Guided-mode resonance-based bandpass filter operating at full conical mounting

Area of Science:

• Optics and Photonics
• Materials Science

Background:

• Guided-mode resonance (GMR) structures offer potential for highly selective optical filters.
• Achieving narrow bandpass characteristics with large angles of incidence remains a challenge.

Purpose of the Study:

• To propose and analyze a cost-effective narrow bandpass filter utilizing a GMR structure.
• To investigate the performance of the GMR filter under full conical mounting and large angles of incidence.

Main Methods:

• Utilizing a GMR structure with two additional designed layers to manage angle of incidence (AOI).
• Employing a matrix method for n-layer waveguide structures to identify modal characteristics.
• Analyzing the transmission spectrum in the visible wavelength range.

Main Results:

• The filter exhibits three transmission peaks: two GMR peaks and one thin-film interference peak.
• Two GMR peaks with bandwidths of ~1 nm and ~0.5 nm correspond to fundamental TE and TM modes, respectively.
• Modulating grating depth allows control over GMR peak positions relative to the interference peak.

Conclusions:

• The proposed GMR structure provides a cost-effective solution for narrow bandpass filtering.
• The filter demonstrates effective separation of TE and TM modes with high spectral resolution.
• Tunability of GMR peaks offers design flexibility for specific optical applications.