Interactive Point Spread Function Simulation with Diffraction and Interference Effects

Interactive simulation of point spread functions is an invaluable tool for evaluating optical designs. We present an interactive method for simulating the point spread function for designs that require diffraction and interference effects. These effects occure when the design contains apertures whose size approaches the wavelength of light, typically in the form of gratings or masks. Traditional ray-based techniques are not suitable here, whereas wave-based methods are not immediately amenable to an efficient implementation due to their complexity. We propose a method based on the Wigner Distribution function. This function models wave optics at gratings, but does so in a ray-based framework. This enables us to simulate diffraction and interference effects efficiently, even for multiple gratings. The resulting computation is in the order of a fraction of a second, thereby enabling the user to interactively manipulate the optical configuration or the projection plane. The proposed method can be scaled down in precision in order to achieve real-time performance.