Mid-infrared cavity resonator integrated grating filters

Area of Science:

• Optics and Photonics
• Materials Science

Background:

• Mid-infrared (MIR) spectral range is crucial for various applications including spectroscopy, sensing, and telecommunications.
• Developing efficient and tunable filters for the MIR region remains a significant challenge.

Purpose of the Study:

• To design and fabricate Cavity Resonator Grating Filters (CRIGFs) for operation in the Mid-Infrared (MIR) spectral range.
• To investigate the optical properties, specifically reflectivity and bandwidth, of these novel filters.

Main Methods:

• CRIGFs were fabricated using the GaAs/AlGaAs material system.
• Optical characterization was performed to measure reflectivity peaks and spectral width.

Main Results:

• Narrow-band resonant reflectivity peaks were observed around 2200 cm^-1 (4.6 µm).
• The filters exhibit a peak reflectivity of 30% for TE-polarized light.
• A narrow full width at half maximum (FWHM) of 4 cm^-1 was achieved.

Conclusions:

• GaAs/AlGaAs CRIGFs are a promising technology for MIR filtering applications.
• The demonstrated performance suggests potential for covering the entire 1-12 µm spectral range.
• These filters offer a pathway to enhanced performance in MIR optical systems.