Acta Optica Sinica, Volume. 41, Issue 11, 1122001(2021)

Spectroscopic Imaging System in Mid-Wave Infrared Imaging Spectrometer on Geostationary Orbit

Jiacheng Zhu1,2, Weiqi Lu1,2, Zhicheng Zhao1,2, Xinhua Chen1,2、*, and Weimin Shen1,2
Author Affiliations
  • 1School of Optoelectronic Science and Engineering, Soochow University, Suzhou, Jiangsu 215006, China
  • 2Key Laboratory of Modern Optical Technology, Ministry of Education, Suzhou, Jiangsu 215006, China
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    Figures & Tables(17)
    Schematic of detector splicing of single spectroscopic imaging spectrometer
    Schematic of spectroscopic imaging spectrometer splicing
    Schematic of optical path of the mid-wave infrared spectroscopic imaging spectrometer. (a) Side view; (b) axial view
    Splicing schematic of spectroscopic imaging spectrometer
    Optical-mechanical model of the mid-wave infrared spectroscopic imaging spectrometer
    Center wavelength MTF curves at room temperature and cooling temperature. (a) Center wavelength MTF curve under 20 ℃; (b) center wavelength MTF curve under 160 K
    Slit and its microscope test chart
    Self-developed convex blazed diffraction grating and its groove shape test chart
    Grating diffraction efficiency curve
    Spectral performance test setup of prototype
    Advanced sub-spectrum lines at 830 nm
    • Table 1. Specifications of the MWIR imaging spectrometer

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      Table 1. Specifications of the MWIR imaging spectrometer

      ParameterValue
      Orbit height /km36000
      Swath width /km400
      Spectral range /μm3--5
      Spatial resolution /m50
      Spectral sampling distance /nm50
      Static MTF≥0.4@4 μm
      NETD/K≤0.2
      Smile /%<10
      Keystone /%<5
    • Table 2. Specifications of optical system

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      Table 2. Specifications of optical system

      ParameterValue
      Spectral range /μm3--5
      Total length of double slit /mm49
      Interval of double slit /mm6.9
      Slit width /μm24
      F number5.4
      Dispersive width /mm3.84
      System width /mm<98
    • Table 3. Main structural parameters and performance parameters of the spectroscopic imaging spectrometer

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      Table 3. Main structural parameters and performance parameters of the spectroscopic imaging spectrometer

      Specification and PerformanceValue
      Radius of M (RM) /mm218.56
      Radius of G (RG) /mm111.00
      Grating groove density /(line·mm-1)19.1
      Blazed angle of grating /(°)2.6
      Diffraction order-1
      Lateral displacement of slits /mm31.4 & 38.3
      Package size /(mm×mm×mm)88×168×180
      Smile /%<0.3
      Keystone /%<0.1
      MTF @20 ℃ @4 μm0.41
      RMS spot diameter @20 ℃ /μm<8
    • Table 4. Surface optical properties of optomechanical components

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      Table 4. Surface optical properties of optomechanical components

      ElementOptical property
      SlitReflectivity 90%
      M、FM1、FM2Reflectivity 98.5%Scattering coefficient 0.02%
      GDesigned diffraction efficiencyAbsorptivity 1.5%
      Mechanical frameAbsorptivity 90%Near-specular reflectivity 5%Lambert scattering rate 5%
    • Table 5. Ebackground and NETD of the spectroscopic imaging spectrometer change with the cooling temperature

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      Table 5. Ebackground and NETD of the spectroscopic imaging spectrometer change with the cooling temperature

      Tc /KEbackground /(W·mm-2)NETD /K
      2002.48×10-82.12
      1804.41×10-90.92
      1605.20×10-100.13
      1403.41×10-110.04
      1209.27×10-130.03
      1006.27×10-150.03
    • Table 6. Spectral performance test results of prototype

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      Table 6. Spectral performance test results of prototype

      ParameterIMAG1IMAG2
      Spectral sampling distance /nm50.049.9
      Max smile /μm1.21.5
      Max keystone /μm0.60.6
      MTF@632.8 nm@-6thorder@21 lp/mm0.830.81
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    Jiacheng Zhu, Weiqi Lu, Zhicheng Zhao, Xinhua Chen, Weimin Shen. Spectroscopic Imaging System in Mid-Wave Infrared Imaging Spectrometer on Geostationary Orbit[J]. Acta Optica Sinica, 2021, 41(11): 1122001

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    Paper Information

    Category: Optical Design and Fabrication

    Received: Nov. 30, 2020

    Accepted: Dec. 30, 2020

    Published Online: Jun. 7, 2021

    The Author Email: Chen Xinhua (xinhua_chen@suda.edu.cn)

    DOI:10.3788/AOS202141.1122001

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