Battery?Operated Mid?Infrared Diode Laser Frequency Combs

Mid-wave infrared (MIR, 3–5 µm) optical frequency combs (OFC) are of critical importance for spectroscopy fundamental molecular transitions in space and terrestrial applications. Although this band OFCs can be obtained via supercontinuum or difference generation using pumping schemes, unprecedented source miniaturization, monolithic design unique to electrically-pumped semiconductor laser structures. To date, high-brightness OFC region has been demonstrated quantum- interband cascade lasers (QCL/ICL), yet with sub-optimal spectral properties. Here, an MIR quantum well diode (QWDL) is shown, whose excellent uniformity, narrow linewidths, milliwatt power at a fraction watt consumption. The continuously tunable offers ?1 THz span centered 3.04 µm, repetition rate 10 GHz. As proof-of-principle, directly-battery-operated dual-comb shown almost 0.5 coverage accessible the electrical domain microseconds. These results indicate high suitability QWDL future chip-based real-time sensing systems mid-infrared.