Third-order correlator for measuring the time profile of petawatt laser pulses

A third-order correlator with a single-shot time window and a full dynamic range of 10⁸ is developed. The time contrast of radiation from the front-end system of a petawatt femtosecond laser complex measured with the correlator within time windows ±1 ps and ±100 ps was 10⁴ and more than 10⁸, respectively. Based on the theoretical analysis of the cross-correlator operation, a number of requirements providing the optimal functioning of the cross-correlator are found. The reasons restricting the technical parameters of the correlator are discussed.