Milliwatt midinfrared from intrapulse difference frequency with a single erbium fiber laser

We generate about 2 mW of midinfrared in orientation-patterned gallium phosphide pumped by an erbium fiber laser. The midinfrared spectrum has a strong component around 8 to 10 μm wavelength, with a broad background from about 7 to 12 μm. The pump laser has 5 W, single mode output at 96 MHz compressed to 65 fs, with a peak power of up to about 0.6 MW. Before midinfrared generation, we further broaden and recompress the pulses in a small length of fiber, obtaining 3 W of 17 fs pulses with peak power near 1 MW but broader bandwidth to generate midinfrared.