What are Diffusers?
Optical Diffusers are used to evenly distribute light, typically creating a lambertian emission profile.
Integrating spheres by nature diffusely scatter light. Making them prime candidates for diffuse surfaces. (see our blog on integrating spheres)
Transmissive and Reflective Diffusers
Transmissive (Forward Scattering) Diffuser
Transmissive diffusers usually function as volume diffusers, this involves a transmissive material with a series of scattering centers (ie. gas bubbles). For the example of opsira’s optical diffusers, the air bubbles within the diffuser causes light from a laser beam to experience quasi-random change of its optical phase. Higher density of bubbles will result in higher optical scattering which yields a more Lambertian source.
Reflective (Backward Scattering) Diffuser
Reflective diffusers function by having many microstructed imperfections on a surface, thus causing the light to reflect and scatter at different solid angles. One way of creating these imperfections is by sandblasting a reflective surface.
Both reflective and transmissive cases can be considered pseudo random.
Optical diffusers have household, industrial and scientific applications. The type of diffuser and how it is applied is all dependent on the desired output of the optical device in use.
With an optical diffuser's ability to create homogeneous distributions, this makes them highly sought after for illumination applications. They can commonly be found on commercial lighting fixtures, head lamps, projectors, and in microscopy when illuminating samples.
Mars Rover Perseverance
The Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals (SHERLOC) is mounted on the Mars Rover Perseverance. Located on the rover’s robotic arm, SHERLOC uses cameras, spectrometers, and a laser to search for signs of past microbial life by observing organics and minerals that have been altered by watery environments. Diffusers are used to give the laser beam a lambertian output when scanning organics and minerals.
With Perseverance being on Mars, it has to undergo very harsh conditions. As well, due to the rover being isolated it is impossible for engineers to make repairs if any equipment were to break or malfunction. This requires the use of strong, reliable, high performing optical equipment.This is why they turned to opsira’s optical diffusil diffuser.
opsira’s diffusil diffusers are lambertian diffusers made of a synthetic fused silica glass (99.999% SiO2). They are designed to create an almost perfect lambertian output over a wide range of wavelengths, with applications for transmission or reflection.