Tunable Laser Absorption Spectroscopy (TLAS) has proven to be a versatile tool for gas sensing applications with
significant advantages compared to other techniques. These advantages include real time measurement, standoff
detection and ruggedness of the sensor. Especially the Mid-Infrared (MIR) wavelength region from 3 to 6 microns is of
great interest for industrial process control and the reduction of pollutants. In this contribution we present novel ICL
devices developed to address the crucial air pollutant sulfur dioxide SO2 at its transition around 4 μm. In general,
interband cascade lasers (ICLs) have evolved into important laser sources for the MIR spectral range. Compared to
quantum cascade lasers, they offer significant advantages with respect to threshold power density as well as overall
power consumption. In contrast to conventional diode lasers, ICLs are able to cover the entire MIR wavelength range of
For application in TLAS, single-mode devices are required. In this work application-grade distributed feedback (DFB)
ICL devices for addressing SO2 at the wavelength range around 4 μm are presented. A lateral metal grating, defined by
electron beam lithography, is used to achieve DFB operation and hence spectrally single-mode emission. Continuous
wave laser operation with threshold power consumption below 100 mW at room temperature, side mode suppression
ratio of > 30 dB and wavelength tuning range up to 28 nm are demonstrated.
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J. Koeth ; M. von Edlinger ; J. Scheuermann ; S. Becker ; L. Nähle, et al.
Interband cascade laser sources in the mid-infrared for green photonics
", Proc. SPIE 9767, Novel In-Plane Semiconductor Lasers XV, 976712 (March 10, 2016); doi:10.1117/12.2212644; http://dx.doi.org/10.1117/12.2212644