Here’s the layout of the non-colinear optical parametric amplifier (NOPA). It’s a tunable light source which can produce laser light anywhere across the visible spectrum. It’s fed by the output of our titanium-sapphire regenerative amplifier (Spitfire, Spectra Physics), which provides 100 fs duration pulses with a 1 kHz repetition rate, centred at a wavelength of 800 nm. We split that to produce a white-light continuum seed and a 400 nm pump beam. The precise angle and timing of the overlap of these beams on the nonlinear crystal (beta barium borate, BBO) will change the wavelength of the NOPA output. Currently this is generating light centred around 600 nm.
The output is strongly affected by the quality of the white-light seed. The white light is produced by focusing a small amount of the 800 nm laser onto a pure sapphire crystal. The produced white light radiates out and needs to be collected and collimated using a precisely placed curved mirror.