Linear Raman Beam Shaping for Uniform SERS Signal Detection
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Solution Overview
Problem
Raman spectroscopy on uneven substrates like SERS chips results in irregular signal distribution, leading to 'hotspots' and weak signals, and existing solutions like rastering are costly and cumbersome.
Innovation Solution
A lensless Raman probe with an attachment that reshapes collimated light into a linear shape, using optical components to interrogate a more geographically diverse area of the sample without mechanical movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a circular Gaussian beam is used for Raman spectroscopy on uneven substrates, then the beam can be easily delivered to the sample, but the signal distribution becomes irregular with hotspots and weak signals
Solution Approach 1:
The patent transforms the symmetric circular Gaussian beam into an asymmetric linear shaped beam by removing the focusing lens and using cylindrical optics. This asymmetric shape better matches the linear features of SERS chip substrates, eliminating hotspots and providing uniform signal distribution across the interrogation area.
Solution Approach 2:
The linear shaped beam concentrates optical energy along a linear path rather than distributing it circularly. This local quality change ensures that the beam intensity is uniformly distributed along the linear dimension, matching the substrate geometry and providing consistent Raman signal across the entire interrogation area.
2Device complexity
If a circular beam is used to interrogate the sample, then the setup is simple, but relocating the beam to cover different areas requires complicated mechanical operations
Solution Approach 1:
The patent enables dynamic reconfiguration of the interrogation area by rotating the linear shaped beam around the sample center. This simple rotational movement allows the beam to cover different angular sectors of the sample without requiring complex translational mechanisms, achieving versatile area coverage with minimal mechanical complexity.
3Device complexity
If the focusing lens is removed to create a lensless probe, then the device complexity is reduced, but the beam shape control becomes more challenging
Solution Approach 1:
The patent replaces the spherical focusing lens (mechanical optical element) with a combination of cylindrical lens and cylindrical mirror. This substitution creates the linear shaped beam through geometric optics rather than spherical focusing, simplifying the overall probe structure while maintaining precise beam shape control.
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
Enhances Raman signal detection by covering a broader sample area with a linear beam, providing a more complete and accurate analysis with improved signal quality.
Implementation Method 1
an optical component (e.g., a flat mirror) positioned within the optics housing, which redirects the collimated light along the pathway defined by the pathway as a first light beam
Implementation Method 2
a focusing component positioned within the optics housing (e.g., a cylindrical focusing mirror, such as a concave mirror), which redirects the first light beam as a second (e.g., focused) light beam having a linear shape
Implementation Method 3
The laser photons (also sometimes referred to as a Raman pump) inelastically scatter, or 'Raman scatter,' off the molecules in the sample and experience wavelength shifting to new frequencies given by bond vibrational frequencies present in the molecules of the sample
Data Source
AI summary
Systems and methods for obtaining a Raman signal from a sample. One example provides an optical analysis system including a light source generating an excitation light, wherein the excitation light is collimated light having a first shape, an optical component configured to redirect the excitation light as a first light beam, and a focusing component configured to redirect the first light beam as a second light beam. The second light beam interrogates the sample at a predetermined distance from the focusing component in a linear shape.