A femtosecond waveform transfer technique using type II second harmonic generation

We present a novel waveform frequency conversion technique by type II second harmonic generation (SHG). We have theoretically studied and experimentally demonstrated femtosecond waveform transfer from 800 to 400 nm wavelength by type II SHG in a lithium triborate (LBO) crystal. The output second harmonic (SH) waveform is a temporally magnified or compressed version of the input fundamental waveform, depending on the experimental configuration. Our experiments demonstrate that this technique can transfer not only the intensity profiles of the fundamental waveform, but also the phase profiles. This technique shows promise for programmable generation of shaped ultrafast optical waveforms down to the UV range, where direct pulse shaping is challenging.