Experimental demonstration of internal wavelength conversion in the magnesium atomic filter

Abstract

We describe what is to our knowledge the first experimental demonstration of internal wavelength conversion in the metastable Mg atomic filter. The filter operates at a Fraunhofer line, thereby offering intrinsic solar background rejection. Incoming green Fraunhofer photons (518 nm) are absorbed by metastable Mg atoms in an oven cell and are converted into UV (384-nm) photons. We observed a green-to-UV conversion efficiency of greater than 50%.