Under the action of the fundamental wave of a laser with λ = 1.06/μm, the biological monoJayers of HPD and riboflavin molecules adsorbed on an optical surface can generate SH and TH signals. The beam divergence angle of SH and TH of the HPD layer is 1 mrad, equal to that of the fundamental wave. It is, however, different from that of the ribaflavin layer. The harmonic light beams diffuse into a wide angle.