Applications notably include HHG of short EUV and soft-x-ray pulses.

A n apparatus that includes two optical parametric chirped pulse amplification stages has been built as a means of generating few-cycle, common-envelope (CE)-phase-stable, high-energy optical pulses. [CE phase is the phase of an optical carrier-signal waveform relative to the pulse envelope waveform. CE phase is an important property of fewcycle pulses, and CE-phase stability is essential in typical applications involving few-cycle pulses.] The apparatus can generate two-cycle (14-fs-duration) pulses at a nominal middle wavelength of 2 μm, and two-cycle (5-fs-duration) pulses at a nominal middle wavelength of 800 nm at a repetition rate of 1 kHz, without need for pulse compression by an external apparatus. The apparatus is intended for use in high-harmonic generation (HHG) of extreme ultraviolet (EUV) and soft x-rays in the near term, extending to production of attosecond EUV and soft-x-ray pulses in the longer term. Moreover, this apparatus is expected to enable exploration of generation of fewand single-cycle laser pulses over the wavelength range from 700 to 2.6 μm.

Two OPA Stages are combined with pulse-stretching, pulse-compressing, pulse-synchronizing, and ancillary optical amplification stages to generate two-cycle optical pulses.