Noncollinear Optical Parametric Amplifier Research Articles

Femtosecond Noncollinear Optical Parametric Amplification in the Mid-Infrared Range with 1.25 µm Pumping

We study noncollinear three-wave interaction in a traveling wave optical parametric amplifier operating in the mid-infrared spectral range between 6 and 8 µm using HgGa2S4 and AgGaS2 as nonlinear optical crystals. Calculations reveal that matching of the group velocities in both crystals is possible in a wider spectral (or angular) region for type-I interaction. High-power femtosecond pulses at 1.25 µm from a Cr:forsterite regenerative amplifier are used for pumping the optical parametric amplifier at a repetition rate of 1 kHz. Experimentally we verify the advantages of noncollinear interaction by increasing the conversion efficiency approximately sixfold in the saturation regime as compared to the collinear case. The maximum idler energy measured near 6 µm exceeds 4 µJ and typical pulse durations are about 300 fs.

Sub-5-fs transform-limited visible pulse source and its application to real-time spectroscopy

Transform-limited (TL) visible pulses with as short a duration as 4.7 fs with a 5-/spl mu/J pulse energy have been generated for the first time from a novel noncollinear optical parametric amplifier. Both signal-idler group-velocity matching and pulse-front matching are essential to generate coherent down-converted pulses compressible to the TL pulse with more than 150 THz bandwidth. Tunable operation with bandwidth-limited sub-10-fs pulses in the visible (550-700 nm) and near-infrared (900-1300 nm) ranges, achieved by increasing the seed chirp, is also a marked property. Applications for ultrafast spectroscopy of the sub-5-fs pulse source to the real-time spectroscopy of conjugated polymer, a dye molecule, and J-aggregates are also described.

Femtosecond ultraviolet pulses generated using noncollinear optical parametric amplification and sum frequency mixing

We demonstrate the generation of ultraviolet 33-fs pulses with a shot-to-shot energy fluctuation of less than 3% using sum frequency mixing of visible pulses of a noncollinear optical parametric amplifier with sub-40-fs pulses of a 1-kHz Ti:sapphire-amplified system. The pulses are transform-limited (ΔνΔτ=0.36) and tunable in the range from 315 nm to 355 nm with energy above 1 μJ (2.6 μJ at 330 nm).

Tunable visible and near-infrared pulse generator in a 5 fs regime

Transform-limited (TL) visible pulses with as short a duration as 4.7 fs with a 5 μJ pulse energy have been generated for the first time from a novel noncollinear optical parametric amplifier (NOPA). Both signal–idler group-velocity matching and pulse-front matching are essential to generate coherent down-converted pulses compressible to the TL pulse with more than a 150-THz bandwidth. Tunable operation with bandwidth-limited sub-10-fs pulses in the visible (550–700 nm) and near-infrared (900–1300 nm) ranges, achieved by increasing the seed chirp, is also a remarkable property. The NOPA is believed to be on useful light source for ultrafast spectroscopy on an extremely short time-scale.

Sub-10-fs tunable pulses in visible and NIR and visible sub-5-fs pulses generated by noncollinear OPA

Transform-limited (TL) sub-10-fs pulse was successfully generated with wide tuning ranges in both the visible and near-infrared by introducing a pulse-front-matched (PFM) geometry and spatial dispersion correction to non-collinear optical parametric amplification (NOPA). This is the first report of tunable sub-10-fs pulse generation. A full-bandwidth PFM-NOPA generated the shortest visible pulses 4.7-fs.

Sub-5-fs visible pulse generation by pulse-front-matched noncollinear optical parametric amplification

Sub-5-fs pulses are generated in the visible region. A pulse-front-matched noncollinear optical parametric amplifier is operated with the full bandwidth by precompression of the seeded continuum with a customized ultrabroadband chirped mirror (UBCM) pair. The signal is compressed down to a nearly transform-limited 4.7±0.1 fs duration by a prism pair and another UBCM pair with a 5-μJ pulse energy.

Pulse-front-matched optical parametric amplification for sub-10-fs pulse generation tunable in the visible and near infrared

A noncollinear optical parametric amplifier is presented that generates transform-limited sub-10-fs pulses that are tunable in both the visible and the near infrared (NIR). The pulse-front-matched pump geometry realizes tilt-free signal amplification, and pulses as short as 6.1 fs can be obtained from 550 to 700 nm. The large angular dispersion of the idler specific to the group-velocity-matching interaction is effectively eliminated by a grating-telescope compensator, and 9-fs NIR pulses are also successfully obtained from 900 to 1300 nm. This is believed to be the first tunable sub-10-fs light source.

Sub-8-fs pulses from an ultrabroadband optical parametric amplifier in the visible

Pulses with 180-THz bandwidth and 2-microJ energy were generated by a noncollinear optical parametric amplifier in the visible, pumped by the second harmonic of a Ti:sapphire laser. A portion of the amplified pulse spectrum was compressed to 7.2 fs by use of a thin prism sequence.

Generation of 11 fs pulses tunable across the visible by optical parametric amplification

We have generated pulses with 11 fs duration, tunable between 500 and 700 nm, using a noncollinear β-barium borate optical parametric amplifier pumped by the second harmonic of a Ti:sapphire laser.