Wang Chen, Chen He, Zhang Yinchao, Chen Siying, Guo Pan, Wang Lifu
Appl Opt. 2019 Oct 1;58(28):7789-7794. doi: 10.1364/AO.58.007789.
Conventional Czerny-Turner spectrometers exhibit keystone distortion due to astigmatism, which affects their performance when a linear array photomultiplier tube (LaPMT) is used as the detector. We propose a novel optical design of a crossed Czerny-Turner spectrometer with a 32-channel LaPMT detector. We use convergent illumination of the grating to modify the astigmatism of the off-axis spherical mirrors, and the image spot radius at the central wavelength in the sagittal plane is matched with the width of the LaPMT. A first-order equation is derived for the elimination of the broadband keystone distortion. After optimization, the image size over the entire bandwidth matches well with the LaPMT size, which is consistent with the theory, and the spectral resolution is ∼4 nm per channel.
传统的 Czerny-Turner 光谱仪由于像散会出现梯形失真，当使用线性阵列光电倍增管（LaPMT）作为探测器时，这会影响其性能。我们提出了一种采用 32 通道 LaPMT 探测器的交叉 Czerny-Turner 光谱仪的新型光学设计。我们利用光栅的会聚照明来修正离轴球面镜的像散，并且使矢状面中中心波长处的像斑半径与 LaPMT 的宽度相匹配。推导了一个用于消除宽带梯形失真的一阶方程。经过优化后，整个带宽上的图像尺寸与 LaPMT 尺寸匹配良好，这与理论相符，并且光谱分辨率约为每通道 4 纳米。
