Acta Optica Sinica, Volume. 40, Issue 23, 2312005(2020)
Optical Design of Solar Extreme Ultraviolet Normal-Incidence Broadband Imaging Spectrometer with Non-Rowland Circle Mounting
Concave grating imaging spectrometers operating at conventional Rowland circle mounting have excellent on-axis imaging performances. However, such spectrometers have been found to possess poor off-axis imaging performances as a result of the existence of large off-axis grating aberrations, which are not suitable for spatial and spectral imaging under a large off-axis field of view (FOV) and a broad band. Based on the aberration correction theory of toroidal varied line-space gratings operating at non-Rowland circle mounting, we designed a solar extreme ultraviolet (EUV) normal-incidence imaging spectrometer with a large off-axis FOV and a broad band. Specifically, this instrument can provide excellent imaging with high spatial and spectral resolutions for EUV spectroscopic observations of the solar corona and transition region. Besides, the instrument has only two reflective surfaces with periodic SiC/Al multilayer coating, which minimizes the loss of photon flux in the EUV band and improves the transmission efficiency of the instrument greatly. Finally, this unprecedented spectrometer, with an aperture of 100 mm and the operating bands of 40-47 nm, 53-60 nm, and 66-73 nm, achieves a spatial resolution and a spectral resolution better than 0.55″ and 30×10 -4 nm respectively, providing ultrahigh resolution imaging over the off-axis FOV of 18' along the slit.
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Yangguang Xing, Lin Li, Jilong Peng, Shanshan Wang, Yinuo Cheng. Optical Design of Solar Extreme Ultraviolet Normal-Incidence Broadband Imaging Spectrometer with Non-Rowland Circle Mounting[J]. Acta Optica Sinica, 2020, 40(23): 2312005
Category: Instrumentation, Measurement and Metrology
Received: Jul. 7, 2020
Accepted: Aug. 28, 2020
Published Online: Dec. 1, 2020
The Author Email: Li Lin (bit421@bit.edu.cn), Peng Jilong (JL_Peng@hotmail.com), Wang Shanshan (wshan@bit.edu.cn)