Enhancing the yield in surface sum-frequency generation by the use of surface polaritons

Abstract

Summary form only given. Sum-frequency (SF) generation has developed into a convenient tool to investigate molecular layers at interfaces. One commonly associates this nonlinear optical technique with the use of tunable high-power laser sources. Given the finite power of the available sources much can be gained by optimally coupling the incident fields to the molecular layer and/or increasing its effective thickness. Surface polaritons provide a mechanism to achieve both these goals as we have demonstrated in a series of experiments on infrared-visible SFG at the air-silver interface. Two to four orders of magnitude increase in the SF yield have been observed when one of the input beams was coupled into a surface polariton.