Bonn 2025 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

Q: Fachverband Quantenoptik und Photonik

Q 34: In Memoriam of Hermann Haken (joint session Q/MO)

Q 34.2: Invited Talk

Wednesday, March 12, 2025, 11:30–12:00, HS I PI

Bose-Einstein condensation of photons in vertical-cavity surface-emitting lasers — •Maciej Pieczarka — Wrocław University of Science and Technology, Wrocław, Poland

Professor Haken pioneered the development of the quantum theory of lasers and discovered that lasing action can be viewed as a nonequilibrium second-order phase transition. This visionary and broader view inspired many to find a link between lasing and the Bose-Einstein condensation (BEC) of photons. It appears that the worlds of lasers and BEC are deeply intertwined, as BEC was found in dye-filled microcavities [1] and, more recently, in semiconductor lasers [2].

I will present our demonstration of photon BEC phase transition in a real-world device - a Vertical-Cavity Surface-Emitting Laser (VCSEL) [2]. Besides distinctive differences from the complete thermal equilibrium, we show that photons in a VCSEL follow the equation of state for an ideal bosonic gas. We argue that photon BEC can be a much more common phenomenon in laser physics than previously anticipated.

[1] J. Klaers et al., Nature 468, 545 (2010).

[2] M. Pieczarka et al., Nature Photonics 18, 1090 (2024).

Keywords: Bose-Einstein condensation; vertical-cavity surface-emitting lasers; microcavities; equation of state