Reduced wavelength-dependent quarter-wave plate fabricated by a multilayered subwavelength structure

Area of Science:

• Optics and Photonics
• Materials Science
• Nanotechnology

Background:

• Quarter-wave plates (QWPs) are crucial optical components for controlling light polarization.
• Traditional QWPs often exhibit wavelength dependency, limiting their performance in broadband applications.
• Developing wavelength-independent QWPs is essential for advanced optical systems.

Purpose of the Study:

• To develop a novel fabrication method for a reduced wavelength-dependent quarter-wave plate (QWP).
• To utilize form birefringence in multilayered subwavelength structures for enhanced optical properties.
• To achieve a QWP with suppressed phase retardance variation across a spectral region.

Main Methods:

• Fabrication of a multilayered subwavelength structure by depositing a high-refractive-index thin film on a low-refractive-index substrate.
• Utilizing mass replication technology for creating a shallow surface structure on the substrate.
• Forming a high-refractive-index subwavelength grating (Zn2SnO4) via sputtering and leveraging deep, narrow grooves to control form birefringence and its dispersion.

Main Results:

• A novel QWP was successfully fabricated using a multilayered subwavelength structure.
• The fabricated QWP demonstrated reduced wavelength dependency in phase retardance.
• Phase retardance values of 89 degrees at 633 nm and 79 degrees at 785 nm were achieved, indicating limited spectral dispersion.

Conclusions:

• The developed fabrication method effectively produces reduced wavelength-dependent QWPs.
• Form birefringence in multilayered subwavelength structures offers a viable approach for broadband polarization control.
• This technology holds potential for applications requiring stable optical performance across different wavelengths.