High-resolution laser lithography system based on two-dimensional acousto-optic deflection.

Area of Science:

• Photonics and Optical Engineering
• Nanofabrication
• Materials Science

Background:

• Advanced integrated optics require high-resolution patterning techniques.
• Existing lithography methods can be slow or limited in feature size for complex structures.

Purpose of the Study:

• To develop a high-resolution, compact laser lithography system for fast prototyping of integrated optics.
• To enable precise fabrication of microring resonators and photonic crystal structures.

Main Methods:

• Utilized a 375 nm continuous wave diode laser and a 2D acousto-optical deflector for beam steering and intensity control.
• Employed a three-axis (xyz) stage for precise sample positioning.
• Achieved sub-200 nm feature resolution using a high numerical aperture (1.40) objective lens.
• Implemented a two-step lithography process to create small gaps between structures.

Main Results:

• Demonstrated structure widths of approximately 200 nm.
• Achieved gaps as small as 150 nm between adjacent structures.
• Obtained a write-field of up to 200x200 µm².
• Produced superior photoresist masks for microring resonators with coupling ports.

Conclusions:

• The developed laser lithography system is effective for rapid, high-resolution prototyping of complex integrated optical devices.
• The system's capabilities in achieving small feature sizes and gaps are crucial for advanced photonic applications.