对比用于极大望远镜行星相机和光谱仪（ELT-PCS）系外行星直接成像的两种积分场单元（IFU）技术的对比度性能
Comparing the contrast performance of two IFU technologies for exoplanet direct imaging with ELT-PCS
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中文总结 AI 辅助
本研究开发模块化实验室测试平台，对比图像切片器与微透镜阵列两种IFU技术用于ELT-PCS系外行星直接成像的对比度性能，发现图像切片器经光谱反卷积后在4λ/D处增益达3.4倍，后续将研究自适应光学残差的影响。
中文摘要 AI 辅助
极大望远镜行星相机和光谱仪（ELT-PCS）仪器的一项关键科学目标是对附近M型和K型矮星周围反射光中的岩质系外行星进行成像。这些观测需要在100毫角秒（mas）角分辨率下达到10^(-9)的对比度，在10 mas角分辨率下达到10^(-8)的对比度。为实现这种极端性能，必须仔细评估仪器的每一项设计选择。对于ELT-PCS的科学仪器而言，最关键的设计选择或许是采用哪种积分场单元（IFU）技术。为此，我们开发了一个模块化的实验室级积分场摄谱仪测试平台，用于对比两种流行的IFU技术——图像切片器和微透镜阵列的性能。该测试平台配备了Lyot日冕仪和空间光调制器，以模拟高对比度成像系统，该系统将衍射极限的点扩散函数（PSF）图像馈送给每个IFU。每个IFU与摄谱仪耦合，使用图像切片器时摄谱仪的分辨率R约为3000，使用微透镜阵列时R约为100。我们描述了每种IFU设计的校准和数据处理流程，并给出了对比度对比的初步结果。微透镜阵列在小于6λ/D的角分辨率下实现了更深的对比度；而图像切片器通过应用光谱反卷积在小角分辨率下获得了更大的增益，在4λ/D处的增益达到3.4倍，光谱反卷积还使对比度曲线接近探测器噪声底。后续工作将重点对微透镜阵列IFU进行完全控制的表征，并更全面地研究自适应光学残差对对比度的影响。
英文摘要
A key science goal for the Planetary Camera and Spectrograph (ELT-PCS) instrument is to image rocky exoplanets in reflected light around nearby M- and K-dwarfs. These observations will require a contrast of 10^(-9) at 100 mas angular separation, and 10^(-8) at 10 mas. To achieve such an extreme performance, every instrument design choice must be carefully evaluated. For ELT-PCS's science instruments, perhaps the most critical design choice is which integral field unit (IFU) technology to use. To this end, we have developed a modular, lab-based integral field spectrograph test bench with which to compare the performance of two popular IFU technologies: image slicers and lenslet arrays. The test bench implements a Lyot coronagraph and a spatial light modulator to simulate a high-contrast imaging system, which feeds each IFU with a diffraction-limited PSF image. Each IFU is coupled to the spectrograph, which achieves R ~ 3000 with the image slicer and R ~ 100 with the lenslet array. The calibration and data reduction for each IFU design are described and the initial results of a contrast comparison are presented. The lenslet array achieves a deeper contrast at angular separations of less than 6 lambda/D. The image slicer, however, gains more at small separations from applying spectral deconvolution, with a 3.4x greater gain at 4 lambda/D. Spectral deconvolution further yields a contrast curve close to the detector noise floor. Further work will focus on carrying out a fully-controlled characterisation of the lenslet array IFU and a more comprehensive study into the effects of adaptive optics residuals on the contrast.
