Simulation of Sinusoidal Amplitude Transmission Gratings Commonly Used in Optical Systems

In optical systems, sinusoidal amplitude transmission gratings are common optical components characterized by sinusoidal transmittance variations that effectively modulate the amplitude of incident light. Through simulation techniques, we can deeply analyze their diffraction properties and observe light intensity distribution patterns. The simulation typically employs scalar diffraction theory, where the grating's transmission function can be represented as a sinusoidal variation along the x-direction. In code implementation, this is often achieved using Fourier transform algorithms to model light propagation. When parallel light incidents on the grating, specific diffraction patterns form in the far field or focal plane. Simulation results demonstrate that the diffracted light field primarily consists of 0th-order, +1st-order, and -1st-order diffraction spots, which is determined by the periodic structure of sinusoidal gratings. The programming approach typically involves calculating the Fourier transform of the grating function to obtain the diffraction pattern distribution. The light intensity curve along the x-axis provides a clear visualization of spatial diffraction energy distribution. The 0th-order diffraction spot corresponds to undeflected direct light, while the ±1st-order spots exhibit symmetrical intensity distributions whose strength relates to the grating's modulation depth. By adjusting spatial frequency or amplitude modulation parameters in the simulation code, diffraction efficiency can be further optimized. This optimization process can be implemented through parameter scanning algorithms that systematically vary grating parameters. This simulation methodology not only applies to sinusoidal grating analysis but can also be extended to the design and optimization of other complex grating structures, providing crucial references for optical system performance evaluation. The code framework typically includes modular functions for grating parameter definition, propagation calculation, and result visualization, making it adaptable for various grating types.