A band-stop angular filter(BSF)based on hump volume Bragg gratings(HVBGs)is proposed.Band-stop filtering in a two-stage amplifier laser system is discussed and simulated.Simulation results show that small-scale self-f...A band-stop angular filter(BSF)based on hump volume Bragg gratings(HVBGs)is proposed.Band-stop filtering in a two-stage amplifier laser system is discussed and simulated.Simulation results show that small-scale self-focusing effects in the laser system can be effectively suppressed with the BSF due to the control of fast nonlinear growth in a specific range of spatial frequencies in the laser beam.Near-field modulation of the output beam from the laser system was decreased from 2.69 to 1.37 by controlling the fast nonlinear growth of spatial frequencies ranging from 0.6 mm-1to 1.2 mm-1 with the BSF.In addition,the BSF can be used in a plug-and-play scheme and has potential applications in high-power laser systems.展开更多
The coupled wave theory for volume holographic grating with curved interference fringes has been proposed based on the Kogelnik’s coupled wave theory with the plane interference fringes. The formula about the magnitu...The coupled wave theory for volume holographic grating with curved interference fringes has been proposed based on the Kogelnik’s coupled wave theory with the plane interference fringes. The formula about the magnitude and directional angle of grating vector in arbitrary position of volume holographic grating with curved grating has been deduced. We found that the wavelength selectivity and angular selectivity may be different in different position of volume holographic curved stripe grating which depend on the angle between the propagation vector of reference beam and signal beam. The larger the angle, the greater the angle and wavelength selectivity, whereas the weaker.展开更多
Based on a modified coupled wave theory of Kogelnik, we have studied the diffraction of an ultrashort pulsed beam with an arbitrary polarization state from a volume holographic grating in photorefractive LiNbO3 crysta...Based on a modified coupled wave theory of Kogelnik, we have studied the diffraction of an ultrashort pulsed beam with an arbitrary polarization state from a volume holographic grating in photorefractive LiNbO3 crystals. The results indicate that the diffracted intensity distributions in the spectral and temporal domains and the diffraction efficiency of the grating are both changed by the polarization state and spectral bandwidth of the input pulsed beam. A method is given of choosing the grating parameters and input conditions to obtain a large variation range of the spectral bandwidth of the diffracted pulsed beam with an appropriate diffraction efficiency. Our study presents a possibility of using a volume holographic grating recorded in anisotropic materials to shape a broadband ultrashort pulsed beam by modulating its polarization state.展开更多
基金supported by the National Key R&D Program of China(No.2016YFF0100903)the National Natural Science Foundation of China(NSFC)(Nos.61775153,61705153,and 11504255)+1 种基金the Natural Science Foundation of Jiangsu Province(No.BK20141232)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘A band-stop angular filter(BSF)based on hump volume Bragg gratings(HVBGs)is proposed.Band-stop filtering in a two-stage amplifier laser system is discussed and simulated.Simulation results show that small-scale self-focusing effects in the laser system can be effectively suppressed with the BSF due to the control of fast nonlinear growth in a specific range of spatial frequencies in the laser beam.Near-field modulation of the output beam from the laser system was decreased from 2.69 to 1.37 by controlling the fast nonlinear growth of spatial frequencies ranging from 0.6 mm-1to 1.2 mm-1 with the BSF.In addition,the BSF can be used in a plug-and-play scheme and has potential applications in high-power laser systems.
文摘设计了一种基于棱镜-光栅-棱镜(Prism-Grating-Prism,PGP)分光器件的新型成像光谱仪.论述了此成像光谱仪的工作原理和结构形式,包括PGP、准直物镜和成像物镜的设计要求.PGP元件中采用体积相位全息透射光栅,可以获得高的衍射效率,并且能与棱镜较好地胶合.给出了此成像光谱仪的设计结果,其光谱范围为400～800 nm,像元光谱分辨率约1.6 nm,系统长度为85 mm.
文摘The coupled wave theory for volume holographic grating with curved interference fringes has been proposed based on the Kogelnik’s coupled wave theory with the plane interference fringes. The formula about the magnitude and directional angle of grating vector in arbitrary position of volume holographic grating with curved grating has been deduced. We found that the wavelength selectivity and angular selectivity may be different in different position of volume holographic curved stripe grating which depend on the angle between the propagation vector of reference beam and signal beam. The larger the angle, the greater the angle and wavelength selectivity, whereas the weaker.
基金Project supported by the State Key Development Program for Basic Research of China （Grant No 2002CCA03500）, and the National Natural Science Foundation of China （Grant No 60177016）.
文摘Based on a modified coupled wave theory of Kogelnik, we have studied the diffraction of an ultrashort pulsed beam with an arbitrary polarization state from a volume holographic grating in photorefractive LiNbO3 crystals. The results indicate that the diffracted intensity distributions in the spectral and temporal domains and the diffraction efficiency of the grating are both changed by the polarization state and spectral bandwidth of the input pulsed beam. A method is given of choosing the grating parameters and input conditions to obtain a large variation range of the spectral bandwidth of the diffracted pulsed beam with an appropriate diffraction efficiency. Our study presents a possibility of using a volume holographic grating recorded in anisotropic materials to shape a broadband ultrashort pulsed beam by modulating its polarization state.
