Most vapor molecules have a unique absorption spectrum in the mid-IR region, so this range is of particular interest for trace gas analysis and chemical sensing. And quantum cascade (QC) lasers are ideal candidate light sources for mid-IR spectroscopy: Their emission wavelength reaches from the midto the far-IR with good power efficiency. QC lasers are based on the intersubband transitions betw...

We present investigations of the the relative intensity noise (RIN) of a quantum cascade laser (QC) laser in continuous wave operation. We analyze the intensity noise properties in terms of the relative intensity noise (RIN). In contrast to conventional interband semiconductor diode lasers we obtain a different scaling behavior of RIN with increasing optical output power for QC lasers. From a s...

There is an increasing need in many chemical sensing applications ranging from industrial process control to environmental science and medical diagnostics for fast, sensitive, and selective gas detection based on laser spectroscopy. The recent availability of novel pulsed and CW quantum cascade distributed feedback (QC-DFB) lasers as mid-infrared spectroscopic sources address this need. A numbe...

Related Articles Design and modeling of InP-based InGaAs/GaAsSb type-II “W” type quantum wells for mid-Infrared laser applications J. Appl. Phys. 113, 043112 (2013) Analysis of perturbations in the lateral far-field of blue InGaN laser diodes Appl. Phys. Lett. 102, 043504 (2013) In-depth analysis of injection-seeded long external cavity InGaN/GaN surface-emitting laser J. Appl. Phys. 113, 04310...

Related Articles Mid-infrared-pumped, electrically driven terahertz quantum laser: Enhanced pumping efficiency and prevention of electric-field domains J. Appl. Phys. 113, 033103 (2013) How does external feedback cause AlGaAs-based diode lasers to degrade? Appl. Phys. Lett. 102, 023502 (2013) Large-area ultraviolet GaN-based photonic quasicrystal laser with high-efficiency green color emission ...

We report the design, fabrication and experimental characterization of surface-emitting terahertz (THz) frequency quantum cascade lasers (QCLs) with distributed feedback concentric-circular-gratings. Single-mode operation is achieved at 3.73 THz with a side-mode suppression ratio as high as ~30 dB. The device emits ~5 times the power of a ridge laser of similar dimensions, with little degradati...