Abstract: The present invention contemplates an integrated oscillator-amplifier system for deep UV generation. The system employs a long cavity oscillator to lengthen the pulse build-up time and to control the pulse spectral bandwidth. Meanwhile the system employs a short cavity amplifier to shorten the energy extraction time to produce a single short pulse with good energy extraction efficiency. The system further integrates the oscillator and the amplifier by inserting the amplifier cavity inside the oscillator cavity via a mirror of low reflectivity. As a result, the integrated system has a long build-up time to generate a seed pulse in the long cavity oscillator and has a short energy extraction time to generate a short amplified single pulse in the short cavity. Consequently, the integrated system can accommodate a relatively long pump pulse to produce a single short amplified pulse suitable for deep UV laser generation.