High-temperature distributed feedback quantum cascade lasers with wide tuning range wavelength

In this paper, high performance of distributed feedback quantum cascade lasers operation at 7.7 ¿m and 8.4 ¿m have been investigated. With a broad gain spectrum, the DFB QCLs employing different grating periods exhibit a wavelength span of 0.17 ¿m at room temperature and total wavelength coverage of 0.33 ¿m at various heatsink temperatures. For the 8.4 ¿m DFB-QCLs with a high side mode suppression ratio of about 30 dB, a low threshold current density of 1.73 kA/cm
²
at 300 K and a high operating temperature of 420 K are achieved in pulsed mode. The DFB-QCLs emission at 7.7 ¿m have been successfully used in N
₂
O absorption line detection.