Stray Light

Optical systems must be analyzed to determine and reduce the amount of unwanted light to improve performance. SDL has the expertise and facilities necessary to predict and measure the off-axis rejection performance of space-borne telescopes. SDL has performed stray light design and analysis on many successful systems.


  • Non-sequential ray tracing models (e.g., Zemax) integrate and predict sensor stray light rejection performance
    • Incorporates BRDFs derived from surface roughness and particulate contamination levels (derived from Mie models)
    • Predicts off-axis sensor response to albedo, earth emissions, atmospheric bands, solar radiance, zodiacal backgrounds, and thermal self-emission
  • Black Hole Stray Light Measurement facility validates models with actual sensor optics
    • Tests sensors with up to 24” diameter aperture over IR, visible, or UV spectral range
    • Facility located in ISO 5 (Class 100) clean room enables testing of pristine optics
    • Testing & modeling iterations identify and correct scatter problems or vignetted surfaces
    • Partial automation speeds up test times
    • Can be transported to customer locations



Sounding of the Atmosphere using Broadband Emission Radiometry

SABER, a 10-channel infrared (1.27 to 16.9 µm) radiometer, is one of four instruments on NASA's TIMED mission, which is dedicated to study the dynamics of the Mesosphere and Lower Thermosphere (MLT) portion of the Earth's atmosphere.