Raman Microscopy Device Using Pulsed and Continuous Laser Sources
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Solution Overview
Problem
Current Raman microscopy imaging devices using pulsed laser light sources are costly, sensitive to synchronization and delay requirements, and unsuitable for real-time image generation due to high noise levels, while replacing them with continuous sources results in significantly weaker signals, making them inadequate for applications requiring rapid image production.
Innovation Solution
A Raman microscopy imaging device employing a pulsed laser source for one beam and a continuous laser source for the other, eliminating the need for amplitude modulation and delay stages, and utilizing a reference signal generator to demodulate the measured signal, thereby reducing noise and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pulsed laser light sources are used in Raman microscopy imaging devices, then signal intensity and spectral selectivity are improved, but device cost increases, synchronization complexity increases, and noise levels increase making real-time image generation unsuitable
Solution Approach 1:
The patent divides the laser source configuration into two distinct parts: a pulsed laser source for generating the pump beam and a continuous-wave laser source for generating the Stokes beam. This segmentation allows each laser source to operate independently without synchronization requirements, eliminating the complexity associated with synchronized pulsed sources while maintaining the signal intensity benefits of pulsed excitation for the pump beam
Solution Approach 2:
The patent employs periodic modulation of the continuous-wave Stokes beam using an acousto-optic modulator at a specific frequency (e.g., 80 MHz). This periodic action enables lock-in detection techniques to extract the Raman signal from noise, achieving high measurement precision without requiring synchronized pulsed laser sources, thus resolving the contradiction between signal intensity and device complexity
2Measurement precision
If pulsed laser light sources are used, then signal intensity is improved, but device cost and operational sensitivity to delays increase
Solution Approach 1:
The patent segments the laser source system into a pulsed pump source and a continuous Stokes source, allowing the use of a less expensive continuous-wave laser for the Stokes beam while maintaining high signal intensity through the pulsed pump excitation. This reduces overall device cost compared to using two expensive synchronized pulsed laser sources
Solution Approach 2:
The patent replaces the expensive and complex synchronized pulsed laser source configuration with a combination of a pulsed source and a continuous-wave source plus modulator. This substitution uses more readily available, less expensive components that achieve the same functional outcome without the high cost and sensitivity associated with synchronized pulsed sources
3Device complexity
If continuous laser sources are used instead of pulsed sources, then device cost and complexity are reduced, but signal intensity decreases significantly making real-time image generation inadequate
Solution Approach 1:
The patent applies periodic modulation to the continuous-wave Stokes beam using an acousto-optic modulator driven at a high frequency (e.g., 80 MHz). This periodic modulation enables the use of lock-in detection techniques that significantly enhance the signal-to-noise ratio, allowing real-time image generation with adequate signal intensity while maintaining lower device complexity
Solution Approach 2:
The patent implements lock-in detection feedback mechanisms where the modulated continuous-wave Stokes beam interaction with the sample is detected and processed through phase-sensitive detection. This feedback system continuously optimizes the signal extraction, maintaining high measurement precision despite using a continuous rather than pulsed source configuration
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 configuration allows for cost-effective, stable, and high-quality imaging with reduced noise, enabling reliable real-time image generation and expanding the applicability of Raman microscopy methods like SRS, CARS, and RIKES without the need for additional laser sources.
Implementation Method 1
a first laser light source for emitting a first laser beam having a first wavelength along a first light path; a second laser light source for emitting a second laser beam having a second wavelength, different from the first wavelength
Implementation Method 2
a beam combining element for collinearly combining the two laser beams in one shared light path directed onto a sample
Implementation Method 3
a detector for sensing a measured signal on the basis of the two laser beams interacting with the sample
Data Source
AI summary
A Raman microscopy imaging device (100) is described, having: a first laser light source (12) for emitting a first laser beam (16) having a first wavelength along a first light path (20); a second laser light source (44) for emitting a second laser beam (18) having a second wavelength, different from the first wavelength, along a second light path (22) physically separated from the first light path (20); a beam combining element (32) for collinearly combining the two laser beams (16, 18) in one shared light path (34) directed onto a sample; a detector (38) for sensing a measured signal on the basis of the two laser beams (16, 18) interacting with the sample; and an evaluation unit (40) for evaluating the measured signal sensed by the detector (38). According to the present invention the first laser light source (12) is embodied as a pulsed source, and the second laser light source (44) as a continuous source.