Spectrometers are a key device in modern scientific research and industrial applications. To further expand their range of applications, researchers have proposed a dual-channel spectrometer that incorporates eight subgratings, replacing the mechanical moving parts used in traditional designs. Two sets of quadrifold spectra are used for diffraction and imaging in the upper and lower focal plane of the Dhyana 90A camera, respectively. The quantum efficiency of the camera at 400nm is about 90%. In addition to the cost-effective advantages of the spectroscopic system, the compact design of the spectrometer enables simultaneous measurement of multiple spectra.
Fig 1 Schematic illustration of the spectrometer system. (a) S1 and S2 are two independent optical slits. G1and G2 are two sets of gratings, each consisting of 4 sub-gratings. The 4-folded spectral lines from G1 and G2 are imaged with high resolution on the upper and lower parts, respectively, of the focal plane of the BSI-CMOS array detector. (b) One set of optical elements (S1, G1, mirrors 1 and 2, and filter set F) is arranged such that the spectral lines of channel 1 are imaged on the upper part of the focal plane of the BSI-CMOS detector D. The gray-colored positions shown in F1 and F2 in (a) are blank (without filters)
Fig 2 Photograph of the compact spectrometer constructed in accordance with the proposed design
Analysis of imaging technology
However, spectrometers need to measure more than one light signals at the same time in some situations, Conventional detector measurement in different time intervals will suffer from the time-related errors or errors induced by changing light paths. And it is hard to use different detectors to realize the same quantum efficiency with different environmental conditions. Therefore, to overcome these difficulties, researchers study a novel compact spectrometer that is based on Dhyana 90A. The Dhyana 90A features a wide spectral range (200-950 nm detection wavelength), high frame rate (24 frames per second), high resolution (better than 0.1nm/ pixel), and a 16-bit high dynamic range. This use of an advanced two-dimensional BSI-CMOS array detector shared by multiple spectral channels hope to represent a future trend of advanced spectrometer development.
Zang KY, Yao Y, Hu ET, Jiang AQ, Zheng YX, Wang SY, Zhao HB, Yang YM, Yoshie O, Lee YP, Lynch DW, Chen LY. A High-Performance Spectrometer with Two Spectral Channels Sharing the Same BSI-CMOS Detector. Sci Rep. 2018 Aug 23;8(1):12660. doi: 10.1038/s41598-018-31124-y. PMID: 30139954; PMCID: PMC6107652.