Temporal and spectral characterizations of tunable noncollinear optical parametric amplifier

We experimentally investigate the temporal and spectral information from a broadband tunable femtosecond noncollinear optical parametric amplifier (NOPA), and present the spectral characterizations through the time–bandwidth products (τΔv). The time–bandwidth products of the signal are from 0.26 to 0.36, which are very similar to that of the pump (about 0.34) due to the time-correlated radiation. However, the time–bandwidth products of the idler are from 0.13 to 0.63, which present a larger variable range due to the more spatial freedom. We also experimentally demonstrate that the spectral bandwidth of the output signal is gradually widened when it is tuned to the longer central wavelength, which is approximatively following a λ2 scaling law.