摘要
A room-temperature cw operation of a tunable external cavity(EC)quantum cascade laser(QCL)at an emitting wavelength of 4.6µm is presented.Strain−compensation combined with two-phonon resonance in an active region design promises low threshold current density.A very low threshold current density of 1.47 kA/cm^(2) for an EC−QCL operated in cw mode is realized.Single-mode cw operation with a side-mode suppression ratio of 20 dB and a wide tuning range of over 110 cm-1 are achieved.Moreover,an even wider tuning range of over 135 cm^(−1) is obtained in pulsed mode at room temperature.
基金
by the National Natural Science Foundation of China under Grant Nos 60736031,60806018 and 60906026
the National Basic Research Program of China under Grant No 2006CB604903
the National High Technology Research and Development Program of China under Grant Nos 2007AA03Z446 and 2009AA03Z403.
