A Modulator for Generating High-Energy Terahertz Rate Pulse Trains

Direct sources of ultrashort femtosecond laser pulses become very expensive when they are amplified to J-level energies. However, such energies are readily available at relatively low cost from lasers providing narrowband nanosecond pulses like Nd:YAG-based systems. For applications demanding high frequency bursts rather than single pulses, such as laser material processing, the bandwidth required for femtosecond pulse durations can be achieved by electro-optic phase modulation [1], [2]. Conventional traveling-wave modulators, however, are constrained to radio-frequency modulation fields and thus limited in the burst frequency to around 100 GHz.