Diode-pumped Cr:ZnS laser oscillators have been developed at attoworld as new sources for controllable single-cycle infrared pulses with exceptional intensity and phase stability (Controlling the waveform of ultrashort infrared pulses). However, the average output power of such laser oscillators is typically limited to below 1 W. Dr. Shizhen Qu and co-workers from the cmf laser science team have now shown, how to scale the power further to the multi-Watt level, while maintaining the ultra-low noise behavior of the oscillator. In a demonstration experiment they post-amplified the output of an ultrafast Cr:ZnS oscillator in a single Cr:ZnS crystal. By combining four single-emitter diodes as low-noise pump sources for the amplification, they were able to boost the oscillator output to 2.2 W, with minimum added intensity noise. The approach is scalable towards higher powers by increasing the optical output power of the pump diodes or combining more diodes into a single pump beam. The resulting multi-Watt Cr:ZnS lasers with ultra-low intensity noise are the ideal sources for generating bright, multi-octave-spanning mid-infrared pulses for spectroscopic applications. Our newest generation of field-resolved infrared fingerprinting instruments will integrate this technology to improve the sensitivity of blood-based infrared health monitoring and disease detection. Meanwhile, Dr. Shizhen Qu has moved on in his career to work for the Huawei company. The cmf laser science team around Dr. Alexander Weigel will continue to pursue this technology towards high-average-power, low-noise Cr:ZnS lasers.

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