Efficient simulation of surface scattering in symmetry-free optical systems

Area of Science:

• Optical Engineering
• Computational Physics

Background:

• Monte Carlo methods are standard for simulating scattering from optical surfaces using the bidirectional scattering distribution function (BSDF).
• These methods involve random ray sampling, leading to significant computational time and potential statistical noise.
• Existing deterministic models are often limited by the paraxial approximation, affecting accuracy.

Purpose of the Study:

• To develop a faster and more accurate simulation method for scattering from optical surfaces.
• To overcome the limitations of traditional Monte Carlo methods and paraxial approximations in stray light analysis.
• To enable the modeling of complex optical surfaces, including freeform geometries.

Main Methods:

• A quasi-analytical phase space model is proposed, tracing few rays to define illumination and acceptance areas.
• The model couples spatial and angular domains simultaneously within the phase space.
• Optical surfaces are discretized into subareas to accommodate arbitrary geometries and space-variant BSDFs.

Main Results:

• The phase space model significantly accelerates simulation times by avoiding random sampling.
• The absence of random sampling eliminates statistical noise from the results.
• The use of real raytracing removes the paraxial approximation, enhancing accuracy for stray light analysis.

Conclusions:

• The quasi-analytical phase space model offers a substantial improvement in speed and accuracy for optical surface scattering simulations.
• This approach effectively handles complex, freeform optical surfaces and space-variant scattering properties.
• It provides a powerful alternative to Monte Carlo methods for stray light analysis in optical design.