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.
展开▼
