Title: Interband Cascade Lasers: from concept to devices and applications

　　Speaker: Prof. Rui Q. Yang(University of Oklahoma，USA)

　　Time: 9:30(AM), Dec.29, 2009

　　Venue:  Academic Meeting Room, Institute of Semiconductors, CAS

　　Abstract: Interband cascade (IC) lasers take advantage of the broken band-gap alignment in type-II quantum wells to reuse injected electrons in cascade stages for photon generation with high quantum efficiency and represent a relatively new class of mid-infrared light sources. Unlike intraband quantum cascade lasers, IC lasers use interband transitions for photon emission without involving fast phonon scattering, making it possible to significantly lower the threshold current density. IC lasers are

　　designed entirely based on quantum mechanics and grown by advanced technology such as molecular beam epitaxy (MBE). IC lasers offer a wide wavelength tailoring range without being limited by the conduction-band offset in the wavelength region of 3-4 micron where there are hydrocarbon signatures important for life detection in space exploration. Since the proposal of IC lasers in 1994 and the first demonstration in 1997, significant progress has been achieved toward high-performance mid-IR laser devices. Some outstanding performance features such as low threshold current densities (e.g. <2 A/cm2 at 80 K, <400A/cm2 at 300K) and high cw wall-plug efficiency (e.g. >31% at 80 K) partially verified the advantages of IC lasers. Single-mode distributed feedback (DFB) IC lasers have been demonstrated in cw operation for the wavelength range from ~3.2 to 3.6 μm. These DFB IC lasers have been employed for the detection of gases such as methane (CH4), Ethane (C2H6), hydrogen chloride (HCl), and formaldehyde (H2CO), and have been flown on aircraft and high-altitude balloon instruments and measured atmospheric CH4 and HCl profiles. In this talk, the development of mid-infrared IC lasers from concept to devices and applications will be reviewed. Their current status and future prospects will be discussed. If time permits, our recent results of photodetectors using IC structures will be presented.

　　About speaker：

　　Rui Q. Yang received the B.Sc. degree in physics from Zhejiang University in 1982, and the M.Sc. and Ph.D. degrees in physics from Nanjing University in 1984 and 1987, respectively. He is the inventor of interband cascade lasers with research activities ranging from condensed matter physics to semiconductor quantum devices such as tunneling diodes, mid-infrared lasers and detectors. Prior to joining OU as a professor in 2007, he was a Principal Member of Engineering Staff and a Task Manager at the Jet Propulsion Laboratory (JPL) in California, where he led the development of advanced mid-IR IC lasers for applications in Earth sciences and planetary explorations. He received the Edward Stone Award in 2007 from JPL for outstanding research publication and the successful accelerated infusion of cutting-edge interband cascade semiconductor laser technology into flight mission readiness.