Continuous wave operation of buried heterostructure 4.6 µm quantum cascade laser Y-junctions and tree arrays.

Room-temperature continuous-wave operation for buried heterostructure 4.6 µm quantum cascade laser Y-junctions and tree arrays, overgrown using hydride vapor phase epitaxy, has been demonstrated. Pulsed wall plug efficiency for the Y-junctions with bending radius of 5mm was measured to be very similar to that of single-emitter lasers from the same material, indicating low coupling losses.

Multiwatt long wavelength quantum cascade lasers based on high strain composition with 70% injection efficiency.

A strain-balanced, AlInAs/InGaAs/InP quantum cascade laser structure, designed for light emission near 9 µm, was grown by molecular beam epitaxy. Laser devices were processed in buried heterostructure geometry. Maximum pulsed and continuous wave room temperature optical power of 4.

Tapered 4.7 μm quantum cascade lasers with highly strained active region composition delivering over 4.5 watts of continuous wave optical power.

A strain-balanced, Al0.7In0.22As/In0.

λ~7.1 μm quantum cascade lasers with 19% wall-plug efficiency at room temperature.

Strain-balanced In0.6Ga0.4As/Al0.

Activation energy study of electron transport in high performance short wavelengths quantum cascade lasers.

We present a method to study current paths through quantum cascade lasers (QCLs). The temperature dependence of the current is measured at a fixed voltage. At low temperatures we find activation energies that correspond to the energy difference between the injector ground state and the upper laser level.

Optically multiplexed multi-gas detection using quantum cascade laser photoacoustic spectroscopy.

We report high-throughput, nondispersive optical multiplexing of laser beams using a scanning galvanometer. We have utilized this technique for multispecies trace-gas detection using multiple quantum cascade laser photoacoustic spectroscopy. We demonstrate switching from one laser to another in less than 1 s, a performance level needed for a comprehensive multispecies sensor, and a high signal-to-noise ratio detection of five gaseous components, NH(3), NO(2), dimethyl methyl phosphonate (DMMP, a simulant for nerve agents), acetone, and ethylene glycol, in a room air gas mixture containing approximately 3 ppb of NH(3), approximately 8 ppb of NO(2), approximately 20 ppb of DMMP, approximately 30 ppb of acetone, and approximately 40 ppb of ethylene glycol.

Sub-parts-per-billion level detection of dimethyl methyl phosphonate (DMMP) by quantum cascade laser photoacoustic spectroscopy.

The need for the detection of chemical warfare agents (CWAs) is no longer confined to battlefield environments because of at least one confirmed terrorist attack, the Tokyo Subway [Emerg. Infect. Dis.

High-sensitivity detection of TNT.

We report high-sensitivity detection of 2,4,6-trinitrotoluene (TNT) by using laser photoacoustic spectroscopy where the laser radiation is obtained from a continuous-wave room temperature high-power quantum cascade laser in an external grating cavity geometry. The external grating cavity quantum cascade laser is continuously tunable over approximately 400 nm around 7.3 microm and produces a maximum continuous-wave power of approximately 200 mW.

Sub-parts-per-billion level detection of NO2 using room-temperature quantum cascade lasers.

We report the sub-parts-per-billion-level detection of NO2 using tunable laser-based photoacoustic spectroscopy where the laser radiation is obtained from a room-temperature continuous-wave high-power quantum cascade laser operating in an external grating cavity configuration. The continuously tunable external grating cavity quantum cascade laser produces maximum single-frequency output of approximately 300 mW tunable over approximately 350 nm centered at 6.25 microm.

Improved performance of quantum cascade lasers through a scalable, manufacturable epitaxial-side-down mounting process.

We report substantially improved performance of high-power quantum cascade lasers (QCLs) by using epitaxial-side-down mounting that provides superior heat dissipation properties. We used aluminum nitride as the heatsink material and gold-tin eutectic solder. We have obtained continuous wave power output of 450 mW at 20 degrees C from mid-IR QCLs.