空间引力波望远镜远场相位噪声抑制方法  

Method of Far-field Phase Noise Suppression for Space Gravitational Wave Detection Telescope

作　　者：陈胜楠 王春艳[1] 孙浩[1] 姜会林[1] Chen Shengnan;Wang Chunyan;Sun Hao;Jiang Huilin(School of Opto-Electronic Engineering,Changchun University of Science and Technology,Changchun,Jilin 13002323,China)

机构地区：[1]长春理工大学光电工程学院,吉林长春130033

出　　处：《光学学报》2023年第6期329-334,共6页Acta Optica Sinica

基　　金：吉林省教育厅资助(JJKH20220755KJ)。

摘　　要：空间引力波望远镜的波像差与指向抖动耦合产生的远场相位噪声是引力波探测的主要噪声源。基于其产生的理论机制,建立了噪声耦合系数与望远镜像差间的函数关系,提出了控制特定像差的优化策略。结合望远镜设计实例验证了该方法对抑制远场相位噪声的效果,当波前质量水平为λ/20(λ=1064nm)时,优化后的噪声耦合系数优于0.11 pm/nrad,较优化前降低了一个数量级,远优于指标要求,所提方法极大地提升了望远镜的远场相位稳定性。Objective Space-based gravitational-wave observatories(SGOs)promise to measure pico-meter variations in gigameter separations of a triangular constellation.Telescopes play a crucial role in transmitting and receiving laser beams measuring the constellation arms with heterodyne laser interferometry.The wavefront aberrations of optical telescopes are coupled with pointing jitter and induce noise in the far-field phase,which is one of the noise sources of the measurement.As a critical aspect to achieve the required comprehensive measuring stability,we theoretically analyze the mechanism of the far-field phase noise in this paper.And an optimization strategy of the optical telescope design in SGOs is proposed and verified,opening the way for comprehensive control of the phase noise in the design-to-manufacture process.Methods To analytically establish the relationship between the coupling coefficient and the aberrations in the form of polynomial expansions,the Fringe Zernike polynomials are adopted to represent the aberrations to construct and describe the wavefront error.Then the coupling coefficient defined as the modulus of the gradient of the far-field wavefront error is expressed as a polynomial function of the aberration coefficients and the tilts,which is further simplified based on the symmetry of the telescope.According to this relationship and the aberration characteristics of the telescope design residuals,the effect of different aberrations on the phase noise is evaluated,deriving that defocus,primary astigmatism,and primary spherical aberration are the keys to controlling the coupling coefficient.Thus,an optimization strategy based on key aberrations control is proposed.The effect of this method on the far-field phase noise suppressing is verified by design examples of the telescope.Results and Discussions The wavefront quality of the telescopes before and after optimization(Table 1)with the above strategy is at theλ/20(λ=1064nm)level.Before optimization,the far-field wavefront changes significantly wi

关 键 词：激光光学 望远镜 空间引力波探测 远场相位 耦合系数 

分 类 号：O439[机械工程—光学工程]