Subwavelength Post-Grating Optical Filter for Laser-Wavelength Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Integrated optical components are vulnerable to malfunctions and damage from high-energy laser radiation, particularly in applications like LIDAR and infrared facial recognition, due to conventional band-stop filters' inability to protect wavelengths close to the interfering range.
Innovation Solution
An optical filter with a periodic grating of posts, using dielectric or semiconductor materials, selectively reflects interfering wavelengths through quantum resonance, maintaining transparency to other wavelengths, and is integrated with anti-reflective layers to manage incident angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional band-stop filter is used to block interfering wavelengths, then protection from high-energy laser radiation is improved, but transparency to wavelengths close to the interfering range deteriorates
Solution Approach 1:
The patent changes the fundamental parameter of the filtering mechanism from conventional broad-band rejection to quantum resonance-based selective reflection. By using posts with characteristic dimensions smaller than the interfering wavelength and configuring them to exploit quantum resonance effects, the filter achieves narrowband rejection at the interfering wavelength while maintaining transparency to nearby wavelengths, thus resolving the contradiction between protection and transparency.
Solution Approach 2:
The patent applies local quality by creating a periodic grating structure where individual posts are strategically positioned and dimensioned to interact with specific wavelengths. The posts have characteristic dimensions (diameter and height) that are locally optimized to produce quantum resonance at the interfering wavelength, while the periodic arrangement creates a spatially distributed filtering effect that maintains overall transparency to other wavelengths.
2Measurement precision
If the characteristic dimensions of the periodic grating are reduced to achieve selectivity, then wavelength selectivity is improved, but manufacturing precision requirements worsen
Solution Approach 1:
The patent segments the filtering function into multiple discrete posts arranged in a periodic grating pattern. Instead of requiring a single complex structure with sub-wavelength precision, the segmentation into repetitive unit cells allows for more manageable manufacturing. Each post can be fabricated with standard precision, and the collective periodic arrangement produces the desired quantum resonance effect, thereby reducing individual manufacturing precision requirements while maintaining wavelength selectivity.
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 filter effectively protects optical components by selectively reflecting interfering wavelengths while allowing other wavelengths to pass unaltered, ensuring operational integrity in applications requiring proximity to the interfering wavelengths.
Implementation Method 1
the periodic grating of posts is configured to exploit a quantum resonance effect that produces a reflection of light specifically at the interfering wavelength
Implementation Method 2
the characteristic dimensions of the periodic grating of posts are configured to produce, selectively on light rays at the interfering wavelength, constructive light interference on one side of the periodic grating, and destructive light interference on the other side
Implementation Method 3
the characteristic dimensions of the periodic grating of posts are configured to selectively reflect light at the interfering wavelength on the periodic grating of posts
Data Source
AI summary
An optical filter includes a carrier layer made of a first material. A periodic grating of posts is disposed on the carrier layer in a periodic pattern configured by characteristic dimensions. The posts are made of a second material. A layer made of a third material encompasses the periodic grating of posts and covers the carrier layer. The third material has a refractive index that is different from a refractive index of the second material. Characteristic dimensions of the periodic grating of posts are smaller than an interfering wavelength and are configured to selectively reflect light at the interfering wavelength on the periodic grating of posts.