Photolithographic fabrication method of computer-generated holographic interferograms

Area of Science:

• Optics
• Optical Engineering
• Materials Science

Background:

• Diffractive optical elements (DOEs) are crucial for manipulating light.
• Electron-beam lithography offers high resolution but is costly and slow.
• Conventional photolithography presents a potentially more accessible fabrication method.

Purpose of the Study:

• To evaluate the feasibility of using conventional photolithography for high-quality interferogram-type DOEs.
• To compare photolithography results with those from electron-beam lithography.
• To analyze the impact of rectangle quantization on DOE performance.

Main Methods:

• Fabrication of binary phase holographic interferograms using photolithography.
• Approximation of phase transfer function fringes with rectangles at submicron accuracy.
• Numerical and experimental analysis of rectangle quantization effects using diffraction patterns.
• Comparison of resolution and diffraction efficiency with theoretical values.

Main Results:

• High-quality interferogram-type DOEs were successfully fabricated using photolithography.
• The performance of photolithographically fabricated DOEs approached that of electron-beam lithography.
• Analysis confirmed that rectangle quantization effects were well-managed.
• The best holograms achieved resolution and diffraction efficiency close to theoretical maximums.

Conclusions:

• Conventional photolithography is a viable and effective technique for producing high-quality diffractive optical elements.
• Photolithography offers a competitive alternative to electron-beam lithography for DOE fabrication.
• The findings support the use of photolithography for advanced optical applications requiring precise diffractive structures.