Sensitivity analysis and optimization method for the fabrication of one-dimensional beam-splitting phase gratings

Area of Science:

• Optics and Photonics
• Diffractive Optics
• Nanofabrication

Background:

• Phase gratings are crucial optical components for beam splitting.
• Fabrication errors can significantly impact the performance of diffractive optical elements.
• Existing designs often prioritize efficiency over robustness to errors.

Purpose of the Study:

• To develop a novel method for designing one-dimensional beam-splitting phase gratings.
• To minimize sensitivity to fabrication errors in phase grating design.
• To enhance the reliability of beam-splitting devices in practical applications.

Main Methods:

• A new optimization technique was employed to design the grating phase function.
• The method minimizes the integrated variance of output beam energies across a range of fabrication errors.
• Three 1x9 beam-splitting gratings were designed and fabricated using gray-scale photolithography.

Main Results:

• Two optimized gratings exhibited significantly lower sensitivity to fabrication errors.
• The standard deviation of output beam energies was 2.3 and 3.4 times lower in optimized gratings compared to an optimal efficiency grating.
• Fabrication via gray-scale photolithography was successful for the designed gratings.

Conclusions:

• The proposed design method effectively reduces the impact of fabrication errors on beam-splitting phase gratings.
• Optimized gratings offer improved stability and reliability for beam manipulation applications.
• This approach is valuable for creating robust diffractive optical elements.