Efficient vapor-phase vacuum ultraviolet (VUV) frequency conversion

Summary form only given. The techniques of electromagnetically induced transparency (EIT) may be employed in order to create an effective nonlinear response at a given wavelength which is equal in magnitude to the linear response at that wavelength. Physically, this allows frequency converters wherein 100% photon-to-photon conversion occurs in a single coherence length, i.e., in that distance which causes a /spl pi/ phase slip between the driving polarization and the generated electromagnetic wave. These ideas were first implemented by Jain et al. (1996), to convert 425 nm to 293 nm, in a medium consisting of a single isotope of Pb. This paper reports the demonstration of a vapor-phase VUV frequency converter from 233 nm to 186 nm with an energy conversion efficiency exceeding 35%; the maximum generated signal energy and power were 250 /spl mu/J and 25 kW. The net conversion efficiency to 186 nm, including all beams, is roughly 2%. These wavelengths were chosen to demonstrate the utility of this type of frequency converter to generate wavelengths outside the transparency window of most crystalline media. Our technique involves the application of two strong laser fields which are almost two-photon resonant with a Raman transition of the Pb atoms.