Fiber Optic Probe With Isolated Beam Paths
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Solution Overview
Problem
Conventional fiber optic Raman probes face limitations in throughput and signal quality due to the overlap of excitation and collection beams, which leads to increased background noise and reduced depth of focus, especially in biomedical applications where space and miniaturization are critical.
Innovation Solution
A fiber optic probe design featuring two coaxial but optically isolated and independent beam paths, with a collimated excitation beam and a faster collection beam, allowing for independent optimization of excitation and collection systems to enhance signal overlap and reduce background noise, while maintaining miniaturization for in-vivo applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional fiber optic Raman probes use overlapping excitation and collection beams, then the probe structure is simplified and compact, but the background noise increases and depth of focus is reduced
Solution Approach 1:
The probe is divided into two independent beam paths: an excitation beam path and a collection beam path. These paths are optically isolated to prevent interference between the strong excitation light and the weak Raman signal, thereby reducing background noise while maintaining a compact structure through careful spatial arrangement.
Solution Approach 2:
The harmful overlap between excitation and collection beams is eliminated by extracting the collection beam path from the excitation beam path. The collection optics are positioned to collect Raman scattered light without being contaminated by the direct excitation beam, thus improving measurement precision.
2Volume of moving object
If conventional fiber optic Raman probes use overlapping excitation and collection beams, then the probe size is reduced, but the throughput is limited
Solution Approach 1:
The collection optics are positioned in a different spatial dimension relative to the excitation beam path. By using angular separation and strategic positioning of collection lenses at oblique angles, the probe achieves improved light collection efficiency without increasing the overall probe volume, thus enhancing throughput while maintaining miniaturization.
3Ease of manufacture
If conventional fiber optic Raman probes use simple beam paths, then the device is easier to manufacture, but stray light is not minimized
Solution Approach 1:
Optical elements such as dichroic mirrors and bandpass filters are introduced as intermediaries between the excitation source and the sample, and between the sample and the detector. These elements selectively transmit or reflect specific wavelengths, effectively blocking stray light and Raman scattered light from the excitation beam while allowing the weak Raman signal to reach the detector.
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 design improves the signal-to-noise ratio and depth of focus, enabling more accurate and efficient chemical analysis in confined spaces, particularly suitable for biomedical and industrial applications by decoupling the excitation and collection channels and using filters to minimize stray light.
Implementation Method 1
a delivery light guide comprising one or more than one delivery optical fiber for transmitting excitation radiation from a radiation source
Implementation Method 2
the one or more than one first optical element for forming a substantially collimated illumination beam from the excitation radiation
Implementation Method 3
an optically opaque tubular sleeve fitted over the first optical system to optically isolate the first optical system and the delivery light guide from the second optical system
Implementation Method 4
the second optical system comprising one or more than one second optical element for gathering optical radiation scattered from a sample and forming the optical radiation into a collection beam
Implementation Method 5
one or more than one second optical element for gathering optical radiation scattered from a sample and forming the optical radiation into a collection beam
Implementation Method 6
a collection light guide comprising one or more than one collection optical fiber for accepting the collection beam and transmitting the collection beam to an analyzer
Data Source
AI summary
A fiber optic probe assembly is provided. The probe comprises a first optical system and a second optical system, a delivery light guide comprising one or more than one delivery optical fiber for transmitting excitation radiation from a radiation source disposed at a proximal end of the light guide to the first optical system. The first optical system comprising one or more than one first optical element for forming a substantially collimated illumination beam from the excitation radiation. An optically opaque tubular sleeve is fitted over the first optical system to optically isolate the first optical system and the delivery light guide from the second optical system. The second optical system comprising one or more than one second optical element for gathering optical radiation scattered from a sample and forming the optical radiation into a collection beam. A collection light guide comprising one or more than one collection optical fiber receives the collection beam and transmits the collection beam to an analyzer. The first and second optical systems are disposed within a housing so that an emission cone of the first optical system and an acceptance cone of the second optical system substantially overlap. A spectroscopic measurement system comprising the optic fiber probe is also provided.