Absolute detector-based spectrally tunable radiant source using digital micromirror device and supercontinuum fiber...

Area of Science:

• Spectroradiometry
• Optical Engineering
• Atmospheric Science

Background:

• Advancements in absolute detector-based spectroradiometric calibration are crucial for quantitative spectral remote sensing.
• Existing calibration sources face limitations in brightness and spectral tunability for diverse remote sensing applications.

Purpose of the Study:

• To develop a high-brightness, spectrally tunable radiant source for calibrating remote sensing instruments.
• To meet the demands for spectral simulations of natural scenes like the sun and atmosphere.

Main Methods:

• Utilized a supercontinuum fiber laser for high spectral radiance.
• Incorporated a digital micromirror device (DMD) for spectral tunability and dual working modes (narrow-band and broad-band).
• Employed cryogenic absolute radiometer traceability for calibration.

Main Results:

• Achieved spectral radiance 20 times higher than conventional sources (tungsten lamps, xenon lamps, LEDs).
• Demonstrated superior stability of better than ±0.3%/h.
• Estimated spectral radiance uncertainty: <1.87% at 350 nm to 0.85% at 750 nm.

Conclusions:

• The developed spectrally tunable radiant source significantly improves spectroradiometric calibration accuracy and versatility.
• This technology advances calibration capabilities for ground-based, aeronautics-based, and aerospace-based remote sensing.
• Offers a substantial improvement over standard lamp-based calibration methods.