Nanophotonic Dispersion Array for Wide-Angle Compact Spectrometers
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Solution Overview
Problem
Existing spectrometers are bulky and have low angular tolerances, limiting their use on mobile devices, necessitating the development of a compact spectrometer with high angular tolerances for applications such as handheld devices.
Innovation Solution
A compact spectrometer design incorporating a dispersion array with nanostructures and a filter layer, capable of dispersing light into different wavelengths using a metasurface configuration, integrated with a smartphone camera for simultaneous imaging and spectroscopy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional dispersive elements (diffraction grating or prism) are used in spectrometers, then spectral dispersion capability is achieved, but the device becomes bulky and has low angular tolerances
Solution Approach 1:
The patent transforms the traditional bulk dispersive elements into metasurface structures with sub-wavelength thickness. By changing the physical state from volumetric (prism/grating) to planar (metasurface), the dispersion function is maintained while reducing the optical path length and device volume by orders of magnitude.
Solution Approach 2:
The patent replaces mechanical/optical dispersive elements (diffraction gratings, prisms) with a metasurface that achieves dispersion through sub-wavelength nanostructure geometry rather than traditional optical path manipulation. This substitution enables compact integration while maintaining spectral separation capability.
2Measurement precision
If traditional dispersive elements are used, then spectral dispersion is achieved, but angular tolerance remains low requiring precise alignment
Solution Approach 1:
The metasurface design operates in the sub-wavelength regime where the unit cell dimensions are smaller than the operating wavelength. This parameter change creates an effective medium that exhibits homogeneous optical response over a wide angular range, significantly improving angular tolerance compared to traditional dispersive elements.
Solution Approach 2:
The patent transitions from three-dimensional volumetric dispersive elements to two-dimensional planar metasurfaces. This dimensional reduction enables the incorporation of angular-insensitive dispersion mechanisms that are inherently more tolerant to incident angle variations.
3Volume of moving object
If metasurface configuration is used for light dispersion, then device compactness is improved, but manufacturing complexity increases
Solution Approach 1:
The metasurface is divided into repeating unit cells with identical or similar nanostructure patterns. This segmentation allows the complex metasurface to be fabricated using standard lithography techniques by defining periodic patterns, significantly reducing manufacturing complexity compared to arbitrary nanoscale structures.
Solution Approach 2:
The patent employs homogeneous or periodically varying nanostructure geometries across the metasurface. This homogeneity enables the use of conventional semiconductor fabrication processes and simplifies the lithography patterns required, making the metasurface manufacturable with existing technology.
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
Enables high-performance, ultra-compact spectrometers with large input angular tolerance, allowing for accurate spectroscopy and imaging in handheld devices without precise alignment, suitable for consumer use.
Implementation Method 1
scattering incident light through a scattering layer to create scattered light
Implementation Method 2
dispersing a subset of the scattered light through a dispersion layer to create dispersed light
Data Source
AI summary
Optical spectrometers may be used to determine the spectral components of electromagnetic waves. Spectrometers may be large, bulky devices and may require waves to enter at a nearly direct angle of incidence in order to record a measurement. What is disclosed is an ultra-compact spectrometer with nanophotonic components as light dispersion technology. Nanophotonic components may contain metasurfaces and Bragg filters. Each metasurface may contain light scattering nanostructures that may be randomized to create a large input angle, and the Bragg filter may result in the light dispersion independent of the input angle. The spectrometer may be capable of handling about 200 nm bandwidth. The ultra-compact spectrometer may be able to read image data in the visible (400-600 nm) and to read spectral data in the near-infrared (700-900 nm) wavelength range. The surface area of the spectrometer may be about 1 mm2, allowing it to fit on mobile devices.