Fig. 3: Infrared supercontinuum from cascaded IPDFG.
Blue curves show the measured (solid) and simulated (dashed) spectra of the p-polarized IPDFG stage output for a relative phase of Δφ = 0 (constructive interference). The orange curves show the same settings as the blue curves, but for a relative phase of Δφ = π (destructive interference). The light-red-shaded area shows the overlap region where interference effects occur (Fig. 1). The inset shows the spatial beam profile of the mid-IR continuum (λ > 3.6 µm, Δφ = 0). The sharp features showing up near 100 and 270 THz in the simulations (both Δφ = 0 and Δφ = π) are probably artefacts arising from numerical approximations. The spectral resolution of 50 nm—chosen for higher signal-to-noise ratios—was insufficient to verify their presence.
