G-Fresnel Diffractive Element for Compact Spectrometer Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional optical spectrometers are bulky and costly due to the use of discrete optical components, necessitating a compact and cost-effective solution that integrates the functions of high-numerical-aperture lenses with diffraction gratings.
Innovation Solution
The development of a diffractive optical element, referred to as a G-Fresnel device, which combines the properties of Fresnel lenses and diffraction gratings, fabricated using polydimethylsiloxane (PDMS) soft lithography, allowing for a compact and low-cost spectrometer design with dual focusing and dispersing capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If discrete optical components (collimating mirrors, collecting mirrors, diffraction grating) are used in conventional spectrometers, then the spectrometer can achieve proper optical functionality, but the device becomes bulky and costly
Solution Approach 1:
The patent combines multiple discrete optical components (collimating mirror, collecting mirror, and diffraction grating) into a single integrated diffractive optical element. This element simultaneously performs collimation, dispersion, and focusing functions that were previously requiring separate components, thereby reducing device complexity while maintaining optical functionality
Solution Approach 2:
The diffractive optical element is designed to perform multiple optical functions simultaneously: it acts as a collimating element, a diffraction grating, and a focusing element all in one component. This multi-functionality eliminates the need for multiple discrete components and reduces the overall spectrometer size
2Ease of operation
If conventional lenses or mirrors are used, then the spectrometer can achieve proper focusing, but the f-number is large resulting in a bulkier design
Solution Approach 1:
The patent changes the optical parameters by using a diffractive optical element with specific diffraction grating patterns that enable the system to achieve a smaller f-number. The diffractive structure allows for more aggressive light bending and focusing, reducing the focal length and enabling a more compact spectrometer design while maintaining proper focusing capability
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 G-Fresnel device achieves a smaller f-number and enables the creation of compact, cost-effective spectrometers with potential applications in various fields, including portable electronics, astrophysics, and biomedical diagnostics, while maintaining high spectral resolution.
Implementation Method 1
diffractive optical element that integrates the functions of high-numerical-aperture lenses (possibly Fresnel lenses) with diffraction gratings
Implementation Method 2
Fresnel lenses with diffraction gratings
Implementation Method 3
high-numerical-aperture lenses (possibly Fresnel lenses)
Data Source
AI summary
Embodiments of the invention provide a device called a “G-Fresnel” device that performs the functions of both a linear grating and a Fresnel lens. We have fabricated the G-Fresnel device by using PDMS based soft lithography. Three-dimensional surface profilometry has been performed to examine the device quality. We have also conducted optical characterizations to confirm its dual focusing and dispersing properties. The G-Fresnel device can be useful for the development of miniature optical spectrometers as well as emerging optofluidic applications. Embodiments of compact spectrometers using diffractive optical elements are also provided. Theoretical simulation shows that a spectral resolution of approximately 1 nm can be potentially achieved with a millimeter-sized G-Fresnel. A proof-of-concept G-Fresnel-based spectrometer with subnanometer spectral resolution is experimentally demonstrated.