Selective excitation of coherent anti-Stokes Raman scattering from the benzene solution is achieved by adaptive pulse shaping based on genetic algorithm, and second harmonic generation frequency-resolved optical gati...Selective excitation of coherent anti-Stokes Raman scattering from the benzene solution is achieved by adaptive pulse shaping based on genetic algorithm, and second harmonic generation frequency-resolved optical gating （SHG-FROG） technique is adopted to characterize the original and optimal laser pulses. The mechanism for two-pulse coherent mode-selective excitation of Raman scattering is experimentally investigated by modulating the pump pulse in the frequency domain, and it is indicated that two-pulse coherent mode-selective excitation of Raman scattering mainly depends on the effective frequency components of the pump pulse related to specific vibrational mode. The experimental results suggest that two-pulse CARS has good signal-to-background ratio and high sensitivity, and it has attractive potential applications in the complicated molecular system.展开更多
High resolution mode-selective excitation in the mixture of C6H6 （992 cm^-1） and C6D6 （945 cm^-1） is experimentally achieved by adaptive femtosecond pulse shaping based on the genetic algorithm （GA）, and second ...High resolution mode-selective excitation in the mixture of C6H6 （992 cm^-1） and C6D6 （945 cm^-1） is experimentally achieved by adaptive femtosecond pulse shaping based on the genetic algorithm （GA）, and second harmonic generation frequency-resolved optical gating （SHG-FROG） is adopted to characterize the original and optimal laser pulses, and its mechanism is experimentally validated by tailoring the frequency components of the pump pulses at the Fourier plane. It is indicated that two-pulse coherent mode-selective excitation of the Raman scattering mainly depends on the effective frequency components of the pump pulse related to specific molecular vibrational mode. The experimental results have attractive potential applications in the complicated molecular system.展开更多
The structural deformation of NO2 group induced by an intense femtosecond laser field of liquid nitromethane（NM）molecule is detected by time-and frequency-resolved coherent anti-Stokes Raman spectroscopy（CARS） tec...The structural deformation of NO2 group induced by an intense femtosecond laser field of liquid nitromethane（NM）molecule is detected by time-and frequency-resolved coherent anti-Stokes Raman spectroscopy（CARS） technique with the intense pump laser. Here, we present the mechanism of molecular alignment and deformation. The CARS spectra and its FFT spectra of liquid NM show that the NO2 torsional mode couples with the CN symmetric stretching mode and that the NO2 group undergoes ultrafast structural deformation with a relaxation time of 195 fs. The frequency of the NO2 torsional mode in liquid NM（50.8±0.3 cm^-1） at room temperature is found. Our results prove the structural deformation of two groups in liquid NM molecule occur simultaneously in the intense laser field.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 10574046, the National Basic Research Programme of China under Grant Nos 2006CB806006 and 2006CB921105, the Programme for Changjiang Scholars and Innovative Research Team in University （PCSIRT）, the Programme for New Century Excellent Talents in University under Grant No NCET- 04-0420, the Doctoral Programme of High Education under Grant No 20050269011, Phosphor Programme sponsored by Shanghai Science and Technology Committee under Grant No 06QH14003.
文摘Selective excitation of coherent anti-Stokes Raman scattering from the benzene solution is achieved by adaptive pulse shaping based on genetic algorithm, and second harmonic generation frequency-resolved optical gating （SHG-FROG） technique is adopted to characterize the original and optimal laser pulses. The mechanism for two-pulse coherent mode-selective excitation of Raman scattering is experimentally investigated by modulating the pump pulse in the frequency domain, and it is indicated that two-pulse coherent mode-selective excitation of Raman scattering mainly depends on the effective frequency components of the pump pulse related to specific vibrational mode. The experimental results suggest that two-pulse CARS has good signal-to-background ratio and high sensitivity, and it has attractive potential applications in the complicated molecular system.
基金Supported by the National Natural Science Foundation of China under Grant No 10574046, the National Basic Research Programme of China under Grant Nos 2006CB806006 and 2006CB921105, the Programme for Changjiang Scholars and Innovative Research Team in University （PCSIRT）, the Programme for New Century Excellent Talents in University （NCET-04-0420）, the Doctoral Programme of High Education of China under Grant No 20050269011, the Phosphor Programme sponsored by Shanghai Science and Technology Committee （06QH14003）.
文摘High resolution mode-selective excitation in the mixture of C6H6 （992 cm^-1） and C6D6 （945 cm^-1） is experimentally achieved by adaptive femtosecond pulse shaping based on the genetic algorithm （GA）, and second harmonic generation frequency-resolved optical gating （SHG-FROG） is adopted to characterize the original and optimal laser pulses, and its mechanism is experimentally validated by tailoring the frequency components of the pump pulses at the Fourier plane. It is indicated that two-pulse coherent mode-selective excitation of the Raman scattering mainly depends on the effective frequency components of the pump pulse related to specific molecular vibrational mode. The experimental results have attractive potential applications in the complicated molecular system.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.21673211 and 21203047)the Foundation of Heilongjiang Bayi Agricultural University,China(Grant No.XZR2014-16)the Science Challenging Program of China(Grant No.JCKY2016212A501)
文摘The structural deformation of NO2 group induced by an intense femtosecond laser field of liquid nitromethane（NM）molecule is detected by time-and frequency-resolved coherent anti-Stokes Raman spectroscopy（CARS） technique with the intense pump laser. Here, we present the mechanism of molecular alignment and deformation. The CARS spectra and its FFT spectra of liquid NM show that the NO2 torsional mode couples with the CN symmetric stretching mode and that the NO2 group undergoes ultrafast structural deformation with a relaxation time of 195 fs. The frequency of the NO2 torsional mode in liquid NM（50.8±0.3 cm^-1） at room temperature is found. Our results prove the structural deformation of two groups in liquid NM molecule occur simultaneously in the intense laser field.
