Differentiable freeform lens design for irradiance tailoring on tilted target plane

Here focus on freeform lens design for irradiance tailoring on tilted target planes based on differentiable ray tracing. Leveraging the computational graph, we develop a differentiable Monte Carlo ray tracing framework featuring a 3D coordinate rotation operator. The forward calculation within this framework can simulate the irradiance distribution on a tilted target plane generated by a freeform lens, facilitating the assessment of deviations from the desired irradiance distribution. The back-propagation efficiently acquires surface parameter gradients for optimization through the Adam optimizer. The design example demonstrates that the proposed method can effectively generate a high-quality uniform irradiance distribution on a tilted receiver.