Applications of fs lasers to nonlinear spectroscopy and process control of Si

Si(O0 1) interfaces are among the most technologically important for nonlinear optical analysis, yet their exceptionally weak interfacial second harmonic susceptibility )I12)hsa s strongly inhibited quantitative interface-specific second harmonic (SH) spectroscopy and related nonlinear optical process control applications. The advent of widely tunable. unamplified femtosecond (fs) solid-state lasers has overcome this banier by enabling unprecedented SH generation efficiency (- lo6 photons/s) with minimal interface heating.