We present a simple method to measure the time-evolution of the divergence of pulsed laser beams, joining the time-resolution capability of photodetectors and the space-resolved information of the knife-edge technique. We measured the time-integrated and the time-resolved divergence of a long pulsewidth, high output energy XeCl laser (λ = 308 nm), equipped with positive branch unstable resonators having either magnification factor M = 5 or M = 9. In both cases, the time-resolved beam divergence was smaller than the time-integrated one for most of the 100 ns full-width-at-half-maximum laser pulse duration. A minimum divergence of (40 × 23) μrad2at 86.5% energy content and a peak radiance of 9 × 1014W/cm2/ster were achieved a few ns before the peak of the laser pulse, for the case of M = 9. The corresponding time-integrated values were (56 × 38) μrad2and 5 × 1014W/cm2/ster, respectively.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Physical and Theoretical Chemistry
- Electrical and Electronic Engineering
Lisi, N., Di Lazzaro, P., & Flora, F. (1997). Time-resolved divergence measurement of an excimer laser beam by the knife-edge technique. Optics Communications, 136(3-4), 247 - 252. https://doi.org/10.1016/S0030-4018(96)00696-7