Optical Filter With Ring-Shaped Nanostructures For Compact Spectrometers
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Solution Overview
Problem
Existing optical filters with sub-wavelength structures face challenges in setting a desired resonant wavelength in ultra-compact sizes, particularly when increasing the number of stacked layers is necessary for higher reflectivity, and they often exhibit polarization and angle-dependent spectral characteristics.
Innovation Solution
The optical filter design incorporates periodically arranged ring-shaped or disc-shaped nanostructures with specific dimensions and refractive indices for the first and second reflectors, allowing for precise control of the transmission wavelength and eliminating polarization and angle dependencies through a Fabry-Perot resonator configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of stacked layers is increased to achieve higher reflectivity, then the reflectivity is improved, but the device size increases and it becomes difficult to achieve ultra-compact dimensions
Solution Approach 1:
The patent changes the geometric parameters of the nanostructures (size, shape, spacing) and material parameters (refractive index) to achieve high reflectivity with fewer layers. By optimizing these parameters, the device attains the desired optical performance in a more compact form factor.
Solution Approach 2:
The patent employs composite structures combining multiple materials with different refractive indexes arranged in specific patterns. This composite approach enables enhanced optical control and high reflectivity without requiring a large number of stacked layers, thus reducing overall device size.
2Volume of moving object
If conventional sub-wavelength structures are used, then miniaturization is achieved, but polarization and angle-dependent spectral characteristics are introduced
Solution Approach 1:
The patent introduces asymmetric unit cell structures that are optimized to provide polarization-insensitive and angle-insensitive optical responses. The asymmetric geometry is specifically designed to maintain consistent spectral characteristics across different incident angles and polarization states, eliminating the limitations of conventional symmetric sub-wavelength structures.
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
This design enables high reflectivity and narrow bandwidth transmission with a high degree of freedom in wavelength selection, achieving excellent spectral characteristics without polarization or angle dependency, suitable for use in compact spectrometers and optical filters.
Implementation Method 1
allowing for precise control of the transmission wavelength and eliminating polarization and angle dependencies through a Fabry-Perot resonator configuration
Implementation Method 2
The transmission wavelength of the incident light may be determined based on at least one of respective refractive indexes of the plurality of first structures and the plurality of second structures
Implementation Method 3
a resonant structure having a specific resonant wavelength may be implemented by arranging two reflectors spaced apart by a certain distance from each other
Data Source
AI summary
An optical filter, a spectrometer including the optical filter, and an electronic apparatus including the optical filter are disclosed. The optical filter includes a first reflector including a plurality of first structures that are periodically two-dimensionally arranged, each of the first structures having a ring shape, and a second reflector spaced apart from the first reflector and including a plurality of second structures that are periodically two-dimensionally arranged.