Raman Immersion Probe Achromatic Optics Aberration Correction
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Solution Overview
Problem
Existing Raman probes suffer from significant chromatic aberrations, leading to spectral modifications and varying pathlengths for different wavelengths, which affect the accuracy and consistency of Raman spectra acquisition, especially in samples with solids or varying compositions.
Innovation Solution
The use of achromatically corrected optics, such as achromat or apochromat refractive/diffractive optics, within Raman immersion probes to minimize chromatic and spherical aberrations, ensuring that all wavelengths are focused on the same plane, thereby maintaining consistent pathlengths for improved data accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single lens focused design is used in Raman probes, then the device complexity is reduced, but significant chromatic aberrations are created causing spectral modifications
Solution Approach 1:
The single lens is segmented into multiple lens elements (achromatic doublet or triplet) that work together to correct chromatic aberration. Each lens element is optimized for specific wavelength ranges, allowing the system to maintain simplicity while eliminating spectral distortions.
Solution Approach 2:
The optical parameters of the lens system are changed by introducing multiple lenses with different focal lengths and refractive indices. This parameter modification allows the system to correct chromatic aberration while maintaining a compact form factor suitable for immersion probes.
2Adaptability or versatility
If different focal lengths are selected for different sample types, then the probe can accommodate various samples, but chromatic aberrations increase and spectral modifications occur
Solution Approach 1:
The achromatically corrected optical system provides universal applicability across different sample types (clear liquids, slurries, liquids with solids) by maintaining consistent focal properties for all wavelengths. This eliminates the need to switch between different focal length lenses while preserving spectral accuracy for each sample type.
3Measurement precision
If achromatically corrected optics are used, then chromatic and spherical aberrations are minimized, but the device complexity increases
Solution Approach 1:
The complex aberration correction is achieved through segmentation of the optical path into multiple lens elements (achromatic doublet or triplet). Each segment is designed to correct specific aberrations, and their combined effect provides comprehensive correction with minimal additional complexity.
Solution Approach 2:
The optical system uses composite lens designs combining different glass materials with complementary optical properties. This allows the system to correct multiple aberration types simultaneously while maintaining a compact and manageable optical structure.
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
This solution minimizes aberration zones, enhancing sensitivity and accuracy of Raman measurements, facilitating consistent calibration transfer between instruments and reducing the need for frequent recalibration, while allowing for more precise and reliable chemical component analysis.
Implementation Method 1
The achromatically corrected optic may be an achromat comprising a lens doublet or an achromat comprising a lens triplet or more optical elements
Implementation Method 2
the achromatically corrected optic at the distal end of the probe body focuses the laser excitation beam onto or within the sample and collimates the collection beam from the sample
Implementation Method 3
optic designs that are achromatically corrected to limit the effects of chromatic and spherical aberration
Implementation Method 4
optic designs that are achromatically corrected to limit the effects of chromatic and spherical aberration
Data Source
AI summary
Achromatically corrected Raman immersion probes minimize chromatic and/or spherical aberration through the use of an achromat, apochromat, refractive/diffractive optics as opposed to a single lens geometry. The improved end optics are adapted for use with a probe body carrying a laser excitation and/or collection beam associated with Raman analysis. The achromatically corrected optic to focus the beam onto or within a sample. The sample may be a gas, a liquid, or a partial liquid such as a slurry. The achromatically corrected optic may be an achromat comprising a lens doublet or an achromat comprising a lens triplet or more optical elements. In one preferred embodiment, the achromatically corrected optic may be an apochromatic optic. A disclosed system includes the achromatically corrected end optic and Raman probehead operative to send and receive counter-propagating laser excitation and collection beams.