Laser Processing of Poly(methyl methacrylate) Lambertian Diffusers
NAVAL RESEARCH LAB WASHINGTON DC FUNCTIONAL MATERIALS SECTION
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Matrix-assisted pulsed laser deposition was used to deposit polymethyl methacrylate on silicon wafers and sodium silicate glass slides for the purpose of making optical diffusers. After deposition, the reflectance of the coated substrates was measured as a function of scattering angle. We found that the angular dependence of the reflectance could be described as the sum of two functions. First, a Gaussian describes the specular reflection of the underlying substrate that has been broadened by passage through the film. Second, a cosine function describes the reflectance contribution from the film itself. We found that by increasing the thickness of the deposited film that we could eliminate the specular reflection to obtain Lambertian diffusers. Since we can control the surface roughness by adjusting the ratio of the two matrices in laser-processing, this deposition technique offers the possibility of producing a wide range of diffusers of different types.
- Industrial Chemistry and Chemical Processing
- Lasers and Masers
- Ceramics, Refractories and Glass
- Numerical Mathematics