freshphotons:

“Broadband light generation in Raman crystals. We focused two femtosecond laser beams into a 500-µm-thick PbWO4 Raman crystal to generate a broad spectrum of coherent Raman sidebands. The orange line is the 870-nm Stokes beam and the purple is the 800 nm pump beam; the rest are sideband beams. We observed 23 anti-Stokes and 2 Stokes Raman sidebands. -Miaochan Zhi, Kai Wang and Alexei V. Sokolov” Via.