretical models. In this work, these models are used to build a new theoretical framework that enables revisiting lasing to compare with photon Bose–Einstein condensation in the driven‐dissipative regime. The thermalisation figures of merit and the different experimental procedures to asses thermalization are discussed. Finally, the fluctuations of the system and their relation to the different regimes are explored.Abstract Photon Bose–Einstein condensation and photon thermalisation have been largely studied with molecular gain media in optical cavities. However, their observation with semiconductors has remained elusive despite a large body of experimental results and very well established theoretical models. In this work, these models are used to build a new theoretical framework that enables revisiting lasing to compare with photon Bose–Einstein condensation in the driven‐dissipative regime. The thermalisation figures of merit and the different experimental procedures to asses thermalization are discussed. Finally, the fluctuations of the system and their relation to the different regimes are explored.

arXiv:2301.13073Laser & Photonics ReviewAug 6, 20239 citations

Photon thermalization and Bose condensation via laser cooling of atoms

Chiao-Hsuan Wang, Michael J. Gullans, J. V. Porto +2 more

Bulletin of the American Physical SocietyMar 6, 20180 citations

Bose–Einstein condensation of light in a semiconductor quantum well microcavity

Ross C. Schofield, Ming Fu, Edmund Clarke +9 more

Abstract When particles with integer spin accumulate at low temperature and high density, they undergo Bose–Einstein condensation (BEC). Atoms, magnons, solid-state excitons, surface plasmon polaritons and excitons coupled to light exhibit BEC, which results in high coherence due to massive occupation of the respective system’s ground state. Surprisingly, photons were shown to exhibit BEC recently in organic-dye-filled optical microcavities, which—owing to the photon’s low mass—occurs at room temperature. Here we demonstrate that photons within an inorganic semiconductor microcavity also thermalize and undergo BEC. Although semiconductor lasers are understood to operate out of thermal equilibrium, we identify a region of good thermalization in our system where we can clearly distinguish laser action from BEC. Semiconductor microcavities are a robust system for exploring the physics and applications of quantum statistical photon condensates. In practical terms, photon BECs offer their critical behaviour at lower thresholds than lasers. Our study shows two further advantages: the lack of dark electronic states in inorganic semiconductors allows these BECs to be sustained continuously; and quantum wells offer stronger photon–photon scattering. We measure an unoptimized interaction parameter ( $\tilde{{{{{g}}}}}$ g ̃ ≳ 10–3), which is large enough to access the rich physics of interactions within BECs, such as superfluid light.Abstract When particles with integer spin accumulate at low temperature and high density, they undergo Bose–Einstein condensation (BEC). Atoms, magnons, solid-state excitons, surface plasmon polaritons and excitons coupled to light exhibit BEC, which results in high coherence due to massive occupation of the respective system’s ground state. Surprisingly, photons were shown to exhibit BEC recently in organic-dye-filled optical microcavities, which—owing to the photon’s low mass—occurs at room temperature. Here we demonstrate that photons within an inorganic semiconductor microcavity also thermalize and undergo BEC. Although semiconductor lasers are understood to operate out of thermal equilibrium, we identify a region of good thermalization in our system where we can clearly distinguish laser action from BEC. Semiconductor microcavities are a robust system for exploring the physics and applications of quantum statistical photon condensates. In practical terms, photon BECs offer their critical behaviour at lower thresholds than lasers. Our study shows two further advantages: the lack of dark electronic states in inorganic semiconductors allows these BECs to be sustained continuously; and quantum wells offer stronger photon–photon scattering. We measure an unoptimized interaction parameter ( $$\tilde{{{{{g}}}}}$$ g ̃ ≳ 10–3), which is large enough to access the rich physics of interactions within BECs, such as superfluid light.

Nature PhotonicsAug 12, 202421 citations

Thermalization and Bose-condensation of photons via laser cooling of cold atoms

Chiao-Hsuan Wang, Michael J. Gullans, J. V. Porto +3 more

Bulletin of the American Physical SocietyJun 1, 20180 citations

Bose-Einstein Condensation of Light in a Semiconductor Quantum Well Microcavity

Ross C. Schofield, Fu, Ming, Edmund Clarke +8 more

When particles with integer spin accumulate at low temperature and high density they undergo Bose-Einstein condensation (BEC). Atoms, solid-state excitons and excitons coupled to light all exhibit BEC, which results in high coherence due to massive occupation of the respective system's ground state. Surprisingly, photons were shown to exhibit BEC much more recently in organic dye-filled optical microcavities, which, owing to the photon's low mass, occurs at room temperature. Here we demonstrate that photons within an inorganic semiconductor microcavity also thermalise and undergo BEC. Although semiconductor lasers are understood to operate out of thermal equilibrium, we identify a region of good thermalisation in our system where we can clearly distinguish laser action from BEC. Based on well-developed technology, semiconductor microcavities are a robust system for exploring the physics and applications of quantum statistical photon condensates. Notably, photon BEC is an alternative to exciton-based BECs, which dissociate under high excitation and often require cryogenic operating conditions. In practical terms, photon BECs offer their critical behaviour at lower thresholds than lasers. Our study shows two further advantages of photon BEC in semiconductor materials: the lack of dark electronic states allows these BECs to be sustained continuously; and semiconductor quantum wells offer strong photon-photon scattering. We measure an unoptimised interaction parameter, $\tilde{g}=0.0023\pm0.0003$ , which is large enough to access the rich physics of interactions within BECs, such as superfluid light or vortex formation.When particles with integer spin accumulate at low temperature and high density they undergo Bose-Einstein condensation (BEC). Atoms, solid-state excitons and excitons coupled to light all exhibit BEC, which results in high coherence due to massive occupation of the respective system's ground state. Surprisingly, photons were shown to exhibit BEC much more recently in organic dye-filled optical microcavities, which, owing to the photon's low mass, occurs at room temperature. Here we demonstrate that photons within an inorganic semiconductor microcavity also thermalise and undergo BEC. Although semiconductor lasers are understood to operate out of thermal equilibrium, we identify a region of good thermalisation in our system where we can clearly distinguish laser action from BEC. Based on well-developed technology, semiconductor microcavities are a robust system for exploring the physics and applications of quantum statistical photon condensates. Notably, photon BEC is an alternative to exciton-based BECs, which dissociate under high excitation and often require cryogenic operating conditions. In practical terms, photon BECs offer their critical behaviour at lower thresholds than lasers. Our study shows two further advantages of photon BEC in semiconductor materials: the lack of dark electronic states allows these BECs to be sustained continuously; and semiconductor quantum wells offer strong photon-photon scattering. We measure an unoptimised interaction parameter, $\tilde{g}=0.0023\pm0.0003$, which is large enough to access the rich physics of interactions within BECs, such as superfluid light or vortex formation.

arXiv:2306.15314Jun 27, 20230 citations

Bose-Einstein condensation of photons thermalized with gaseous medium inside cavity

Alexander Kruchkov

Jan 2, 20140 citations

\tilde{{{{{g}}}}}

g ̃ ≳ 10–3), which is large enough to access the rich physics of interactions within BECs, such as superfluid light.

\tilde{g}=0.0023\pm0.0003

, which is large enough to access the rich physics of interactions within BECs, such as superfluid light or vortex formation.