Materials with on-demand refractive indices in the terahertz range

Area of Science:

• Materials Science
• Optics
• Terahertz Technology

Background:

• Developing materials with specific optical properties is crucial for advanced photonic devices.
• Birefringent materials are essential for controlling light polarization and enabling novel optical functionalities.

Purpose of the Study:

• To demonstrate the fabrication of materials with tunable refractive indices and high birefringence in the terahertz range.
• To utilize these materials as building blocks for photonic crystals with specific spectral characteristics.

Main Methods:

• Etching patterns into a dielectric substrate (silicon wafers) with controlled filling factors.
• Utilizing deep inductive plasma etching to achieve precise microstructures.
• Characterizing the birefringence and optical properties of the fabricated materials.

Main Results:

• Achieved a high birefringence of 1.2 in an 80 micrometer thick silicon layer.
• Demonstrated the ability to tune refractive indices by controlling pattern filling factors.
• Fabricated photonic crystals exhibiting sharp defect mode peaks in transmittance spectra.

Conclusions:

• Deep inductive plasma etching of silicon is a viable method for creating highly birefringent terahertz materials.
• The fabricated materials serve as effective building blocks for terahertz photonic crystals.
• This approach offers a pathway to engineer bespoke optical properties for terahertz applications.