Random lasing in Cr:ZnS microstructure-textured grooves

We report a random lasing emission based on microstructure-textured grooves of Cr:ZnS crystal. The microstructures include horizontal ripples and a vertical periodic structure with dozens of micrometers of periods, which are induced by the Fresnel diffraction of femtosecond laser in the grooves and the interference of laser light through the micropores, respectively. The microstructures multiple-scatter the light, resulting in lasing emission with a center wavelength of 2250 nm and a relatively low lasing threshold of similar to 80 mu J/pulse. There is a dramatic shortening of the emission lifetime as the pump energy increases. The emission peaks are shifted by pumping at the microstructures with different vertical periods. It shows a structural stable property for potential random laser applications.