Noncollinearly phase-matched femtosecond optical parametric amplification with a 2000 cm−1 bandwidth

Abstract

An optical parametric amplifier generating as short as 14 fs pulses in a visible region has been constructed in a noncollinear phase-matching configuration. The group-velocity matching between the signal and idler enormously broadens the gain bandwidth up to 2000 cm−1, which is mainly limited by the chirp of the seed pulses. Pulses shorter than 20 fs are tunable from 550 to 690 nm by scanning the delay-line of the pump beam.

Control of reaction efficiency by two-color two-pulse excitation: Photoisomerization of indocyanine green in condensed phase

“…If one assume that the energy relaxation as large as NIR one-photon energy does not occur between UV onephoton process and NIR multi-photon process on the reaction path, one guess the optical order of NIR process as two considering the ionization energy of ICG (6-7 eV) [19] which is smaller than NIR five-photon energy. Time-resolved photoemission spectroscopy with frequency-tunable ultrashort pulse like NOPA [20] should be conducted to investigate such a large energy relaxation. Figure 8a shows the schematic diagram of this new reaction path.…”

Excited-state dynamics of the 1Bu+,3Ag−, and 1Bu− states in a carotenoid molecule by 5-fs absorption spectroscopy

“…In the present investigation, we utilized sub-5-fs pulses [6][7][8][9], in order to identify the 3A À g and 1B À u states, and to determine the intrinsic relaxation dynamics of spirilloxanthin (n ¼ 13).…”

“…The sub-5-fs 1 kHz pulse train was generated from the noncollinear optical parametric amplifier (NOPA) with a pulse compressor [6,7,9] and its wavelength range is from 500 to 750 nm.Energy of the pump pulse at the sample was about 40 nJ and that of the probe pulse was a quarter of the pump pulse. In order to measure weak pump-probe signals at various wavelengths, we used a multichannel lock-in amplifier with a 210 Hz chopper.…”

A short perspective on long crystals: broadband wave mixing and its application to ultrafast quantum optics

“…First, one can match not the group velocities of the interacting fields but rather their projections onto a certain axis in the noncollinear geometry-a scheme known from broadband second harmonic generation [37,38] and parametric amplification of femtosecond laser pulses [39,40].…”