RSS icon
Twitter icon
Facebook icon
Vimeo icon
YouTube icon

Superfluorescence from Ultrahigh-Density Magneto-excitons in Quantum Wells

September 26, 2011 - 12:30pm
Speaker: 
Jun Kono
Institution: 
Departments of Electrical & Computer Engineering and Physics & Astronomy, Rice University

The spontaneous appearance of macroscopic coherence is among the most dramatic cooperative phenomena in physics. In quantum electrodynamics, there exists a self-organization process of fundamental importance, called superfluorescence (SF), in which a collection of inverted atoms is incoherently prepared but macroscopic coherence builds up spontaneously. The resultant macroscopic dipole decays superradiantly, producing a burst of coherent radiation. SF has been observed in atomic gases and rarefied impurities in crystals but hitherto unobserved in semiconductors because of ultrafast decoherence. Here, we present experimental evidence for SF through cooperative recombination of ultrahigh-density excitons in semiconductor quantum wells in a strong perpendicular magnetic field. At a critical magnetic field and excitation fluence, we observe a sudden exciton depopulation accompanied by picosecond bursts of radiation. In addition, a clear transition from omnidirectional emission to a randomly directed but highly collimated beam was observed.

1201 Physics Building
College Park, MD 20742

Subscribe to A Quantum Bit 

Quantum physics began with revolutionary discoveries in the early twentieth century and continues to be central in today’s physics research. Learn about quantum physics, bit by bit. From definitions to the latest research, this is your portal. Subscribe to receive regular emails from the quantum world. Previous Issues...

Sign Up Now

Sign up to receive A Quantum Bit in your email!

 Have an idea for A Quantum Bit? Submit your suggestions to jqi-comm@umd.edu