Figure 3. f–2f interferometer for supercontinuum generation.

Schematic of the f–2f interferometer for monitoring the stability of the supercontinuum. Red and blue beams represent the fundamental and the second harmonic, and the correspondingly coloured arrows represent the polarization state. The fundamental and its orthogonally polarized second harmonic, produced in a beta-barium borate crystal, are projected onto the same polarization state by a beamsplitter cube.