Abstract
When combined with soft nanoimprinting, grayscale lithography (GS) offers a powerful and low-cost alternative to traditional etch-based methods for high-quality diffractive optics. Unlike etching, which faces challenges in surface roughness, aspect ratio control, and multilevel patterning, GS enables continuous relief profiles in a single exposure step, transferred with high fidelity through nanoimprinting. We demonstrate this approach by fabricating various diffractive optical elements (DOEs) for three applications. First, a 10π harmonic Fresnel lens shows advanced chromatic aberration correction compared to the traditional 2π Fresnel lens. Second, a high-quality computer-generated holography produces fine spatial features. Third, a reflective DOE exhibits a designed bidirectional reflectance distribution function. These results confirm that the combined GS and nanoimprint process not only overcomes key drawbacks of etching but also expands the design space for advanced diffractive optics in imaging, augmented reality, and compact optical systems.