排序方式: 共有105条查询结果,搜索用时 15 毫秒
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A phase retrieval algorithm which only needs to measure the intensity distribution at two positions to be effective is used to reconstruct the laser wave-front.Results are obtained from the phase retrieval algorithm in the visible band and the effects of the measurement error on the phase retrieval process are simulated.The algorithm is not sensitive to absolute amplitude measurement error,but is sensitive to the relative distribution of light intensity. 相似文献
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非常偏振光在单轴晶体表面的反射-透射研究 总被引:8,自引:0,他引:8
为分析非常偏振光在晶体表面的能量损耗,给出一种求解反射率和透射率的方法,即根据电磁场的边值关系以及晶体的双折射和双反射现象,求解晶体光轴在入射面内时,非常偏振光从各向同性介质入射到晶体和从晶体出射到各向同性介质两种情况的反射率和透射率的方法,并给出反射率和透射率的解析解,同时得到对于晶体光轴在入射面内的情况,光轴的取向对非常偏振光反射率的大小几乎没有影响,但对产生全反射的临界角θc影响较大的结论。实验上用LiNbO3晶体验证了非常偏振光从各向同性介质入射到晶体时的反射率公式。求解方法简单实用,所给的表达式具有一般性,可以直接使用。 相似文献
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体全息光栅透镜的设计和应用 总被引:10,自引:8,他引:2
设计了一种新型的体全息光栅透镜, 在一块光学平板(体全息记录材料)内可以将输入光束产生横向传输并聚焦, 或对输入光点产生横传的准直. 它由一束平面波和一束球面波正交入射到光学平板上干涉形成的. 研究了该体全息透镜的光栅间距变化情况, 为设计和制备体全息光栅透镜及相关器件提供了理论依据. 基于两光束耦合波理论, 得到了该光栅透镜的耦合波方程, 近似计算了该透镜的衍射效率及其达到高衍射效率时透镜的最佳尺寸. 最后, 讨论了该透镜在集成光学等领域中的应用. 相似文献
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It is rare for a conventional direct detection method to measure the transmittance uniformity of mirrors with rigorous standards, especially to meet the requirement of transmittance/reflectance and phase detection simultaneously. In this study, a new method of self-calibrated balanced heterodyne detection(SCBHD) is proposed. It can be self-calibrated by a two-channel structure to overcome the environmental effects in large optics scanning detection by employing highly accurate heterodyne interference. A typical transmittance measurement experiment was performed at 1053 nm wavelength via SCBHD. A standard deviation(SD) of 0.038% was achieved in the preliminary experiment. The experimental results prove to reduce the SD by approximately two orders of magnitude compared with the conventional direct detection method in the same condition. The proposed method was verified as being promising not only for its wider dynamic measurement range and its higher accuracy but also for its simultaneous transmittance and phase detection ability. 相似文献
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对光折变全息记录特别是双中心全息记录中90°记录结构下较低的衍射效率进行了研究,采用局域衍射理论对90°记录结构的衍射进行了分析,表明在同样的折射率变化和2 mm的光束宽度的情况下,只有当折射率光栅振幅大于10^-4时,90°记录结构衍射效率才能够与小角度透射记录结构的衍射效率大致相当。针对环境干扰导致的干涉条纹振动影响光栅记录,提出了有效调制度概念,根据分析90°记录结构的干涉条纹间距很小,容易受外界环境干扰而导致低的折射率变化率,因此应采用主动条纹锁定系统。此外在双中心全息记录中,微观光学参量的优化对衍射效率影响也很重要。 相似文献
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根据双中心带输运模型,对(Ce,Cu):LiNbO3晶体双中心非挥发全息记录进行了理论研究与优化。推导了(Ce,Cu):LiNbO3晶体的微观参量,采用数值方法通过严格求解模拟双中心带输运方程来模拟全息记录过程。分析了记录过程中,记录与敏化光强、Ce和Cu掺杂浓度以及晶体微观参量对(Ce,Cu):LiNbO3晶体双中心全息记录的影响。发现(Ce,Cu):LiNbO3晶体非挥发全息记录中实现高衍射效率与固定效率的主导因素是深中心Cu,在记录过程中,深中心Cu建立起了很强的空间电荷场。数值模拟的结果经过实验验证,最高饱和与固定衍射效率别为60.5%和53.8%。 相似文献
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A laser beam at wavelength 647nm is focused on a sample of 5mol% MgO-doped lithium niobate crystal for domain inversion by a conventional external electric field. In this case, a reduction of 36% in the electric field required for domain nucleation (nucleation field) is observed. To the best of our knowledge, it is the longest wavelength reported for laser-induced domain inversion. This extends the spectrum of laser inducing, and the experimental results are helpful to understand the nucleation dynamics under laser illumination. The dependence of nucleation fields on intensities of laser beams is analysed in experiments. 相似文献
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实验研究了掺杂组份比对LiNbO3∶Cu∶Ce晶体非挥发全息记录性能的影响。结果表明,在全息记录过程中,掺杂组份比通过改变晶体的紫外光吸收特性而引起全息记录性能的改变。增加 LiNbO3∶Cu∶Ce晶体中 Cu和 Ce的掺杂组份比会导致晶体对紫外光吸收的增强,进而提高了全息记录灵敏度和固定衍射效率。在弱氧化处理的掺有CuO和Ce2O3 的质量分数分别为0. 085%和0. 011%的LiNbO3∶Ce∶Cu晶体中,得到了最高的固定衍射效率ηf=32%和记录灵敏度S=0 .022 cm/J。 相似文献