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Quantum Cascade Lasers (QCLs) are considered as one of the most versatile sources of light in the mid-IR spectral range. The need for mid-IR lasers not only emitting at precisely selected wavelengths but showing also a high spectral purity is now growing, driven by numerous possible applications such as high-resolution spectroscopy in the molecular fingerprint region, e.g. in combination with optical...
Since the first demonstration of distributed feedback quantum (DFB) quantum cascade (QC) lasers in 1997 [1] tremendous progress has been made in the development of single-mode emitting QC lasers [2-4]. Such kind of devices are of particular interest because a lot of different molecules, like CO2, N2O or CH4, have their fundamental modes in the mid-infrared spectral region (3–12 μm).
Frequency noise and linewidth properties of different mid-infrared DFB-QCLs using buried-heterostructures and ridge waveguides are compared. The physical origin of frequency noise and the impact of the different lasers parameters are discussed.
The quantum cascade laser (QCL)[1] has demonstrated operation over an extremely wide wavelength range extending from the mid-infrared at 2.9μm to the Terahertz at 360μm. In addition, quantum cascade lasers operating in the mid-infrared have now demonstrated extremely high powers (>1W c.w.) with increasingly high wallplug efficiencies (>25%)[2, 3]. As shown in Fig. 1, in a new development, ultra...
Presented are narrow-ridge, singlemode (λ = 4.49 mm) quantum cascade lasers with low power consumption in continuous-wave operation. Episide up mounted 3 μm-wide and 1 mm-long devices with high-reflectivity backside coating show an electrical dissipation at laser threshold as low as 840 mW at 20°C. The devices can be tuned singlemode and mode-hop free between -30°C and +50°C and in a range of injected...
DFB QC lasers are presented showing very low electrical dissipation of 804 mW and a maximum optical output-power of >8.5 mW at 20°C in continuous-wave operation. Junction-up mounting maintains a large tuning-range of −4.66 cm−1/W.
We present the time-resolved spectral analysis of the settling process in a pulsed external-cavity quantum-cascade laser (EC-QC laser) emitting in the wavelength range around 7.4 μm. Due to mode competition between the two cavities formed by the laser-chip on one hand and the external-cavity on the other hand, a time-dependent spectral emission on a ns time-scale can be observed. Depending on the...
In this paper we report experimental results on the generation of broadband terahertz (THz) radiation using photoconductive emitters on the base of low-temperature-grown (LT) InGaAs for excitation with 1060 nm wavelength. The material properties of the semiconductor layers were investigated and the emitter function optimised. As experimental arrangement we have used a THz time-domain-spectroscopy...
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