Compact CARS Optical Head Using Segmented Rigid Frames
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Solution Overview
Problem
Current CARS spectroscopy systems are bulky and not suitable for portable or wearable applications due to the need for precise alignment of multiple optical elements, which complicates the integration of a compact and stable optical head for nonlinear Raman spectroscopy.
Innovation Solution
The optical head is designed with separate, highly rigid frames for each optical module, allowing for precise positioning and adjustment of optical elements, including a mechanism for fine adjustment and fixation of optical elements, enabling compact integration and alignment of pump and Stokes light paths for efficient CARS light generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple optical elements are precisely aligned on a large stable stage for CARS spectroscopy, then measurement precision is improved, but device complexity and size increase
Solution Approach 1:
The optical system is divided into separate modules, each with its own rigid frame structure. The pump light optical system and Stokes light optical system are independently aligned and then integrated, allowing precise alignment within each module without requiring the entire system to be mounted on a large stage.
Solution Approach 2:
The patent replaces the traditional mechanical stage-based alignment system with a rigid frame structure that provides stable optical paths. The frames are designed with high rigidity to maintain precise optical alignment without requiring complex mechanical adjustment mechanisms or large stable stages.
2Ease of operation
If a compact optical head is designed for portability, then ease of operation is improved, but manufacturing precision becomes more difficult to maintain
Solution Approach 1:
The optical head is segmented into multiple rigid frame modules that can be manufactured separately with precise tolerances and then assembled. This allows each module to be optimized for compactness while maintaining manufacturing precision through modular construction rather than requiring the entire system to be manufactured as a single large precision component.
Solution Approach 2:
The frames are designed with high rigidity to maintain optical alignment precision in a compact structure. The use of rigid frame structures provides the necessary stability for precise optical element positioning without requiring a large overall system size, enabling portability while maintaining manufacturing precision.
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 allows for a compact, portable optical head that can precisely concentrate and collect light for nonlinear Raman effects, enhancing the generation and measurement of CARS light, even with low-energy laser sources, while maintaining precise control over focal positions.
Implementation Method 1
Coherent Anti-Stokes Raman Scattering (hereinafter referred to as 'CARS'), which is one form of nonlinear Raman spectroscopy, is capable of amplifying weak Raman signals and obtaining Raman images at high speed. The CARS process usually requires two light pulses of different wavelengths (called 'pump light' and 'Stokes light'), and when the frequency difference of the light pulses matches the molecular vibration, very intense CARS light is generated.
Implementation Method 2
a method (called 'multicolor CARS spectroscopy' or 'multiplex CARS spectroscopy') that spectrally detects generated CARS light using a broadband light source as the Stokes light is known. With this method, since the Raman spectrum can be estimated from the spectrum of CARS light, more information can be acquired than with a method that detects only a specified spectrum component, which means more information can be acquired in a short time. One way to obtain broadband Stokes light is to use a phenomenon whereby broadband light (called 'supercontinuum light') is internally generated when laser light is introduced into an optical fiber such as a photonic crystal fiber (PCF).
Implementation Method 3
After the supercontinuum light exits the PCF, only components with a wavelength that is longer than the pump light (excitation light) are extracted using a long pass filter
Implementation Method 4
the extracted components are used as the Stokes light, are combined with the pump light using a dichroic mirror or the like
Data Source
AI summary
An optical head includes a first module that concentrates pump light and Stokes light on a first point; a second module that collects CARS light from the first point; and a third module that supports the first module and the second module. The first module includes: a high rigidity first frame; and a first optical system including a plurality of optical elements fixed to the first frame. The second module includes: a high rigidity second frame; and a second optical system including a plurality of optical elements fixed to the second frame. The third module includes a high rigidity third frame that fixes the first frame and the second frame.