Frequency-Dependent Refractive Index Determination Without Wavelength Scan
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Solution Overview
Problem
Current methods for determining frequency-dependent refractive indices are time-consuming and require a reference prism and wavelength scan, limiting their precision and applicability.
Innovation Solution
A method using collimated, polychromatic light to directly determine frequency-dependent refractive indices by comparing the spectral intensity distribution with the spatial intensity distribution on a material sample, eliminating the need for a reference prism and wavelength scan, and incorporating a computing unit to account for the geometric shape and arrangement of the radiation source, material sample, and detector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If total reflection refractometers are used to determine refractive index, then the Abbe number can be determined using polychromatic light, but the frequency-dependent refractive indices can only be estimated and contact fluids severely restrict the operating range and material choice
Solution Approach 1:
The invention extracts the measurement function from the complex reference prism system and contact fluid requirements, using only the material sample itself as the refracting element. By directing collimated polychromatic light through the material sample and detecting the spatial intensity distribution of the transmitted light, the method eliminates the need for reference prisms and contact fluids, thereby expanding material compatibility while maintaining measurement capability
Solution Approach 2:
The invention introduces a computing unit that acts as an intermediary to process the relationship between spectral intensity distribution and spatial intensity distribution. This computational mediator calculates frequency-dependent refractive indices by analyzing how different wavelengths are spatially distributed after passing through the material sample, enabling precise determination without physical reference standards
2Measurement precision
If differential refractometers with goniometers and prism spectrometers are used to determine frequency-dependent refractive indices, then the refractive index can be determined for each wavelength, but a wavelength scan must be performed which is time-consuming and requires calibration
Solution Approach 1:
The invention segments the spectral information capture by using a detector with spatial resolution that simultaneously detects different wavelengths at different spatial positions. Instead of sequentially scanning wavelengths, the system captures the entire spectral distribution in parallel across the detector array, enabling all wavelength measurements to be completed in a single shot without time-consuming scans
Solution Approach 2:
The invention replaces the mechanical wavelength scanning system (goniometers and prism spectrometers) with a computational approach. The computing unit substitutes for the mechanical scanning mechanism by calculating refractive indices from spatial intensity distribution data, eliminating moving parts and calibration requirements while maintaining measurement precision
3Measurement precision
If a reference prism and wavelength scan are used to determine frequency-dependent refractive indices, then the measurement can be performed, but the process is time-consuming and requires calibration of the wavelength
Solution Approach 1:
The invention extracts the wavelength calibration function from the measurement system by using the material sample itself as the reference. By measuring the spatial intensity distribution of light transmitted through the material sample and comparing it with the known spectral intensity distribution, the system directly calculates frequency-dependent refractive indices without requiring external wavelength calibration standards or reference prisms
Solution Approach 2:
The material sample serves itself as the measurement object and reference standard simultaneously. The system uses the material sample's own optical properties to generate the spatial intensity distribution pattern, which is then analyzed to determine its frequency-dependent refractive indices, eliminating the need for separate calibration procedures and reference materials
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 quick and precise determination of frequency-dependent refractive indices without a wavelength scan, enhancing robustness and flexibility, suitable for series measurements and in-line process monitoring, and reducing costs.
Implementation Method 1
The refractive index is an optical material property that indicates the ratio of the wavelength of light in a vacuum to the wavelength of light in the material, and thus also the ratio of the phase velocity of light in a vacuum to that in the material. The refractive index depends on the frequency of the light, a phenomenon known as dispersion.
Implementation Method 2
The refractive index depends on the frequency of the light, a phenomenon known as dispersion.
Data Source
Figure 1~2c
Figure 3a~3b
AI summary
The invention relates to a method for determining frequency-dependent refractive indices (12) of a material sample (10), having the steps of: a) providing the material sample (10), said material sample (10) having at least one inlet side (18) and an outlet side (20), b) irradiating the inlet side (18) with collimated polychromatic light (24a) with a spectral intensity distribution (26) by means of a radiation source (22), c) detecting the spatial intensity distribution (30) of the light (24b) on the outlet side (20) using a spatially resolving detector (32) on a propagation plane (28), and d) ascertaining the frequency-dependent refractive index (12) of the material sample (10) by comparing the spectral intensity distribution (26) with the detected spatial intensity distribution (30) by means of a computing unit (38) while taking into consideration the geometric shape of the material sample (10) and the arrangement of the radiation source (22), the material sample (10), and the detector (32) relative to one another.