In this paper we study the gain saturation induced mode-coupling control in solid state ring laser devices based on the stimulated Raman effect of the polar crystals in.order to realize solid state ring laser gyroscop...In this paper we study the gain saturation induced mode-coupling control in solid state ring laser devices based on the stimulated Raman effect of the polar crystals in.order to realize solid state ring laser gyroscopes. We theoretically investigate the mode coupling induced by gain saturation between clockwise （CW） and counterclockwise （CCW） propa- gating laser modes. Because the CW and CCW running waves are pumped with counter-propagating lasers respectively, the independent coexistence can be ensured.展开更多
Using the mean-field normalized Lugiato-Lefever equation,we theoretically investigate the dynamics of cavity soliton and comb generation in the presence of Raman effect and the third-order dispersion.Both of them can ...Using the mean-field normalized Lugiato-Lefever equation,we theoretically investigate the dynamics of cavity soliton and comb generation in the presence of Raman effect and the third-order dispersion.Both of them can induce the temporal drift and frequency shift.Based on the moment analysis method,we analytically obtain the temporal and frequency shift,and the results agree with the direct numerical simulation.Finally,the compensation and enhancement of the soliton spectral between the Raman-induced self-frequency shift and soliton recoil are predicted.Our results pave the way for further understanding the soliton dynamics and spectral characteristics,and providing an effective route to manipulate frequency comb.展开更多
The effect of solvent on surface enhanced Raman scattering [SERS) of colloidal silver has been studied. Experiments show that the intensity of SERS is related to the polarity and molecular constitution of the solvent....The effect of solvent on surface enhanced Raman scattering [SERS) of colloidal silver has been studied. Experiments show that the intensity of SERS is related to the polarity and molecular constitution of the solvent. The influence of solvent is due to the change of the adsorption quantity and adsorption intensity.展开更多
The Raman–Nath diffraction in acousto–optic effect was studied theoretically and experimentally in the paper. Up to now, each order of diffracted light in Raman–Nath diffraction was still considered simply to be ju...The Raman–Nath diffraction in acousto–optic effect was studied theoretically and experimentally in the paper. Up to now, each order of diffracted light in Raman–Nath diffraction was still considered simply to be just frequency-shifted and to be a plane wave. However, we find that the phase and frequency shifts occur simultaneously and individually in Raman–Nath diffraction. The findings demonstrate that, in addition to the frequency shift, the optical phase of each order of diffracted light is also shifted by the sound wave and fluctuates with the sound wave and is related to the location in the acoustic field from which the diffracted light originates. As a result, the wavefront of each order of diffracted light is modulated to fluctuate spatially and temporally with the sound wave. Obviously, these findings are significant for applications of Raman–Nath diffraction in acousto–optic effect because the optical phase plays an important role in optical coherence technology.展开更多
A theoretical study on oligopeptide chains of glycine-alanine by density functional theory（DFT） is given in this paper. Raman spectra of the oligopeptide chains are examined. The geometric structures, frontier orbit...A theoretical study on oligopeptide chains of glycine-alanine by density functional theory（DFT） is given in this paper. Raman spectra of the oligopeptide chains are examined. The geometric structures, frontier orbital, energy gap, atomic charge distribution, density of states and chemical activity of the side chain are studied at the B3LYP/6-31G（d） level. Results show that, with the number of residues increasing, vibrations of typical functional groups present Raman frequency shift, and the energy gap is gradually reduced. The HOMO and LUMO focus on the amino and carboxyl at the ends of oligopeptides. It is helpful for oligopeptides to self-assemble into chains. In addition, different residues（glycine or alanine） at the ends of chains result in the even-odd effect of orbital energy in the growth process. The size effects of physical and chemical properties only exist when the oligopeptides are shorter, and the phenomenon disappeared as the chain continues to grow.展开更多
We theoretically investigate the Doppler effect on optical bistability in an N-type active Raman gain atomic system inside an optical ring cavity. It is shown that the Doppler effect can greatly enhance the dispersion...We theoretically investigate the Doppler effect on optical bistability in an N-type active Raman gain atomic system inside an optical ring cavity. It is shown that the Doppler effect can greatly enhance the dispersion and thus create the bistable behaviour or greatly increase the bistable region, which has been known as the positive Doppler effect on optical bistability. In addition, we find that a positive Doppler effect can change optical bistability from the hybrid dispersion-gain type to a dispersive type.展开更多
文摘In this paper we study the gain saturation induced mode-coupling control in solid state ring laser devices based on the stimulated Raman effect of the polar crystals in.order to realize solid state ring laser gyroscopes. We theoretically investigate the mode coupling induced by gain saturation between clockwise （CW） and counterclockwise （CCW） propa- gating laser modes. Because the CW and CCW running waves are pumped with counter-propagating lasers respectively, the independent coexistence can be ensured.
基金Project supported by the National Key Research and Development Program of China (Grant Nos. 2017YFA0304203 and 2019YFA0705000)the National Natural Science Foundation of China (Grant Nos. 12004116 and 11804204)1331KSC
文摘Using the mean-field normalized Lugiato-Lefever equation,we theoretically investigate the dynamics of cavity soliton and comb generation in the presence of Raman effect and the third-order dispersion.Both of them can induce the temporal drift and frequency shift.Based on the moment analysis method,we analytically obtain the temporal and frequency shift,and the results agree with the direct numerical simulation.Finally,the compensation and enhancement of the soliton spectral between the Raman-induced self-frequency shift and soliton recoil are predicted.Our results pave the way for further understanding the soliton dynamics and spectral characteristics,and providing an effective route to manipulate frequency comb.
文摘The effect of solvent on surface enhanced Raman scattering [SERS) of colloidal silver has been studied. Experiments show that the intensity of SERS is related to the polarity and molecular constitution of the solvent. The influence of solvent is due to the change of the adsorption quantity and adsorption intensity.
基金Project supported by the National Natural Science Foundation of China(Grant No.61178089)the Science and Technology Program of the Educational Office of Fujian Province of China(Grant Nos.JB12012 and JB13003)
文摘The Raman–Nath diffraction in acousto–optic effect was studied theoretically and experimentally in the paper. Up to now, each order of diffracted light in Raman–Nath diffraction was still considered simply to be just frequency-shifted and to be a plane wave. However, we find that the phase and frequency shifts occur simultaneously and individually in Raman–Nath diffraction. The findings demonstrate that, in addition to the frequency shift, the optical phase of each order of diffracted light is also shifted by the sound wave and fluctuates with the sound wave and is related to the location in the acoustic field from which the diffracted light originates. As a result, the wavefront of each order of diffracted light is modulated to fluctuate spatially and temporally with the sound wave. Obviously, these findings are significant for applications of Raman–Nath diffraction in acousto–optic effect because the optical phase plays an important role in optical coherence technology.
基金Supported by the National Natural Science Foundation of China(No.60878063)the Program from Traditional Chinese Medicine Bureau of Guangdong Province(No.2008233)
文摘A theoretical study on oligopeptide chains of glycine-alanine by density functional theory（DFT） is given in this paper. Raman spectra of the oligopeptide chains are examined. The geometric structures, frontier orbital, energy gap, atomic charge distribution, density of states and chemical activity of the side chain are studied at the B3LYP/6-31G（d） level. Results show that, with the number of residues increasing, vibrations of typical functional groups present Raman frequency shift, and the energy gap is gradually reduced. The HOMO and LUMO focus on the amino and carboxyl at the ends of oligopeptides. It is helpful for oligopeptides to self-assemble into chains. In addition, different residues（glycine or alanine） at the ends of chains result in the even-odd effect of orbital energy in the growth process. The size effects of physical and chemical properties only exist when the oligopeptides are shorter, and the phenomenon disappeared as the chain continues to grow.
基金Project supported by the National Natural Science Foundation of China (Grant No. 60978013)the Shanghai Rising Star Project,China (Grant No. 11QA1407400)
文摘We theoretically investigate the Doppler effect on optical bistability in an N-type active Raman gain atomic system inside an optical ring cavity. It is shown that the Doppler effect can greatly enhance the dispersion and thus create the bistable behaviour or greatly increase the bistable region, which has been known as the positive Doppler effect on optical bistability. In addition, we find that a positive Doppler effect can change optical bistability from the hybrid dispersion-gain type to a dispersive type.
