Fig. 5: Characterization of the generated femtosecond HG modes.

a Spectra and autocorrelation traces for HG10,0 to HG20,0 femtosecond pulses generated with the hybrid angle-based non-collinear pumping approach. b Spectra and autocorrelation traces for HG21,0 to HG30,0 femtosecond pulses. c Pulse trains of femtosecond HG30,0 pulses on different time scales. d RF spectrum of femtosecond HG30,0 pulses, showing a high signal-to-noise ratio of ~75 dB with a resolution bandwidth (RBW) of 100 Hz