This paper gives an overview on the design, fabrication, and characterization of quantum cascade detectors. They are tailorable infrared photodetectors based on intersubband transitions in semiconductor quantum wells that do not require an external bias voltage due to their asymmetric conduction band profile. They thus profit from favorable noise b...
Many applications exist for high performance lasers in the short-wave, mid-infrared spectral regime between 1.9 and 2.5µm - from long-range communications systems through to remote atmospheric gas sensing and pollution monitoring. However, a simple, efficient laser source offering the desired performance characteristics and flexibility has not been...
A midinfrared quantum cascade detector with a spectrally broad (deltaE/E=27.3%) response is designed, fabricated, and tested. This detector consists of 26 differently designed active region stages in order to cover a wavelength region from 4.7 to 7.4 µm. The device could be operated above room temperature and showed peak responsivities of 13 mA/W a...
We report the measurements of dispersive gain (simultaneous coexistence of gain and losses on a single intersubband transition) in a quantum cascade laser. Broadband transmission spectra through the waveguide of a Lambda ~4.7 µm In0.53Ga0.47As/AlAs0.56Sb0.44/InP quantum cascade laser have been studied at a bias below laser threshold and at differen...
We report on the experimental study of the electronic and thermal properties in state of art Sb-based quantum-cascade lasers (QCLs) operating in the range 4.3-4.9 µm. This information has been obtained by investigating the band-to-band photoluminescence signals, detected by means of an InGaAs-array detector. This technique allowed to probe the spat...
Based on type-II InAs/GaSb superlattice photodiodes, the first report of a dual-colour infrared camera with excellent NETD values
Focal Plane Arrays for high-performance thermal imaging systems operating in the mid-infrared spectral range between 3-5 µm have been realized by type-II InAs/GaSb short-period superlattices. A fully operational 256 x 256 camera system showing a noise equivalent temperature difference below 10 mK is presented. The suitability of InAs/GaSb type-II s...
High-power high-brightness 1.93-µm wavelength (AlGaIn)(AsSb) tapered diode lasers with a narrow vertical waveguide design are reported for the first time. A nearly diffraction-limited continuous-wave output power of 1.5 W together with a remarkable low fast axis divergence of 43° full-width at half-maximum have been demonstrated. The maximum bright...
We report on the demonstration of continuous-wave (CW) operation of GaInAs-AlGaAsSb quantum cascade (QC) lasers. By placing a 2.5-µm-thick gold layer on both sides of the laser ridge to extract heat from the active region in the lateral direction, together with mounting the device epilayer down, we have achieved CW operation of GalnAs-AlGaAsSb QC l...
We report on molecular beam epitaxial growth and characterization of InAs/GaInSb/InAs/AlGaAsSb type-II miniband-to-bound state W-lasers. Laser core structures were characterized using photoluminescence, high resolution X-ray diffraction and Raman spectroscopy to reveal the best growth conditions. The growth temperature for the laser core was varied...
