Stimulated Raman amplification of femtosecond pulses in hydrogen gas

Krylov, V. N.; Rebane, Alexander; Erni, Daniel; Ollikainen, O.; Wild, Urs P.; Bespalov, V. G.; Staselko, D. I.

doi:10.1364/ol.21.002005

Cited by 36 publications

(11 citation statements)

References 15 publications

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“…The pressure also affects the wavelength range in which the amplification is observed. Amplification of light has also been reported in previous research using another third-order nonlinearity, stimulated Raman scattering [26][27][28][29]. The amplification relies on the nonlinearity originating from the nuclear response of molecules.…”

Section: Excitation Of Rotational Wavepackets By the Pump Pulse And Tsupporting

confidence: 54%

Four-Wave Optical Parametric Amplification in a Raman-Active Gas

Kida

Imasaka

2015

Photonics

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Four-wave optical parametric amplification (FWOPA) in a Raman-active medium is experimentally investigated by use of an air-filled hollow fiber. A femtosecond pump pulse shorter than the period of molecular motion excites the coherent molecular motion of the Raman-active molecules during the parametric amplification of a signal pulse. The excited coherent motion modulates the frequency of the signal pulse during the parametric amplification, and shifts it to lower frequencies. The magnitude of the frequency redshift depends on the pump intensity, resulting in intensity-dependent spectral characteristics that are different from those in the FWOPA induced in a noble-gas-filled hollow fiber.

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Section: Excitation Of Rotational Wavepackets By the Pump Pulse And Tsupporting

confidence: 54%

Four-Wave Optical Parametric Amplification in a Raman-Active Gas

Kida

Imasaka

2015

Photonics

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“…However, an increase in pump energy leads to the appearance of self-focusing and the continuum generation, while the stretching of pulse duration to 2.4 ps effectively reduced these competing non-linear effects. Krylov et al 22 used the second harmonic of a Ti : sapphire laser with a pulse duration of 200 fs to excite SRS in compressed H 2 gas and observed threefold broadening (from 70 to 210 cm 1 ) of a depleted pump pulse and the spectral bandwidth of 150 cm 1 for the first Stokes component. The observed features have been associated with the self-phase modulation.…”

Section: Introductionmentioning

confidence: 98%

“…Bespalov et al 23 excited SRS in compressed H 2 gas using the second harmonic of a Ti : sapphire laser with a pulse duration of 400 fs and a spectral bandwidth of 70 cm 1 and found the broadening of a pump spectrum similar to that described above. 22 The spectral bandwidth of the first Stokes component was found to depend on the degree of focusing of the laser beam and became as wide as 200 cm 1 . In addition, the generation of an extended spectral continuum was observed.…”

Section: Introductionmentioning

confidence: 99%

Characterization of stimulated Raman scattering of hydrogen and methane gases as a light source for picosecond time-resolved Raman spectroscopy

Uesugi

Mizutani

Kruglik

et al. 2000

J. Raman Spectrosc.

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Stimulated Raman scattering (SRS) in compressed hydrogen and methane gas was characterized in terms of pulse energy, temporal width and spectral width in the range of gas pressures 10-60 atm to use it as a light source for picosecond time-resolved resonance Raman spectroscopy. SRS was pumped by the second harmonic of a Ti : sapphire oscillator-regenerative amplifier laser system with pulse energy up to 200 µJ, duration ∼2.5 ps and repetition rate 1 kHz. The output spectral region 421-657 nm was covered by the first and second Stokes SRS components on tuning of the pump wavelength in the range 375-425 nm. Energy conversion to the first Stokes SRS component was more than 10% with H 2 and more than 20% with CH 4 . The temporal width of the SRS pulse (1.1-2.1 ps) was shorter than that of the pump pulse. The spectral band shape was found to be modulated, since the SRS is generated in a transient regime. When more than 100 pulses were averaged, the temporal and spectral profiles of SRS pulses were sufficiently smooth and energy fluctuations were sufficiently small for spectroscopic applications. On the basis of the results obtained, optimized conditions as a Raman shifter were deduced. The Raman shifter served as a light source for two-color pump-probe time-resolved resonance Raman (TR 3 ) experiments and to demonstrate its capabilities, picosecond TR 3 spectra of nickel tetraphenylporphyrin in toluene solution were measured.

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“…[8,18], the beam profile and the divergence of the SRS radiation were badly dependent on the intensity of the pump beam, which may represent a limitation in beam shaping of the Raman laser output. There are reports on Stimulated Raman amplification with picosecond excitation, and it was found that it was useful to apply seeding to reduce the pumping threshold and improve the parameter of the Stokes-shifted radiation in the transient regime [16,[19][20][21]. Recently, Vodchits and co-workers have conducted experimental investigation on OPA used as an energy amplifier for amplifying multi-frequency SRS pulses generated in a gas mixture of compressed hydrogen and methane.…”

Section: Introductionmentioning

confidence: 99%