Method of ultrafast beam rotation for single-shot, time-resolved measurements

Ultrafast optical beam rotation is proposed for single-shot, time-resolved measurements. A pump–probe configuration is considered using a diffraction grating and focusing optics to create angular encoding of the time delay between the pump and probe pulses. The characteristic time tap of the grating-lens system is derived as a function of dispersion, NA, and time window T. An analytical equation for time resolution is obtained that incorporates tap, laser pulse width, and beam crossing, enabling optimum selection of optical components. For commercial standard gratings with width W≤50  mm, laser λ=800  nm, and NA=.05, a 160 ps time window can be achieved, and tap=23  fs for T=1  ps.