Generation of sub-30 fs ultraviolet pulses by Raman induced phase modulation in nitrogen

Generation of high-energy, sub-20-fs pulses in the deep ultraviolet by using spectral broadening during filamentation in argon

Generation of sub-20-fs UV pulses with more than 300 μJ energy at 268 nm is reported. First, the UV pulses are produced by successive second-harmonic and third-harmonic (TH) generation of 805 nm pulses of a 1 kHz Ti:sapphire laser amplifier. The spectral broadening of TH pulses is realized in a filament, generated in argon. The produced pulses are compressed in a simple double-pass prism-pair compressor. Starting from 100 fs pulses, we achieve a fivefold pulse shortening.

Generation of high-energy sub-20 fs pulses tunable in the 250-310 nm region by frequency doubling of a high-power noncollinear optical parametric amplifier

We report on the generation of powerful sub-20 fs deep UV pulses with 10 microJ level energy and broadly tunable in the 250-310 nm range. These pulses are produced by frequency doubling a high-power noncollinear optical parametric amplifier and compressed by a pair of MgF2 prisms to an almost transform-limited duration. Our results provide a power scaling by an order of magnitude with respect to previous works.

Generation of intense 11-fs ultraviolet pulses using phase modulation by two types of coherent molecular motions

The use of two types of phase modulations arising from the coherent rotations of ortho-hydrogen and para-hydrogen to generate an intense ultrashort ultraviolet pulse without substantial generation of sub-pulses was demonstrated. This technique allows use of a high-energy long-probe pulse in the pump-probe regime for generating a high-energy compressed pulse. A 100-fs ultraviolet pulse was compressed to 11-fs by the phase modulation followed by dispersion compensation with chirped mirrors.

Interferometric characterization of ultrashort deep ultraviolet pulses using a multiphoton ionization mass spectrometer

The temporal characterization of a femtosecond laser pulse in the deep ultraviolet region using an interferometric autocorrelation scheme is demonstrated. Two-photon ionization of a molecule in a time-of-flight mass spectrometer was used as a nonlinear detector to obtain an autocorrelation trace. This setup proved useful in not only providing a temporal characterization of a pulse but also investigating the ultrafast dynamics of photochemical processes.