Generation of programmable GHz burst-mode ultrashort pulses using free-space angular-chirp-enhanced delay

In this work, we propose a method for generating programmable GHz burst-mode ultrashort pulses from existing pulse sources with kHz-MHz fundamental repetition rates. It enables flexibly controlling the pulse number and intensity pattern of GHz pulse burst, as well as the repetition rate of the intra-pulses and physical time delay of the pulse. This method leverages an acousto-optic deflector (AOD) with radio-frequency encoded programmability in conjunction with a pair of long non-parallel mirrors, known as free-space angular-chirp-enhanced delay (FACED). The AOD enables real-time programming of the angular difference for aligning with the discrete angular reflection condition of FACED, facilitating the programmable splitting of a single pulse into burst-mode pulses with a GHz repetition rate. The versatility of this burst-mode GHz ultrashort pulses generation technique makes it well-suited for various applications, including material processing and nonlinear imaging.