All-laser-microprocessed waveguide Cr:ZnS laser

We report the proof-of-concept of an operational laser active medium with a depressed cladding waveguide manufactured in the volume of a Cr²⁺:ZnS single-crystalline sample and antireflection microstructures fabricated on its facets exclusively by femtosecond laser processing techniques. This allowed us to achieve transmittance in a broad range from 2 to 8 µm, approaching a maximum of over 90% near 2.5 µm, and lasing at 2275 nm at the average output power of 20 mW for the absorbed pump power of 500 mW with the slope efficiency of 5.5 %. This demonstration opens up a route towards the industrial fabrication of compact integrable laser sources and sensors based on II-VI materials.