At present the ultrashort light pulses' (USP) shape and duration is measured by streak cameras with time resolution of the order of 1.10-" s /1/. Besides, USP measurement is frequently performed by nonlinear frequency converters (intensity correlators) (see, for instance, /2/) which utilize the second harmonic generation and provide information only on the pulse duration; this should be viewed as a shortcoming of such correlators. Although the intensity autocorrelation function G(2)(t) detected by this type of correlators and accompanied by the calculation of the phase of the pulse intensity Fourier spectrum makes it possible to recover in principle the USP shape as well /3/, such recovery is ambiguous since for both the direct and the time-reversed pulses the function G (2) (t) is the same. At the same time, it has been demonstrated in /4/ that the USP shape can be determined if one measures the third order intensity correlation function (ICF) G3 (t1 , t2 ). The authors of /5/ obtained this quantity by using three-photon fluorescence. The present contribution suggests a method for ICF measurement which is based on the cascade third harmonic generation of the initial pulse frequency. The advantages of the procedure in question with respect to the method of three-photon fluorescence resemble those of the conventional second harmonic generation as compared with two-photon fluorescence.

Date Published: 1 February 1985
PDF: 3 pages
Proc. SPIE 0491, 16th Intl Congress on High Speed Photography and Photonics, (1 February 1985); doi: 10.1117/12.967915

Published in SPIE Proceedings Vol. 0491:
16th Intl Congress on High Speed Photography and Photonics
Michel L. Andre; Manfred Hugenschmidt, Editor(s)