Optical Probe Diffractive Microstructure Achromatic Focusing
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Solution Overview
Problem
Commercially available optical coherent tomography probes require frequent changes when switching between different wavelengths, leading to deviations in detection positions and prolonged operation times due to the need for recalibration of the optical path.
Innovation Solution
An optical probe with a cylindrical lens featuring a curved end surface and a concentric ring-shaped diffractive microstructure, which maintains a consistent working position across different wavelengths by optimizing diffraction efficiency and refraction effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single probe is used for multiple wavelengths, then probe complexity is reduced, but working position stability deteriorates due to chromatic dispersion
Solution Approach 1:
The patent changes the optical parameters of the lens system by introducing a diffractive microstructure with specific groove depths and patterns that compensate for chromatic dispersion. The groove depth is optimized to create wavelength-dependent phase delays that counteract the natural focal shift, thereby stabilizing the working position across multiple wavelengths while using a single probe structure.
Solution Approach 2:
The patent combines refractive optics (cylindrical lens) with diffractive optics (microstructure with concentric grooves) to create a hybrid optical element. This composite structure leverages both refraction and diffraction effects to achieve achromatic focusing, allowing a single probe to maintain stable working position across a broad wavelength range from 750 nm to 1700 nm.
2Adaptability or versatility
If the wavelength of incident light is changed, then detection capability is improved, but working position deviates due to chromatic dispersion
Solution Approach 1:
The diffractive microstructure is designed with wavelength-specific groove depths that create compensating phase shifts. When the wavelength of incident light changes, the diffraction pattern shifts in a controlled manner that counteracts the chromatic dispersion of the cylindrical lens, thereby maintaining accurate working position and detection precision across different wavelengths.
Solution Approach 2:
The diffractive microstructure acts as an intermediary element between the cylindrical lens and the target tissue. It mediates the wavelength-dependent focal shifts by introducing compensating optical path differences, ensuring that detection remains precise across the broad wavelength range without requiring probe changes or recalibration.
3Measurement precision
If probes are changed for different wavelengths, then detection accuracy is maintained, but operation time increases due to recalibration requirements
Solution Approach 1:
The patent designs a universal probe structure with a diffractive microstructure that functions across multiple wavelengths (750 nm to 1700 nm) without requiring changes or recalibration. The concentric groove pattern is optimized to provide achromatic focusing for the entire wavelength range, allowing the single probe to perform detection accurately at all wavelengths, thereby eliminating time-consuming probe changes and recalibration procedures.
4Adaptability or versatility
If a broad wavelength range is covered, then versatility is improved, but diffraction efficiency decreases at wavelength extremes
Solution Approach 1:
The diffractive microstructure parameters (groove depth, groove width, groove spacing) are optimized as a function of wavelength to maintain high diffraction efficiency across the broad range. The groove depth is specifically designed to create constructive interference at the desired focal point for each wavelength, minimizing energy loss and maximizing diffraction efficiency even at the extremes of the 750 nm to 1700 nm range.
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
The optical probe achieves a consistent working position for wavelengths between 750 nm and 1700 nm, reducing the need for probe changes and maintaining high diffraction efficiency across the wavelength range, thereby enhancing the accuracy and efficiency of optical coherent tomography applications.
Implementation Method 1
When the incident light having a first wavelength passes through the cylindrical lens, the incident light produces a diffraction effect with the diffractive microstructure and is converged at a first wavelength working position
Implementation Method 2
After the incident light having a second wavelength is refracted by the curved end surface of the cylindrical lens, the incident light with the second wavelength is converged at a second wavelength working position
Data Source
AI summary
An optical probe includes a cylindrical lens adapted to receive and transmit incident light. A light-emitting surface of the cylindrical lens is a curved end surface having a concentric ring-shaped diffractive microstructure. A working position of the optical probe is a position where a diffraction order is 1 when the incident light having a design wavelength between a first wavelength and a second wavelength passes through the diffractive microstructure. When passing through the cylindrical lens, the incident light having the first wavelength produces a diffraction effect with the diffractive microstructure and is converged at a first wavelength working position approximately the same as the working position of the optical probe with the diffraction order of 1. After being refracted by the curved end surface, the incident light having the second wavelength is converged at a second wavelength working position approximately the same as the working position of the optical probe.