Visible-spanning flat supercontinuum for astronomical applications
arXiv:1807.07857 · doi:10.1109/JLT.2018.2872423
Abstract
We demonstrate a broad, flat, visible supercontinuum spectrum that is generated by a dispersion-engineered tapered photonic crystal fiber pumped by a 1 GHz repetition rate turn-key Ti:sapphire laser outputting $\sim$ 30 fs pulses at 800 nm. At a pulse energy of 100 pJ, we obtain an output spectrum that is flat to within 3 dB over the range 490-690 nm with a blue tail extending below 450 nm. The mode-locked laser combined with the photonic crystal fiber forms a simple visible frequency comb system that is extremely well-suited to the precise calibration of astrophysical spectrographs, among other applications.
Accepted for publication by Journal of Lightwave Technology. Code and data available online at http://walsworth.physics.harvard.edu/code/scgen-taper.zip