Supercontinuum Laser Spectroscopy Speckle Reduction
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Solution Overview
Problem
Current sample investigation systems using electromagnetic radiation face limitations in achieving high intensity, directional beams with extensive spectral broadening and coherence, leading to interference effects like speckle, which complicates data interpretation in reflectometer, spectrophotometer, ellipsometer, and polarimeter systems, and require reconfiguration for different wavelength ranges.
Innovation Solution
The use of a supercontinuum laser source providing a high intensity, highly directional beam over 400-2500 nm, combined with optimized detector systems and speckle reducers like Optotune Elastoactive Polymer and Reflective Force LSRs, and dichroic beam splitter-prism combinations to manage wavelength dispersion and stabilize beam intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a supercontinuum laser source is used to provide high intensity, highly directional electromagnetic radiation over a wide spectral range (400-2500 nm), then the beam intensity and directional properties are improved, but speckle interference effects are generated that complicate data interpretation
Solution Approach 1:
A rotating diffuser is introduced as an intermediary component between the supercontinuum laser source and the sample. The diffuser scattering the coherent laser light into multiple incoherent beams, which then combine to form an illuminated spot on the sample. This intermediary element eliminates speckle interference while preserving the high intensity and directional properties of the original laser beam.
2Adaptability or versatility
If conventional electromagnetic radiation sources are used in sample investigation systems, then system complexity is reduced, but the ability to achieve extensive spectral broadening (400-2500 nm) with high coherence is limited
Solution Approach 1:
The supercontinuum laser source is employed as a universal illumination source that can provide coherent electromagnetic radiation across the entire 400-2500 nm spectral range simultaneously. This single multi-functional source replaces what would traditionally require multiple separate light sources tuned to different wavelength ranges, thereby extending spectral coverage while managing system complexity through consolidation.
3Measurement precision
If a single detector system is used to detect electromagnetic radiation over the entire 400-2500 nm range, then device complexity is reduced, but measurement precision is compromised due to inability to optimize for specific wavelength ranges
Solution Approach 1:
The detection system is segmented into multiple detector modules, each optimized for specific wavelength sub-ranges within the 400-2500 nm spectrum. Optical elements such as dichroic beam splitters and gratings direct different wavelength ranges to appropriate detectors, allowing each detector to operate at optimal sensitivity for its assigned range, thereby improving overall measurement precision.
4Measurement precision
If the system is configured for specific wavelength ranges, then measurement precision for those ranges is improved, but adaptability to investigate samples across different wavelength ranges requires frequent reconfiguration
Solution Approach 1:
The system incorporates dynamic, reconfigurable optical elements including rotatable gratings, movable dichroic beam splitters, and adjustable detector positioning mechanisms. These dynamic components allow the system to be quickly reconfigured between different wavelength ranges and measurement modes without requiring physical reassembly, thereby maintaining measurement precision across various ranges while improving adaptability.
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
Enables convenient sample investigation over a wide range of wavelengths with improved consistency and reduced speckle effects, allowing for more accurate property evaluation without the need for frequent system reconfiguration.
Implementation Method 1
a source of a beam of electromagnetic radiation provided by a super continuum laser, and applies detector systems that direct wavelengths, via functional combinations of gratings and/or combination dichroic beam splitter-prisms
Implementation Method 2
interaction of a typically pulsed laser and many non-linear processes to cause extensive spectral broadening
Implementation Method 3
via functional combinations of gratings and/or combination dichroic beam splitter-prisms, (which can be optimized as regards wavelength dispersion characteristics)
Implementation Method 4
combination dichroic beam splitter-prisms
Implementation Method 5
The present invention preferably also comprises application of a speckle reducer to minimize effects of interference caused by coherence
Implementation Method 6
Detected changes in Intensity (in reflectometer and spectrophotometer systems), and Polarization State (in ellipsometer, and polarimeter systems), as a result of said interaction provide insight to properties of the sample
Data Source
AI summary
Reflectometer, spectrophotometer, ellipsometer, and polarimeter systems having a supercontinuum laser source of coherent electromagnetic radiation over a range of about 400-about 2500 nm, a stage for supporting a sample and a detector of electromagnetic radiation, wherein the supercontinuum source provides a coherent beam of electromagnetic radiation which interacts with a sample, and the detector system comprises functional combinations of gratings and/or combination dichroic beam splitter-prisms, which themselves can be optimized as regards wavelength dispersion characteristics, directs wavelengths in various ranges to various detectors that are well suited to detect them.