CCD spectrometer folds spectral images from 200 to 1000 nm

摘要

In traditional spectrometers, grating or prism dispersion elements are rotated continuously in fine steps using a mechanical mechanism to scan the wavelength and achieve high-resolution spectral measurements. Although 2-D silicon-based charge-coupled-device (CCD) or complementary-metal-oxide-semiconductor (CMOS) detector arrays have been used to record many spectral lines at the same time in parallel data-acquisition mode, the effective spectral-measurement range is only 80 nm for a 26.8 X 28-mm CCD array for a dispersion of 3 nm/mm. But, using a special grating consisting of ten subgratings, researchers in the Department of Optical Science and Engineering at Fudan University (Shanghai, China) have succeeded in developing a high-resolution CCD spectrometer that folds dispersed spectral images ten times, without any mechanical moving parts, to cover the full 200- to 1000-nm working wavelength range with an acquisition time of less than 100 ms. The secret to the spectrometer system is its unique grating, designed to arrange ten spectral zones with different wavelength windows covering the 200-to-1000-nm range in sequence along the direction perpendicular to the spectral distribution, to fill the image plane of the 26.8 X 28-mm CCD array. The integrated grating structure consists of 10 subgratings at different angles of incidence, each with a density of 1200 grooves/mm. Each subgrating is approximately 60 X 5 mm, with the grooves parallel to the short side.