Holographic fabrication of an arrayed one-axis scale grating for a two-probe optical linear encoder

Area of Science:

• Optics and Photonics
• Metrology and Measurement Science
• Materials Science and Engineering

Background:

• Precision measurement systems often rely on optical encoders for accurate linear displacement sensing.
• Traditional fabrication of large-scale gratings can be complex and costly, limiting their widespread application.
• Existing methods may require stringent control over grating parameters, increasing manufacturing challenges.

Purpose of the Study:

• To present a novel method for fabricating arrayed one-axis scale gratings for two-probe optical linear encoders.
• To demonstrate the utility of a dual-beam interference lithography (IL) system with a compact diode laser source.
• To enable the creation of large-width gratings with small line spacing through a simplified and robust process.

Main Methods:

• Utilizing a dual-beam interference lithography (IL) system.
• Employing a multiple-exposure stitching technique to form arrayed scale gratings.
• Integrating the fabricated gratings with a newly developed two-probe optical encoder.

Main Results:

• Successfully fabricated arrayed scale gratings with small line spacing over a large width.
• Demonstrated seamless numerical connection of measurement results from the two-probe encoder.
• Validated a simplified and robust fabrication process by eliminating the need for gap width and grating phase control.
• Confirmed the feasibility of the technology through experimental validation.

Conclusions:

• The proposed interference lithography (IL) based multiple-exposure stitching method offers a flexible and cost-effective approach for fabricating large-scale gratings.
• This technique simplifies the manufacturing process for optical encoders, enhancing their practicality in precision measurement.
• The developed method holds significant potential for advancing various precision measurement applications.