多层电介质衍射光栅高功率激光辐照特性研究
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摘要
多层电介质反射式衍射光栅作为光谱合成系统的核心元件,在高功率激光辐照下的表面形变将导致其衍射特性改变,进而影响系统合成光束质量和衍射效率。搭建泰曼-格林干涉仪探测在高功率激光辐照下衍射光栅表面的干涉条纹,经图像处理及泽尼克多项式拟合实现光栅表面形貌的重建。采用高功率光纤激光辐照加热光栅,测量另一光束经过热畸变光栅后的光束质量和衍射效率演变。结果表明,在高功率激光辐照下光栅表面形变高度分布为高斯型,辐照功率密度3kW/cm~2时,干涉条纹对应区域内的光栅表面在垂直方向上隆起,最大高度为127nm。表面形变引起衍射光束质量因子M2退化,这种退化主要来自衍射光远场发散角的增大。光栅衍射效率波动幅度小于1.8%。
Multilayer dielectric diffraction grating is the most important optical element in spectral beam combining system.The surface distortion of grating under high power laser irradiation will change its diffraction characteristic,which will influence the beam quality and diffraction efficiency of the combining system. We establish an experimental setup of Twyman-Green interferometer to measure the interference fringes on the diffraction grating surface,under the high power laser irradiation.Based on the image processing and Zernike polynomial fitting method,the grating surface profile is reconstructed.With the high power laser heating the grating and another laser measuring the beam quality and diffraction efficiency degradation,the results show that the grating surface deformation distribution conforms to Gaussian model,when the irradiance power density is 3 kW/cm~2,the maximum distortion is evaluated to 127nm,which leads to the diffraction beam quality factor M2 degradation.The degradation is mainly due to the increase of angle divergence after diffraction.The change of diffraction efficiency is less than 1.8%,which is basically unchanged.
Multilayer dielectric diffraction grating is the most important optical element in spectral beam combining system.The surface distortion of grating under high power laser irradiation will change its diffraction characteristic,which will influence the beam quality and diffraction efficiency of the combining system. We establish an experimental setup of Twyman-Green interferometer to measure the interference fringes on the diffraction grating surface,under the high power laser irradiation.Based on the image processing and Zernike polynomial fitting method,the grating surface profile is reconstructed.With the high power laser heating the grating and another laser measuring the beam quality and diffraction efficiency degradation,the results show that the grating surface deformation distribution conforms to Gaussian model,when the irradiance power density is 3 kW/cm~2,the maximum distortion is evaluated to 127nm,which leads to the diffraction beam quality factor M2 degradation.The degradation is mainly due to the increase of angle divergence after diffraction.The change of diffraction efficiency is less than 1.8%,which is basically unchanged.
引文
[1]Limpert J,Liem A,Zellmer H,et al.500 Wcontinuous-wave fiber laser with excellent beam quality[J].Electronics Letters,2003,39(8):645-647.
[2]Jeong Y,Sahu J,Payne D,et al.Ytterbium-doped large-core fiber laser with 1.36kW continuous-wave output power[J].Optics Express,2004,12(25):6088-6092.
[3]Shiner B.The impact of fiber laser technology on the world wide material processing market[C].CLEO:2013Technical Digest,OSA,2013,AF2J.1.
[4]Dawson J W,Messerly M J,Beach R J,et al.Analysis of the scalability of diffraction-limited fiber lasers and amplifiers to high average power[J].Optics Express,2008,16(17):13240-13266.
[5]Taverner D,Richardson D J,Dong L,et al.158μJ pulses from a single transverse mode,large mode-area EDFA[J].Optics Letters,1997,22:378-380.
[6]Savageleuchs M,Afzal R,Honea E.Threshold power and fiber degradation induced modal instabilities in high-power fiber amplifiers based on large mode area fibers[J].Proceedings of SPIE,The International Society for Optical Engineering,2014,8961:89611R.
[7]Fan T Y.Laser beam combining for high-power,high-radiance sources[J].IEEE Journal of Selected Topics in Quantum Electronics,2005,11(3):567-577.
[8]Augst S J,Goyal A K,Aggarwal R L,et al.Wavelength beam combining of ytterbium fiber lasers[J].Optics Letters,2003,28(5):331-3.
[9]Sevian A,Andrusyak O,Ciapurin I,et al.Efficient power scaling of laser radiation by spectral beam combining[J].Optics Letters,2008,33(4):384-6.
[10]Volodin B L,Dolgy S V,Melnik E D,et al.Wavelength stabilization and spectrum narrowing of high-power multimode laser diodes and arrays by use of volume Bragg gratings[J].Optics Letters,2004,29(16):1891-3.
[11]Perry M D,Shannon C,Shults E,et al.High-efficiency multilayer dielectric diffraction gratings[J].Optics Letters,1995,20(8):940-2.
[12]Hehl K,Bischoff J,Mohaupt U,et al.High-efficiency dielectric reflection gratings:design,fabrication,and analysis[J].Applied Optics,1999,38(30):6257-71.
[13]Britten J A,Perry M D,Shore B W,etal.High-efficiency dielectric multilayer gratings optimized for manufacturability and laser damage threshold[J].Proceedings of SPIE,The International Society for Optical Engineering,1996:511-520.
[14]Shan Baozhong,Wang Shuyan,Niu Hanben,et al.Zernike polynomial fitting method and its application[J].Optics and Precision Engineering,2002,10(3):318-323.单宝忠,王淑岩,牛憨笨,等.Zernike多项式拟合方法及应用[J].光学精密工程,2002,10(3):318-323.
[15]Mo Weidong,The principle of fitting interferogram with Zernike polynomials[J].Journal of Air Force Engineering University(Natural Science Edition),2002,3(3):35-38.莫卫东.Zernike多项式拟合干涉波面的基本原则[J].空军工程大学学报·自然科学版,2002,3(3):35-38.
[16]Yang L,Wu Z,Zhang B.Influence of thermal deformation of a multilayer dielectric grating on a spectrally combined beam[J].Applied Optics,2016,55(32):9091-9100.
[2]Jeong Y,Sahu J,Payne D,et al.Ytterbium-doped large-core fiber laser with 1.36kW continuous-wave output power[J].Optics Express,2004,12(25):6088-6092.
[3]Shiner B.The impact of fiber laser technology on the world wide material processing market[C].CLEO:2013Technical Digest,OSA,2013,AF2J.1.
[4]Dawson J W,Messerly M J,Beach R J,et al.Analysis of the scalability of diffraction-limited fiber lasers and amplifiers to high average power[J].Optics Express,2008,16(17):13240-13266.
[5]Taverner D,Richardson D J,Dong L,et al.158μJ pulses from a single transverse mode,large mode-area EDFA[J].Optics Letters,1997,22:378-380.
[6]Savageleuchs M,Afzal R,Honea E.Threshold power and fiber degradation induced modal instabilities in high-power fiber amplifiers based on large mode area fibers[J].Proceedings of SPIE,The International Society for Optical Engineering,2014,8961:89611R.
[7]Fan T Y.Laser beam combining for high-power,high-radiance sources[J].IEEE Journal of Selected Topics in Quantum Electronics,2005,11(3):567-577.
[8]Augst S J,Goyal A K,Aggarwal R L,et al.Wavelength beam combining of ytterbium fiber lasers[J].Optics Letters,2003,28(5):331-3.
[9]Sevian A,Andrusyak O,Ciapurin I,et al.Efficient power scaling of laser radiation by spectral beam combining[J].Optics Letters,2008,33(4):384-6.
[10]Volodin B L,Dolgy S V,Melnik E D,et al.Wavelength stabilization and spectrum narrowing of high-power multimode laser diodes and arrays by use of volume Bragg gratings[J].Optics Letters,2004,29(16):1891-3.
[11]Perry M D,Shannon C,Shults E,et al.High-efficiency multilayer dielectric diffraction gratings[J].Optics Letters,1995,20(8):940-2.
[12]Hehl K,Bischoff J,Mohaupt U,et al.High-efficiency dielectric reflection gratings:design,fabrication,and analysis[J].Applied Optics,1999,38(30):6257-71.
[13]Britten J A,Perry M D,Shore B W,etal.High-efficiency dielectric multilayer gratings optimized for manufacturability and laser damage threshold[J].Proceedings of SPIE,The International Society for Optical Engineering,1996:511-520.
[14]Shan Baozhong,Wang Shuyan,Niu Hanben,et al.Zernike polynomial fitting method and its application[J].Optics and Precision Engineering,2002,10(3):318-323.单宝忠,王淑岩,牛憨笨,等.Zernike多项式拟合方法及应用[J].光学精密工程,2002,10(3):318-323.
[15]Mo Weidong,The principle of fitting interferogram with Zernike polynomials[J].Journal of Air Force Engineering University(Natural Science Edition),2002,3(3):35-38.莫卫东.Zernike多项式拟合干涉波面的基本原则[J].空军工程大学学报·自然科学版,2002,3(3):35-38.
[16]Yang L,Wu Z,Zhang B.Influence of thermal deformation of a multilayer dielectric grating on a spectrally combined beam[J].Applied Optics,2016,55(32):9091-9100.