Quantum analysis of the z-scan technique

A Gaussian-wave theory is developed for the classical and quantum analysis of the z-scan method that is often used to measure third-order nonlinearities. The theory allows us to compute the transmittance in the z scan and the associated regimes of amplitude squeezing. The classical limits of our theory are in perfect agreement with the previous theoretical results. We show that amplitude squeezing of 1.2 dB can be obtained using the z scan with a careful selection of the signal power and the aperture size. (c) 2006 Optical Society of America.