Bose-Einstein Condensation of Photons in VCSELs – New Operation Mode of Semiconductor Lasers

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B3 R5220

This talk presents findings on Bose-Einstein condensation of photons within a well-known semiconductor device - the VCSEL.

Photons were the first bosons described by Bose-Einstein statistics. Despite this, they were among the last quantum gases to be Bose-Einstein condensed under controlled conditions, achieved in a microcavity using a rhodamine solution [1]. Since these early experiments, the idea that light thermalization and condensation in optical cavities could occur more broadly has been anticipated. However, Bose-Einstein condensation differs from the typical view of laser operation, which is usually seen as a nonequilibrium process.

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In this talk, I will share our findings on Bose-Einstein condensation of photons within a well-known semiconductor device - the VCSEL [2]. I will start by explaining the physics of light thermalization and condensation in semiconductor laser cavities [3]. Then, I will discuss our measurements showing Bose-Einstein condensation behavior as the system exceeds the critical phase-space density, including the thermalized photon distribution in the condensate. The spectroscopic and thermodynamic properties we observed align with the predicted effects of a Bose-Einstein condensate (BEC) phase transition in thermal equilibrium.

Additionally, I will explore our latest efforts to understand the thermodynamics of photon BEC, particularly to explain the measured temperatures of the photon gas, which differ significantly from the device's. This will be discussed within the framework of the three-temperature model, in which the photon BEC is not in full thermal and chemical equilibrium with the device but rather arises from a dynamical equilibrium with electrons and lattice phonons in the steady state. Our results provide new insights into the operating principles of semiconductor lasers and hold promise for future technological advancements in laser technology [4].

References

  1. J. Klaers et al., Nature 468, 545–548 (2010)
  2. M. Pieczarka et al., Nature Photonics 18, 1090–1096 (2024)
  3. A. Loirette-Pelous,  & J.-J. Greffet, Laser Photonics Rev., 17, 2300366. (2023)
  4. A. Fainstein & G. Usaj, Nature Photonics 18, 999–1001 (2024)

Presenters

Maciej Pieczarka, Associate Professor, Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology (WrocławTech)

Brief Biography

Maciej Pieczarka, associate professor of Wrocław University of Science and Technology (WrocławTech), is a researcher specializing in quantum fluids of light, with a focus on the fundamental physics and applications of exciton–polariton systems in semiconductor microcavities and photon Bose-Einstein condensation in semiconductor lasers. His work explores collective quantum phenomena such as condensation, superfluidity, coherence, and nonlinear dynamics in driven–dissipative photonic platforms.

He is a graduate of WrocławTech, where he completed his Ph.D. and habilitation theses. He has also worked for several years at the Australian National University, in the polariton research group of Prof. Elena Ostrovskaya. He has received several scientific awards and scholarships in Poland, including the Foundation for Polish Science START, the Ministry of Science Award, and multiple National Science Centre grants.