Shaping octave-spanning ultrashort laser pulses using multiple prisms

Abstract

A comprehensive study on the generation, manipulation, and temporal characterization of octave-spanning ultrashort laser pulses is presented. We achieve this by introducing high-energy laser pulses from a Ti:sapphire laser system into a neon-filled, differentially-pumped hollow-core fiber. This results in the generation of intense octave-spanning ultrashort laser pulses. By measuring the spectrum of the generated pulses, we confirm the occurrence of spectral broadening within the hollow waveguide. The transform-limited pulse duration of the spectrum demonstrates the potential to produce few-cycle pulses. The temporal characterization of octave-spanning ultrashort laser pulses using the measurement technique called tunneling ionization with a perturbation for the time-domain observation of an electric field (TIPTOE) is performed. By applying the reconstruction algorithm based on adaptive moment (Adam) method to the ionization yield of the few-cycle pulse, its temporal profile is suscessfully reproduced. The reconstructed spectrum shows good consistency with the spectrum measured using a grating-based spectrometer, supporting the validity of the measurement. We also perform temporal characterization of a two-color laser pulse using the tunneling ionization technique. By utilizing multiple ionization yield measurements near the laser focus, we can completely determine the temporal profiles of the fundamental laser pulse and its second harmonic pulse, as well as their relative phase. The accuracy of the characterization is confirmed by comparing the spectra of the reconstructed pulses with those measured using a grating-based spectrometer, which shows good agreement. Finally, we present a novel prism-based pulse shaper that enables the tailoring of various waveforms of broadband laser pulses. By splitting the incident beam into separate beams using multiple prisms and controlling the amplitude and phase of each beam independently, we demonstrate the generation of near-single-cycle and double pulses. The multiple-prism configuration of the pulse shaper also allows for compensation of a huge amount of optical dispersion over an octave-spanning spectrum, enabling precise pulse shaping over a broad spectral range without the need for additional compressors or chirped mirrors.