Semiconductor Cascade Lasers: From Device Physics to Quantum Optics to Practical Applications

 

In semiconductor cascade lasers, multiple gain stages are connected electrically in series. Each electron injected into a cascade laser is capable of producing more than one photon. In this way, the differential quantum efficiency and the optical signal-to-noise ratio can be made much larger than for conventional semiconductor lasers. Our work on cascade lasers has required us to revise the previous work on laser noise, and develop self-consistent models for the current and photon noise in semiconductor cascade lasers. Photon emission in different gain stages of cascade lasers is highly correlated as a result of macroscopic coulomb effects. These correlations significantly affect the photon noise in the laser output.

In this talk, the theoretical models will be presented along with their experimental confirmation. The experimental work on the realization of interband bipolar cascade lasers and intersubband quantum cascade lasers for telecommunication applications will also be presented. Finally, future prospects for ultra-fast intersubband optical devices will be discussed.

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Biography of Prof. Farhan Rana

Farhan Rana joined the Department of Electrical and Computer Engineering of Cornell University in January 2003. He obtained B.S., M.S., and Ph.D. degrees in Electrical Engineering from the Massachusetts Institute of Technology (MIT). He has worked on a variety of different topics related to semiconductor opto-electronics, quantum optics, and mesoscopic physics during his Ph.D. research. Before staring Ph.D. he had worked at I.B.M.'s Thomas J. Watson Research Center on Silicon field-effect devices and quantum-dot memories.

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