Ultraviolet polarizer with a Ge subwavelength grating

Area of Science:

• Optics and Photonics
• Materials Science

Background:

• High extinction ratio (ER) polarizers are crucial for optical systems.
• Existing polarizers often require high structural aspect ratios, increasing fabrication complexity.

Purpose of the Study:

• To develop a novel polarizer with a high ER in the ultraviolet (UV) wavelength region.
• To investigate the use of germanium subwavelength gratings (Ge-SWG) for polarizer applications.
• To achieve high ER performance without a high structural aspect ratio.

Main Methods:

• Numerical prediction utilizing an eigenmode within the Ge-SWG structure.
• Fabrication of the proposed Ge-SWG using lithography techniques.

Main Results:

• A high ER was numerically predicted for the Ge-SWG.
• Experimentally achieved an ER of 17.4 dB at a wavelength of 360 nm.
• The developed Ge-SWG exhibited a very low structural aspect ratio of 1.67.

Conclusions:

• Germanium subwavelength gratings are effective for creating high ER polarizers in the UV region.
• The developed Ge-SWG offers a low-aspect-ratio solution for high-performance UV polarization.
• This technology has potential for advanced optical device applications.