Further investigation of noncollinear surface-wave interactions

Abstract
Two noncollinear surface waves of 5 and 7 MHz have been excited on the surface of single‐crystal copper samples in such directions that the waves could interact via the nonlinearities of the medium to produce a third surface wave at the sum frequency of 12 MHz. Using optical techniques, the three waves involved have been detected on two crystal surfaces, the (001) and (111) planes of copper, and the amplitude of each of the waves has been measured.