MEMS Hadamard Spectrometer Echelle Grating Wavelength Range
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current MEMS based Hadamard spectrometers have limited wavelength resolution and range, restricted to one octave, making them inadequate for varying applications.
Innovation Solution
Incorporating a collimating element, cross-dispersing element, echelle gratings, and a spatial light modulator to enhance wavelength resolution and range beyond one octave, utilizing commercially available MEMS chips and a DLP mirror array.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single order diffraction grating is used in a MEMS-based Hadamard spectrometer, then the device can be manufactured with current MEMS chip capabilities, but the wavelength range is limited to one octave
Solution Approach 1:
The spectrometer divides the wavelength detection into multiple spectral orders using an echelle grating. Each order covers a specific wavelength range, and the cross-dispersing element separates these orders spatially. This segmentation allows the system to detect a wavelength range exceeding one octave (900-2500 nm) while using standard MEMS chip capabilities, as each individual order can be handled by conventional MEMS actuators.
Solution Approach 2:
The patent introduces a second dispersion dimension by adding a cross-dispersing element perpendicular to the echelle grating's dispersion direction. This creates a two-dimensional spectral mapping where one dimension separates wavelengths and the other separates diffraction orders. This dimensional approach enables extended wavelength range detection without requiring a single complex grating, thereby managing device complexity while achieving adaptability across 900-2500 nm.
2Measurement precision
If the MEMS chip capability is used to determine wavelength resolution, then the device can be manufactured with available technology, but the resolution is limited
Solution Approach 1:
The echelle grating divides the spectrum into multiple high-resolution orders, with each order providing fine wavelength discrimination. The cross-dispersing element further segments these orders spatially, allowing the detector to resolve wavelengths with 0.5 nm pixel resolution across the 900-2500 nm range. This segmented approach achieves high measurement precision while using commercially available MEMS chips that would be insufficient for a single high-resolution grating.
Solution Approach 2:
The cross-dispersing element acts as an intermediary between the echelle grating and the detector. It separates the overlapping spectral orders produced by the echelle grating into distinct spatial regions, enabling the detector to resolve individual wavelengths with high precision. This intermediary component allows the system to achieve 0.5 nm resolution without requiring excessively complex MEMS chip designs, as the cross-disperser handles the order separation function.
3Ease of manufacture
If commercially available MEMS chips and DLP mirror array are used, then the device can be manufactured with existing technology, but the wavelength range and resolution must be compromised
Solution Approach 1:
The patent employs commercially available MEMS chips and DLP mirror arrays to perform multiple functions: wavelength modulation, spectral encoding, and detection. These universal components are used in a Hadamard transform spectroscopy configuration where they achieve both extended wavelength range (900-2500 nm) and high resolution (0.5 nm) simultaneously. The multi-functionality of these off-the-shelf components eliminates the need for custom high-end gratings while maintaining superior measurement precision through computational spectroscopy methods.
Solution Approach 2:
The system achieves extended wavelength range and high resolution by changing the operational parameters of commercially available MEMS components. The echelle grating is configured to operate in multiple diffraction orders, and the cross-dispersing element is positioned to optimize spatial separation. These parameter changes allow standard MEMS chips to achieve 0.5 nm resolution across 900-2500 nm, transforming limited components into a high-performance spectrometer through optimized configuration rather than component upgrades.
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 provides improved wavelength resolution and range, enhancing signal-to-noise ratio and enabling detection from 900 nm to 2500 nm with 0.5 nm pixel resolution, suitable for a wide sensitivity range and adaptable for different applications.
Implementation Method 1
a collimating element configured for collimating a beam of light into a first one of a cross-dispersing element and an echelle grating
Implementation Method 2
an echelle grating in optical communication with the cross-dispersing element
Implementation Method 3
a focusing element for receiving the light from a second one of the cross-dispersing element and the echelle grating and focusing wavelengths of the light onto a spatial light modulator
Implementation Method 4
a MEMS array adapted to be electrostatically actuated by a controller to control a diffraction of the light
Data Source
AI summary
A spectrometer includes: a collimating element configured for collimating a beam of light into a first one of a cross-dispersing element and an echelle grating, the grating in optical communication with the cross-dispersing element; a focusing element for receiving the light from a second one of the cross-dispersing element and the echelle grating and focusing wavelengths of the light onto a spatial light modulator; the spatial light modulator configured for selectively directing the wavelengths onto a detector for detection. A method of use and the method of fabrication are provided.