Sampling period criterion in a scanning-beam technique.

The scanning-beam technique for measuring the response of a detector to an irradiance is analyzed. With this method the irradiance responsivity is determined by integration of the spatial responsivity. Since in practice the integration is approximated by a summation over steps with a finite step size, errors are introduced. It is shown both theoretically and experimentally that the error vanishes when the reciprocal step size lies beyond the diffraction limit. Furthermore, comparison shows that experiment and theory are in good agreement.

Self-dispersive sum-frequency generation at interfaces.

We employ the self-dispersive nature of infrared-visible sum-frequency generation at interfaces to record sumfrequency spectra of molecular monolayers with a spectral resolution of a few inverse centimeters, using IR light with a spectral content of approximately 50 cm(-1).

Transmission reflection anomaly in second-harmonic generation from a monolayer.

We show experimentally that in second-harmonic generation from a monolayer the radiation propagating in transmission and that in reflection can have very different magnitudes. The origin of this difference lies in destructive and constructive interference of the components of the nonlinear polarization that drive the field at the second-harmonic frequency.