Multiple Path Infrared Laser Source for Spectroscopy
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Solution Overview
Problem
Current nonlinear optical frequency conversion techniques for generating long wave infrared laser light are inefficient, resulting in low power delivery in the desired spectral region due to quantum and photon conversion inefficiencies, limiting their effectiveness in spectroscopic detection of hazardous substances.
Innovation Solution
A multiple path light source system utilizing a series of nonlinear difference frequency generators (DFGs) to amplify low power continuous wave laser beams, with a pump laser source generating high power pulsed beams, effectively increasing the power output in the long wave infrared spectral region by cascading the conversion process through multiple DFG stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If nonlinear optical frequency conversion techniques are used to generate long wave infrared laser light, then the spectral region coverage is improved, but the power delivery efficiency deteriorates due to quantum and photon conversion inefficiencies
Solution Approach 1:
The patent divides the frequency conversion process into multiple discrete stages, each using a separate difference frequency generator (DFG) crystal. The first DFG converts pump light at wavelength λp to intermediate wavelength λ1, and the second DFG converts light at wavelength λ1 to final long wave infrared wavelength λLWIR. This segmentation allows optimization of each conversion stage independently, improving overall power delivery efficiency while maintaining broad spectral coverage capability
Solution Approach 2:
The patent introduces an intermediate wavelength stage (λ1) between the pump source and the final long wave infrared output. This intermediary conversion step allows for better matching of photon energies across the conversion stages, reducing quantum efficiency losses and improving overall power delivery to the desired spectral region
2Device complexity
If a single stage frequency conversion is used, then the device complexity is reduced, but the optical conversion efficiency deteriorates due to limited power delivery
Solution Approach 1:
The patent implements continuous cascaded frequency conversion where the output of the first difference frequency generator directly feeds into the second difference frequency generator. This continuous multi-stage conversion process maintains high optical conversion efficiency by ensuring that useful action (light conversion) continues through multiple stages without interruption or significant loss, transforming pump light at λp through intermediate λ1 to final λLWIR in an unbroken conversion chain
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 approach significantly enhances the overall system efficiency, producing higher power output at the desired wavelength with improved optical efficiency, enabling more effective spectroscopic detection of hazardous substances by maintaining a stable phase relationship and coherent combination of beams.
Implementation Method 1
nonlinear optical frequency conversion techniques are another option to convert light from shorter wavelengths into the desired longer wavelengths
Implementation Method 2
A first difference frequency generator (DFG) receives the low power continuous wave light beam having the wavelength λ1 and the high power pulsed laser light beam having the wavelength λ0 and provides a high power pulsed light beam having a wavelength λ1DFG wherein λ1DFG=λ1*λ0/(λ1−λ0)
Implementation Method 3
A beam splitter combines the high power pulsed light beam having the wavelength λ3 from the third DFG with the high power pulsed light beam having the wavelength λ3DFG from the fourth DFG to form a single light beam with the wavelength λ3DFG=λ3
Data Source
AI summary
A multiple path light source has a first and second laser source that generate low power continuous wave laser beam at wavelength λ1 and λ2 respectively. A pump laser source generates a high power pulsed narrow linewidth laser beam at wavelength λ0. A first pair of DFGs convert the low power continuous laser beams at λ1 and λ2 to high peak power pulsed laser beams at wavelengths λ1 and λ2, and generate pulsed laser beams at wavelength λ1DFG=λ1*λ0/(λ1−λ0) and λ2DFG=λ2*λ0/(λ2−λ0). A second pair of DFGs receives the high peak power pulsed laser beams at λ1 and λ2 and the pulsed laser beams at λ1DFG and λ2DFG and generates laser beams at wavelength λ3=λ1*λ2/(λ2−λ1) and λ3DFG=λ1DFG*λ2DFG/(λ2DFG−λ1DFG). A beam splitter combines the high power pulsed laser beam at wavelength λ3 with the high power pulsed laser beam at wavelength λ3DFG to form a single laser light.