Design and fabrication of narrow-frequency sharp angular filters

Area of Science:

• Photonics
• Materials Science
• Optical Engineering

Background:

• One-dimensional defective photonic crystals exhibit unique optical properties.
• Understanding defect mode behavior is crucial for optical filter design.
• Photonic crystals offer tunable frequency and angular responses.

Purpose of the Study:

• To theoretically deduce frequency variations of defect modes in 1D defective photonic crystals.
• To investigate the dependence of defect mode frequency on incident angle.
• To design and fabricate filters with narrow frequency passbands and sharp angular breadths.

Main Methods:

• Theoretical deduction of defect mode frequency variations.
• Design of filters based on integral quarter-wavelength layers for defect mode and periodic structure.
• Fabrication using standard coating machines.

Main Results:

• The study discusses the theoretical basis for frequency variations in defect modes.
• Filters were designed exhibiting narrow frequency passbands and sharp angular pass breadths.
• The designed filters operate in visible and near-infrared wavebands.

Conclusions:

• The theoretical framework explains defect mode behavior in 1D photonic crystals.
• Novel filters with dual narrow frequency and angular passbands were successfully designed.
• Fabrication using common coating machines demonstrates practical applicability.