Generation of ultrashort optical pulses using multiple coherent anti-Stokes Raman scattering in a crystal at room temperature

Abstract

We demonstrate Fourier synthesis of multiple coherent anti-Stokes Raman scattering signals in a LiNbO 3 crystal at room temperature. The signals up to the 20th order ͑470-800 nm͒ were generated by two crossing femtosecond Ti:sapphire laser pulses. Angle dispersion of the signals was compensated into one white-continuum beam by modifying a conventional 4f configuration. Spectral phase of the signal was measured by spectral phase interferometry for direct electric-field reconstruction. Isolated pulses with 25 fs duration at 1 kHz were generated only by appropriately aligning the angle-dispersion compensator. This result opens the possibility of the generation of subfemtosecond pulses in the visible region.

Isolated attosecond pulse generation by monocycle pumping: the use of a harmonic region with minimum dispersion

“…It seems that such spectral phase modulation is a general phenomenon in the coherent light wave interaction based on the multiorder nonlinear optical processes. For example, it was reported that, in the multiple-coherent anti-Stokes Raman scattering from the dielectric crystal, the steplike spectral phase modulation is experimentally observed at each Nth order when two different waves are generated by neighbororder nonlinear polarizations P ðNÞ and P ðNþ1Þ and overlapped spectrally [36]. This is because each nonlinearly induced Nthorder polarization P ðNÞ has a phase shift.…”

Broadband Light Generation in Raman-active Crystals Driven by Femtosecond Laser Fields

“…Then we can use a pulse shaper, such as Dazzler (FASTLITE) to combine the sidebands generated by the chirped pulse excitation. For the angled output, one possible scheme is combine the generated sidebands using a 4-f grating setup, as has been demonstrated recently (Matsubara et al, 2008;Weigand et al, 2009). …”

“…Great progress has been made recently toward synthesis of ultrashort, even few-cycle pulses using Raman crystal. For example, last year Matsubara et al have demonstrated promising Fourier synthesizer using multiple CARS signals obtained in a LiNbO 3 crystal at room temperature, and generated isolated pulses with 25 fs duration at 1 kHz repetition rate (Matsubara et al, 2008). Very recently, they just realized the generation of pulses in the 10 fs regime using multicolor Raman sidebands in KTaO 3 (Matsubara et al, 2009).…”

Generation of ultrashort optical pulses in the10 fs regime using multicolor Raman sidebands in KTaO_3

“…Recently, we have overcome the problem and succeeded in generating an isolated 25 fs pulse using the "conventional" multiple CARS signals in a single crystal of LiNbO 3 , where both the angle dispersion and the temporal dispersion compensation were achieved by a configuration with one spherical mirror and a grating [7]. In the present Letter, we report the drastic shortening of the pulse duration down to 13 fs, which has been achieved by the use of a new type of multiple CARS signal, called Raman-Nathlike (RN) CARS, from KTaO 3 crystal.…”

“…The diffracted beam was collimated by a spherical mirror with a 500 mm focal length (SM2). In the SPIDER measurement [7], the relative time delay of two replicas was 667 fs, the spectral shear was 3.18 THz ͑106 cm −1 ͒, and the spectral shift given by the chirped reference pulse (divided output from the amplifier) was 366 THz. Figure 3 shows the intensity spectrum and the spectral phase of the angle-dispersion compensated CARS beam.…”