Low resolution fabrication of highly precise diffractive optics by near index matching

Diffractive optical elements (DOEs) are essential in optics and photonics, offering compact solutions for complex wavefront shaping. Despite their potential, the widespread adoption of DOEs remains constrained by the high costs and complexities of current fabrication techniques. This study introduces a simple, cost-effective method for fabricating high-performance, solid DOEs by conjugating two nearly index-matched transparent materials. This approach leverages commercially available additive manufacturing (AM) to produce templates at a resolution of tens of micrometers, enabling substantial scaling in the axial dimension, dramatically simplifying fabrication. The method's versatility is demonstrated through the production of microlens arrays, vortex plates, and phase masks for three-dimensional localization microscopy. Additionally, it facilitates the fabrication of highly complex elements, such as high-order spiral phase plates and spectrum-encoding phase masks, significantly expanding the accessibility and applicability of DOEs.