Multi-Wavelength Raman Sensor Module for Handheld Spectroscopy
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Solution Overview
Problem
Raman spectroscopy devices are bulky and not suitable for handheld applications due to limited emitter and detector technologies, especially in the long wavelength range where skin constituents like Urea, Lactate, and Glucose have strong optical fingerprints, and skin absorption limits penetration depth.
Innovation Solution
A sensor module combining multiple light emitters with a dispersive element and a single photon detector, utilizing a closed loop control scheme and miniaturized components like arrayed waveguide gratings, to extend the spectral range and enable accurate measurements in a compact form factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single dispersive element is used to cover the long wavelength range (8-12 μm), then the spectral range is extended, but the device size increases and cannot be miniaturized for handheld applications
Solution Approach 1:
The spectral range is segmented into multiple bands, each covered by a dedicated light emitter (e.g., 830 nm, 850 nm, 880 nm lasers). This allows each dispersive element to be smaller and optimized for its specific wavelength range, while the overall system achieves broad spectral coverage through multiple segmented emitters working in parallel
Solution Approach 2:
Multiple light emitters at different wavelengths are combined to create a universal detection system that can measure various skin constituents (glucose, urea, lactate) across different spectral ranges. The same compact sensor module design can serve multiple analytical functions by simply changing which emitters are activated
2Measurement precision
If multiple light emitters are used to extend spectral range, then the measurement accuracy improves, but the device complexity increases
Solution Approach 1:
Multiple light emitters and their corresponding dispersive elements are merged into a single integrated sensor module that can be miniaturized for handheld devices. The module combines all necessary components (emitters, detectors, dispersion elements) in one compact unit, reducing overall system complexity while maintaining high measurement precision through multi-wavelength capability
Solution Approach 2:
The system incorporates feedback mechanisms where the detected Raman signals are processed and compared against reference values to improve measurement accuracy. The multi-wavelength emitters allow for feedback-based correction of spectral distortions and enhancement of signal-to-noise ratio, thereby improving precision without proportionally increasing complexity
3Volume of moving object
If the dispersive element size is reduced for handheld devices, then the device becomes portable, but the spectral resolution and bandwidth are compromised
Solution Approach 1:
Each light emitter-wavelength pair is optimized for its specific spectral region, with the dispersive element locally optimized for that wavelength range. This local optimization allows smaller dispersive elements to achieve high resolution in their designated bands, while the overall system maintains high spectral resolution through the combined performance of multiple optimized local sections
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 miniaturization of Raman spectrometers to fit into handheld devices, providing accurate detection of skin constituents like Urea, Lactate, and Glucose with improved signal-to-noise ratio and reduced costs.
Implementation Method 1
Raman spectroscopy allows to use laser diodes, which are readily available in the visible or near infrared
Implementation Method 2
The dispersive element is operable to receive light incident on the sensor module and operable to disperse the incident light into spectral components
Implementation Method 3
a single photon detector... The light detector arrangement is operable to generate spectral sensor signals indicative of the spectral components
Implementation Method 4
Raman spectroscopy relies on inelastic light scattering, where a photon excites the sample (Raman Effect). The laser light interacts with molecular vibrations, phonons or other excitations in the system, resulting in the energy of the laser photons being shifted up or down
Data Source
AI summary
A sensor module for Raman spectroscopy includes a sensor package enclosing a light emitter arrangement, a dispersive element and a light detector arrangement arranged on or integrated into a carrier. The light emitter arrangement is operable to emit light with multiple excitation wavelengths out of the sensor module. The dispersive element is operable to receive light incident on the sensor module and operable to disperse the incident light into spectral components. The light detector arrangement is operable to generate spectral sensor signals indicative of the spectral components.