SIMULTANEOUS MEASUREMENT OF AMPLITUDE AND PHASE IN SURFACE 2ND-HARMONIC GENERATION

The intensity and the phase in surface second-harmonic generation were simultaneously measured by use of an ac optical balanced homodyne det ection system. in this system the surface second-harmonic wave was sup erimposed upon a local oscillator wave generated by a barium berate no nlinear optical crystal and then detected as an interference signal. E xtremely high sensitivity of 3 aW (6 photons/s) and high precision wer e achieved by use of a lock-in amplifier, in which an interference sig nal of fundamental waves was used as a reference signal. Simultaneous measurement of the intensity and the phase in surface second-harmonic waves generated From native-oxidized Si(111) surfaces is demonstrated. (C) 1998 Optical Society of America.