Non-linear Spectroscopy Frequency Conversion
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Solution Overview
Problem
Current FTIR spectrometers face challenges in detecting optical properties of samples in mid- to long-infrared ranges due to inadequate sensitivity and cost-effectiveness of detectors, leading to poor signal-to-noise ratios and the need for complex, expensive cooling systems.
Innovation Solution
A non-linear optical spectroscopy procedure involving the generation of signal and idler radiation through parametric fluorescence in a non-linear optical medium, allowing for coherent phase manipulation and interference pattern recording, which is then transformed into a frequency spectrum using Fourier transformation, enabling detection in frequency ranges where sensitive detectors are scarce.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If FTIR spectrometers use broad-band stimulus radiation with interferometry, then spectral resolution is improved, but detection sensitivity deteriorates in mid- to long-infrared ranges due to thermal noise
Solution Approach 1:
The patent changes the frequency parameters of the radiation by using parametric fluorescence to generate signal radiation at frequencies where detectors are more sensitive. The pump radiation at frequency ωp generates signal radiation at frequency ωs and idler radiation at frequency ωi, where ωs + ωi = ωp, shifting the detection to a more favorable frequency range.
Solution Approach 2:
The patent introduces a non-linear optical medium as an intermediary that converts the broad-band pump radiation into narrow-band signal and idler radiation through parametric fluorescence. This intermediary process enables the use of sensitive detectors in the visible to near-infrared range for detecting mid-infrared sample properties.
2Reliability
If cooling systems are used to reduce thermal noise in detectors, then detection sensitivity is improved, but device complexity and cost increase
Solution Approach 1:
The non-linear optical medium acts as an intermediary that translates mid-infrared radiation into visible to near-infrared radiation, enabling the use of uncooled, cost-effective detectors. This eliminates the need for complex cooling systems while maintaining detection sensitivity.
Solution Approach 2:
The patent replaces the mechanical cooling system with an optical frequency conversion process. Instead of physically cooling the detector to reduce thermal noise, the system converts the radiation frequency so that standard detectors can operate effectively without cooling.
3Adaptability or versatility
If detectors are used in mid- to long-infrared ranges, then spectral coverage is improved, but detection cost-effectiveness deteriorates due to expensive cooling requirements
Solution Approach 1:
The patent changes the frequency parameter of the detected radiation through parametric fluorescence. The signal radiation is generated at frequencies where inexpensive, uncooled detectors are available, while still providing coverage of the mid-infrared spectral range through the frequency relationship ωs + ωi = ωp.
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 the recording of sample properties across a large frequency range with cost-effective detectors, improving signal-to-noise ratios and simplifying the detection process by leveraging quantum mechanical effects to shift idler radiation into more accessible frequency ranges.
Implementation Method 1
generate a first signal radiation and first idler radiation from a part of the pump radiation using a first parametric fluorescence in a non -linear optical medium
Implementation Method 2
Spatial overlapping of the first signal radiation and the second signal radiation... capture of an intensity of an intensity exclusively of the spatially overlaid first and second signal radiation depending on the distance difference
Implementation Method 3
generation of a frequency spectrum of the first Idler radiation by transforming the way length interference pattern depends on the distance difference into the frequency spectrum
Data Source
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AI summary
The present invention relates to a method and an apparatus for nonlinear optical spectroscopy on a sample, wherein a first signal and idler radiation is generated by means of a first parametric fluorescence in a nonlinear optical medium, wherein a second signal and idler radiation is generated by means of a second parametric fluorescence in a nonlinear optical medium, wherein the first and second idler radiation are coherent to each other, wherein the first and second signal radiation are spatially superimposed, wherein the first signal radiation travels an optical signal path length and the first idler radiation travels an optical idler path length.wherein a path length difference between the optical signal path length and the optical idler path length is changed, and wherein a path length interference pattern of an intensity exclusively of the spatially superimposed first and second signal radiation is detected after a spatial superposition of the first and second idler radiation in the nonlinear optical medium of the second parametric fluorescence as a function of the path length difference, and wherein subsequently a frequency spectrum of the first idler radiation is generated by transforming the path length interference pattern dependent on the path length difference into the frequency spectrum.