Generation and control of phase-locked conical wave packets in type-I seeded optical parametric amplification

We demonstrate a technique for broadband conical pulse generation based on a continuum seeded parametric amplification process in quadratic nonlinear media. We show that by using an appropriately focused broadband weak seed we are able to selectively generate and amplify a single phase-locked conical wave packet. We present experimental spatiotemporal spectra obtained with two different crystals in type I phase-matching configurations, showing the generation and amplification of single X-type and O-type wave packets, respectively, and we compare the results with the stationary wave modes that can be supported in the parametric amplification process. On the basis of numerical calculations, we also show that the broadband signal+idler phase-matched field generated by the amplifier may be characterized by a well-defined phase velocity, whose control is guaranteed by the tunability of the amplifier spectral gain curves.