Frustum Shaped Reflective Cavity for Sub-Surface Spectroscopy
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Solution Overview
Problem
Conventional optical spectroscopy methods are limited in measuring non-uniform samples and diffusely scattering samples, as they only measure a small volume and can cause damage to delicate samples, and fail to capture sub-surface signals from diffusely scattering samples.
Innovation Solution
A light delivery and collection device with a reflective cavity that diverges excitation light over a large area, allowing for sub-surface signal excitation and collection, using a specular reflective surface to enhance signal collection efficiency and prevent sample damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a well-focused laser beam is used to produce inelastic scattering and fluorescence signal, then signal excitation efficiency is improved, but the measurement volume is limited to a small area and sub-surface signals cannot be obtained
Solution Approach 1:
The invention divides the light delivery function into two separate components: a focused laser beam delivery system for efficient signal generation, and a reflective cavity for expanding the measurement area. This segmentation allows each component to optimize its specific function without compromising the other.
Solution Approach 2:
The reflective cavity acts as an intermediary between the focused laser beam and the sample. It takes the concentrated light from the laser and redistributes it across a larger sample area through multiple reflections, enabling both efficient excitation and broad coverage.
2Productivity
If a well-focused laser beam is used, then signal excitation efficiency is improved, but delicate samples may be damaged
Solution Approach 1:
The system separates the light delivery function (focused beam for efficiency) from the light interaction function (distributed illumination through reflective cavity to prevent damage). This allows high intensity light to be delivered without concentrating all energy on a single point of the sample.
Solution Approach 2:
The reflective cavity creates multiple partial reflections of the laser beam, distributing the total light energy across multiple passes and locations. This partial action approach prevents excessive energy concentration that would damage delicate samples while maintaining overall excitation efficiency.
3Measurement precision
If a well-focused laser beam is used on diffusely scattering samples, then surface signal is obtained, but sub-surface material cannot be measured
Solution Approach 1:
The reflective cavity serves as an intermediary that enables light to penetrate deeper into diffusely scattering samples. By creating multiple reflection paths and increasing the effective path length of light within the sample, it allows excitation and detection of signals from sub-surface regions that would be inaccessible with direct focused illumination.
Solution Approach 2:
The reflective cavity creates continuous light circulation within the sample region, with light repeatedly interacting with the sample material through multiple reflections. This continuous action increases the probability of light reaching sub-surface regions and returning signals to the detector, enabling deep tissue or material analysis.
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 representative measurement of both surface and sub-surface signals from large areas of non-uniform and diffusely scattering samples, improving collection efficiency and reducing sample damage.
Implementation Method 1
The reflective cavity has a specular reflective surface with high reflectivity to the excitation light as well as to the inelastic scattering and/or fluorescence emission from the subject
Implementation Method 2
Such interaction includes inelastic scattering processes, such as Raman and Brillouin scattering
Implementation Method 3
Such interaction includes inelastic scattering processes, such as Raman and Brillouin scattering, and fluorescence emission process
Data Source
AI summary
This invention relates to a light delivery and collection device for performing spectroscopic analysis of a subject. The light delivery and collection device comprises a reflective cavity with two apertures. The first aperture receives excitation light which then diverges and projects onto the second aperture. The second aperture is applied to the subject such that the reflective cavity substantially forms an enclosure covering an area of the subject. The excitation light interacts with the covered area of the subject to produce inelastic scattering and/or fluorescence emission from the subject. The reflective cavity reflects the excitation light as well as the inelastic scattering and/or fluorescence emission that is reflected and/or back-scattered from the subject and redirects it towards the subject. This causes more excitation light to penetrate into the subject hence enabling sub-surface measurement and also improves the collection efficiency of the inelastic scattering or fluorescence emission. The shape of the reflective cavity is optimized to further improve the collection efficiency.