Hyperspectral Refractometer with Diffraction Grating
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Solution Overview
Problem
Conventional refractometers are limited in their ability to perform real-time and continuous multi-wavelength refractive index measurements due to the use of single wavelength sources and moving parts, which restricts their capability to observe refractive index changes and produce continuous dispersion profiles.
Innovation Solution
A refractometer system comprising a focusing optical system and a dispersive optical system, including a diffraction grating and cylindrical lenses, that directs and spectrally spreads an optical beam across a range of wavelengths and angles of incidence, allowing for the detection of critical angles and refractive index determination using critical pixel locations and calibration relationships.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional refractometers use single wavelength sources or filtered light, then measurement simplicity is maintained, but multi-wavelength measurement capability is lost
Solution Approach 1:
The optical beam is segmented into multiple wavelengths using a dispersive optical system with diffraction gratings, allowing simultaneous measurement across multiple wavelengths without requiring multiple light sources or complex mechanical scanning mechanisms
Solution Approach 2:
The patent introduces spectral dimension by dispersing light into its component wavelengths, transforming a single-wavelength measurement system into a multi-wavelength system through the addition of dispersive elements that separate light by wavelength
2Productivity
If conventional refractometers use moving parts for multi-wavelength measurement, then wavelength tuning is achieved, but real-time continuous measurement capability is reduced
Solution Approach 1:
The patent replaces mechanical scanning systems with a stationary optical system that uses diffraction gratings and cylindrical lenses to simultaneously direct multiple wavelengths at the prism interface, eliminating moving parts and enabling real-time continuous measurement
Solution Approach 2:
Multiple wavelength measurements are merged into a single simultaneous measurement process by using a broadband light source and dispersive optics to illuminate the prism interface with all wavelengths at once, rather than sequentially switching between wavelengths
3Measurement precision
If conventional refractometers perform serial measurements, then device simplicity is maintained, but spectral resolution and signal-to-noise ratio are degraded
Solution Approach 1:
The patent implements continuous simultaneous measurement of multiple wavelengths by maintaining a steady broadband optical beam throughout the system, allowing all spectral measurements to occur continuously rather than in discrete sequential steps, thereby improving both spectral resolution and signal-to-noise ratio
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 multi-wavelength refractive index measurement for a range of wavelengths simultaneously, facilitating hyperspectral and real-time monitoring of refractive index changes without the need for mechanical scanning, improving spectral resolution and reducing signal-to-noise ratio.
Implementation Method 1
the dispersive optical system comprises a diffraction grating configured to spectrally spread the optical beam by imposing a wavelength dependent angular dispersion along a first axis
Implementation Method 2
a cylindrical lens configured to collimate the spectrally spread optical beam along the first axis to produce a collimated spectrally spread optical beam
Implementation Method 3
directing an optical beam that includes a range of wavelengths to be incident on an interface between the sample and a prism at a range of angles of incidence including a critical angle
Data Source
AI summary
Refractometers for simultaneously measuring refractive index of a sample over a range of wavelengths of light include dispersive and focusing optical systems. An optical beam including the range of wavelengths is spectrally spread along a first axis and focused along a second axis so as to be incident to an interface between the sample and a prism at a range of angles of incidence including a critical angle for at least one wavelength. An imaging detector is situated to receive the spectrally spread and focused light from the interface and form an image corresponding to angle of incidence as a function of wavelength. One or more critical angles are identified and corresponding refractive indices are determined.