Dispersion Characteristics of the Multi-mode Fiber-fed VIPA Spectrograph
Dispersion Characteristics of the Multi-mode Fiber-fed VIPA Spectrograph
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DOI：
10.3847/1538-3881/accc30
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发表时间：
2023-05
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影响因子：
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通讯作者：
Xiaoming Zhu;D. Lin;Zhongnan Zhang;Xintong Xie;Jinping He
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作者：
Xiaoming Zhu;D. Lin;Zhongnan Zhang;Xintong Xie;Jinping He
在天文学中，一个高分辨率(>；105)、多模光纤馈电的大型望远镜和合理尺寸的光谱仪是可取的。本文对多模光纤馈电虚拟成像相控阵(VIPA)光谱仪的色散特性进行了理论和实验研究。本实验室自行设计并建造了一台工作波长为750∼770 nm的多模光纤馈电VIPA光谱仪。用自制的环形Yb光纤激光器频率梳(重复频率808MHZ)校准后，芯径为∅=10、25、50和10~5μm的多模光纤馈电的光谱分辨率与单模光纤相当，即=7.62×10~5∼8.97×10~5，传输效率相当。这从实验上证实，与埃谢尔光谱仪相比，输入光纤的纤芯直径对光谱分辨率的影响要小得多。还发现VIPA光谱仪的衍射包络依赖于光源的相干性，点扩展函数的宽度与探测器上的空间位置成反比。由于VIPA光谱仪在主色散方向上没有成像过程，光谱分辨率对输入狭缝的宽度或光纤直径不敏感。这使得VIPA光谱仪成为在非常大的望远镜上获得超高光谱分辨率(>；3×10~5)的一种很有前途的仪器。
A high-resolution ( >105 ), multi-mode fiber-fed spectrograph on large telescopes with a reasonable size is desirable in astronomy. In this work, the dispersion characteristics of a multi-mode fiber-fed Virtually Imaged Phased Array (VIPA) spectrograph are studied theoretically and experimentally. A VIPA spectrograph, fed by multi-mode optical fibers with the operating wavelength at 750 ∼ 770 nm, is designed and built in our laboratory. After calibration with a homemade Yb:fiber ring laser frequency comb (with a repetition frequency of 808 MHz), the measured spectral resolution fed by multi-mode fibers with core diameters ∅=10 , 25, 50, and 105 μm is comparable with that of the single-mode fiber, i.e., =7.62×105∼8.97×105 , with equivalent transmission efficiencies. This verifies experimentally that the spectral resolution is much less affected by the core diameters of the input fibers when compared with that of échelle spectrographs. It is also found that the diffraction envelope of the VIPA spectrograph relies on the coherence of light sources and the width of the point-spread function is inversely proportional to the spatial position on the detector. Since the VIPA spectrograph has no imaging process in the main dispersion direction, the spectral resolution is insensitive to the width of the input slit or the fiber diameter. This makes the VIPA spectrograph a promising instrument to attain an ultra-high spectral resolution ( >3×105 ) on very large telescopes.