Spectral interference in multiplexed volume Bragg gratings: theoretical calculations and experimental verification

Area of Science:

• Optics and Photonics
• Holographic Optical Elements
• Diffractive Optics

Background:

• Multiplexed volume Bragg gratings (VBGs) are crucial components in various spectral systems.
• Combining multiple gratings into a single holographic optical element (HOE) can lead to reduced efficiency and unwanted wave generation.
• Efficient design methods are needed to analyze and mitigate these side effects in HOEs.

Purpose of the Study:

• To present a flexible and efficient matrix-based algorithm for analyzing multiplexed grating HOEs.
• To accurately determine diffraction efficiencies of coupled waves within these complex optical elements.
• To validate the proposed algorithm through experimental verification.

Main Methods:

• Development of a novel matrix-based algorithm for analyzing coupled wave diffraction.
• Implementation of the algorithm to predict diffraction efficiencies in multiplexed HOEs.
• Experimental validation using spectrally multiplexed gratings fabricated in dichromated gelatin.

Main Results:

• The matrix-based algorithm accurately predicts diffraction efficiencies for significant coupled waves.
• Experimental results confirm the algorithm's predictions for multiplexed gratings.
• The method effectively accounts for efficiency losses and spurious wave generation in HOEs.

Conclusions:

• The presented matrix-based algorithm provides a robust tool for designing multiplexed grating HOEs.
• This approach enables efficient analysis and optimization of spectral systems utilizing HOEs.
• Experimental validation confirms the reliability and accuracy of the developed algorithm.