Macroporous Silicon Band-Pass Filter for Infrared Sideband Blocking
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Solution Overview
Problem
Existing optical filters using macroporous silicon for infrared light filtering and emitting fail to effectively block or remove sidebands, limiting their market introduction due to uncontrolled transmission and reflection issues.
Innovation Solution
A photonic crystal structure based on macroporous silicon with a resonator block, high-pass and low-pass blocks, and antireflective layers, designed to provide a resonance peak in the center of a non-transmitting bandgap, using electrochemical etching to control light transmission and reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If macroporous silicon is used for infrared light filtering, then the filter can be manufactured with controlled porosity and periodic structure, but sidebands are generated due to multiple resonances that limit market introduction
Solution Approach 1:
The filter structure is divided into multiple periodicity groups with different periods (first periodicity group with period Λ1, second periodicity group with period Λ2). Each group targets different wavelength ranges, allowing the first group to block sidebands while the second group maintains the main transmission band, thus eliminating harmful sidebands without sacrificing manufacturing precision
Solution Approach 2:
Different regions of the filter are given different porosity characteristics. The first periodicity group has porosity optimized for blocking sidebands, while the second periodicity group has porosity optimized for transmitting the main infrared band. This local differentiation allows each region to perform its specific function effectively
2Length of stationary object
If multiple periodicity groups are concatenated to increase bandgap, then the bandgap width increases to cover LED emission spectrum, but transmission of resonance peak decays due to higher reflection in resonator groups
Solution Approach 1:
The patent changes the period parameter between different periodicity groups. The first periodicity group uses period Λ1 for sideband blocking, while the second periodicity group uses period Λ2 for main band transmission. By optimizing these parameters, the patent achieves wide bandgap coverage while maintaining high transmission intensity at the resonance peak, avoiding the decay problem
3Measurement precision
If resonator block is used to provide resonance peak in bandgap, then selective transmission is achieved, but sidebands occur in both bands of the bandgap that remain unblocked
Solution Approach 1:
The filtering function is segmented between two periodicity groups. The first periodicity group specifically targets and blocks sidebands, while the second periodicity group maintains the resonance peak transmission. This segmentation allows wavelength selectivity to be achieved without the harmful sideband effect
Solution Approach 2:
The first periodicity group acts as an intermediary element between the resonator block and the external environment. It mediates the optical field by blocking sidebands before they can propagate, while allowing the main resonance peak to pass through the second periodicity group
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves high emissivity and selectivity in infrared light filtering by blocking sidebands, enhancing light interaction and absorption, thereby improving filter performance and market applicability.
Implementation Method 1
a resonator block, comprising at least two periodicity groups between which there is a resonant cavity, wherein the resonant cavity is adapted to provide a resonance peak in the center of a non-transmitting frequency band, or bandgap, of the resonator block
Implementation Method 2
the resonant cavity is adapted to provide a resonance peak in the center of a non-transmitting frequency band
Implementation Method 3
The filter is obtained using macroporous silicon technology, manufactured by means of the electrochemical etching process
Data Source
AI summary
The present invention proposes an optical band-pass filter with blocked sidebands. The filter comprises a photonic crystal structure based on macroporous silicon having a series of pores defined in the structure. The photonic crystal structure includes a resonator block (BR), comprising at least two periodicity groups (GR1, GR2) between which there is a resonant cavity (CR), wherein the resonant cavity (CR) is adapted to provide a resonance peak in the center of a non-transmitting frequency band of the resonator block (BR); and at least one of a high-pass block (BPA), adapted to block wavelengths below said non-transmitting frequency band; or a low-pass block (BPB), adapted to block wavelengths above said non-transmitting frequency band.