Supercontinuum Light Source for High-Speed Spectroscopy

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Solution Overview

Problem

Spectroscopic analysis devices using diffraction gratings are not suited for high-speed analysis due to the need for wavelength sweeping and increased light exposure, and existing research using supercontinuum light has not effectively addressed the analysis of solid-phase and liquid-phase samples in the 1100 to 1200 nm wavelength range due to significant pulse stretching losses.

Innovation Solution

A spectroscopic analysis system employing a pulse laser source, a nonlinear element to generate supercontinuum light, and a pulse stretching element that maintains intensity and broadens pulse width within the 1100 to 1200 nm range, ensuring a one-to-one correspondence between wavelength and time with time dispersion of 10 picoseconds per nanometer and spectral intensity flatness within ±50%.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a diffraction grating is used for spectroscopic analysis, then spectral resolution can be achieved, but high-speed analysis cannot be performed due to the need for wavelength sweeping

Engineering Contradiction:
Improvespectral resolutionVSAvoidanalysis speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent replaces the mechanical diffraction grating system with an optical nonlinear optical crystal system. Instead of mechanically sweeping a diffraction grating to achieve spectral resolution, the invention uses optical parametric oscillation in nonlinear crystals to generate wavelength-tunable light through optical pumping, thereby substituting mechanical motion with optical interaction to achieve both spectral resolution and high-speed measurement capability

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If the amount of light incident on the light receiver is increased to improve measurement SN ratio, then measurement sensitivity improves, but analysis speed decreases

Engineering Contradiction:
Improvemeasurement SN ratioVSAvoidanalysis speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent employs periodic pulsed laser excitation of the nonlinear optical crystal to generate optical parametric oscillation. By using high-repetition-rate pulsed lasers, the system accumulates signal over multiple pulses while maintaining high instantaneous power for efficient nonlinear conversion, thereby achieving high measurement SN ratio without requiring prolonged exposure that would reduce analysis speed

Inventive Principle:
Principle #19Periodic action

3Measurement precision

If light with wavelengths strongly absorbed by the sample is used, then absorption spectrum measurement is possible, but the transmitted light becomes too weak for high SN ratio analysis

Engineering Contradiction:
Improveabsorption spectrum measurement capabilityVSAvoidtransmitted light intensity
Core Design Contradiction:
Measurement precisionVSIllumination intensity

Solution Approach 1:

The patent utilizes the unique property of optical parametric oscillation where the signal and idler wavelengths can be continuously tuned by changing the pump wavelength or crystal temperature. This allows the system to select optimal wavelength combinations where the signal wavelength corresponds to strong absorption features of the sample while the idler wavelength maintains sufficient transmitted intensity for detection, thereby resolving the contradiction between absorption measurement capability and transmitted light intensity

Inventive Principle:
Principle #35Parameter changes

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 high-speed, high-sensitivity spectroscopic analysis of solid-phase and liquid-phase samples with precise spectral resolution in the 1100 to 1200 nm range, overcoming previous limitations in pulse stretching and light intensity loss.

Implementation Method 1

a nonlinear element that outputs supercontinuum light by producing a nonlinear effect in light from the pulse laser source

Methodology Applied
Scientific EffectNonlinear optical effect:

Implementation Method 2

a pulse stretching element that broadens a pulse width of the supercontinuum light from the nonlinear element

Methodology Applied
Scientific EffectPulse stretching:

Data Source

PatentEP3865850B1Light source for spectroscopic analysis, spectroscopic analysis device, and spectroscopic analysis method
Publication Date: 2024.04.17 USHIO INC
  • EP3865850B1 patent drawingFigure 1
  • EP3865850B1 patent drawingFigure 2(1)~2(3)
  • EP3865850B1 patent drawingFigure 3

AI summary

[Object] An optimal structure for spectroscopically analyzing a solid-phase or liquid-phase sample in a wavelength range of 1100 to 1200 nm by using supercontinuum light is provided. [Solution] Supercontinuum light generated by producing nonlinear effects in light from a pulse laser source 1 by a nonlinear element 2 and having a wavelength range including 1100 nm or greater and 1200 nm or less is subjected to pulse stretching by a pulse stretching element 3, and a solid-phase or a liquid-phase sample S is irradiated with the supercontinuum light. In the supercontinuum light, elapsed time and wavelength within one pulse are in a one-to-one correspondence, and computation means 5 computes a spectrum based on a change over time in an output from a light receiver 4 that has received light that has passed through the sample S.