Bi-directional reflectance and Raman characterizations of Spectralons with varying albedos

Area of Science:

• Optical remote sensing
• Materials science

Background:

• Spectralon plaques are widely used for calibrating instruments.
• Understanding their bi-directional reflectance distribution function (BRDF) is critical for accurate measurements.

Purpose of the Study:

• To measure the spectral BRDF of Spectralon plaques with varying reflectances (2-99%).
• To evaluate the Lambertian behavior of Spectralon plaques at different incident angles (0° and 60°).
• To assess the impact of Spectralon standards on the calibration of particulate samples.

Main Methods:

• Spectral BRDF measurements of eight Spectralon plaques from 350 to 2150 nm.
• Measurements conducted at incident zenith angles of 0° and 60°.
• Calibration of particulate samples using Spectralon standards.

Main Results:

• The 40% Spectralon showed the most Lambertian behavior at normal incidence (0°).
• The 99% Spectralon exhibited the best Lambertian behavior at a 60° incident angle.
• Calibrated reflectance values (REFF) of particulate samples were highest when using the 99% Spectralon plaque.

Conclusions:

• The choice of Spectralon plaque affects the absolute reflectance calibration of particulate samples.
• The 99% Spectralon plaque is recommended for achieving higher calibrated reflectance values, especially under non-normal incidence conditions.