LETTERS TO THE EDITOR: Efficient four-wave mixing near vibrational resonances in ozone
Generation of the sum frequency 2ν1 + ν2 by vibrational–rotational transitions of molecules in the gaseous phase was achieved for the first time. The pump sources were a CO2 laser and the nonlinear medium was ozone. A high conversion efficiency, of the order of 0.1% on the energy scale, was attained.