Terahertz Spectroscopic Analysis with Movable-Grating Beam Stabilization
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Solution Overview
Problem
The external resonator type nonlinear quantum cascade laser light source's radiation angle changes with frequency, affecting the terahertz wave irradiation on samples, necessitating sample movement to maintain consistent irradiation, which complicates spectroscopic analysis.
Innovation Solution
A spectroscopic analysis device with a support portion, a light source, a first off-axis parabolic mirror, a first lens, and a photodetector, utilizing a quantum cascade laser element and a movable diffraction grating to stabilize terahertz wave irradiation on a small support area, maintaining consistent irradiation without sample movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the radiation angle of terahertz wave is changed according to frequency, then the light source can emit broadband terahertz waves, but the amount of irradiation of the sample with the terahertz wave changes according to the frequency
Solution Approach 1:
The patent employs dynamic adjustment mechanisms including a movable diffraction grating that changes angle according to frequency, and a movable sample stage that adjusts sample position to track the focused spot. This dynamic compensation ensures consistent irradiation on the sample across the broadband frequency range despite the changing radiation angle of the terahertz waves.
2Manufacturing precision
If the sample is moved according to the frequency of the terahertz wave to maintain constant irradiation, then the irradiation amount remains consistent, but the structure becomes complex and analysis time increases
Solution Approach 1:
The system uses dynamically adjustable components including a movable diffraction grating with angle adjustment mechanism and a movable sample stage with position control. These dynamic elements automatically compensate for frequency-induced radiation angle changes, maintaining consistent sample irradiation without requiring complex manual intervention or overly sophisticated mechanical structures.
3Manufacturing precision
If the sample is moved according to the frequency of the terahertz wave to maintain constant irradiation, then the irradiation amount remains consistent, but the analysis time increases
Solution Approach 1:
The patent implements dynamic compensation mechanisms that automatically adjust the sample position or diffraction grating angle in real-time as frequency changes. This automated dynamic tracking maintains consistent irradiation on the sample throughout the broadband frequency range, eliminating the need for time-consuming manual sample repositioning and significantly reducing total analysis time.
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
The device allows for stable terahertz wave irradiation on a sample, simplifying the structure, reducing analysis time, and improving detection sensitivity by maintaining constant irradiation and preventing moisture absorption.
Implementation Method 1
the light source includes a quantum cascade laser element that generates a first light of a first frequency and a second light of a second frequency, and that emits the terahertz wave of a difference frequency between the first frequency and the second frequency
Implementation Method 2
a first off-axis parabolic mirror that collimates the terahertz wave emitted from the light source
Implementation Method 3
a first lens that focuses the terahertz wave onto the support area, the terahertz wave being collimated by the first off-axis parabolic mirror
Implementation Method 4
a movable diffraction grating that constitutes an external resonator for the first light, and that changes the first frequency by changing an angle of a diffraction grating pattern with respect to the quantum cascade laser element
Implementation Method 5
a photodetector that detects the terahertz wave with which the sample is irradiated
Data Source
AI summary
A spectroscopic analysis device includes a support portion that supports a sample so as to include a predetermined support area; a light source that emits a terahertz wave in a predetermined frequency range; a first off-axis parabolic mirror that collimates the terahertz wave; a first lens that focuses the terahertz wave onto the support area; and a photodetector that detects the terahertz wave with which the sample is irradiated. The light source includes a quantum cascade laser element and a movable diffraction grating. A distance from the light source to the support area via the first off-axis parabolic mirror and the first lens is 10 mm or more and 200 mm or less. An effective diameter of the first lens is 5 mm or more and 80 mm or less. An outer diameter of the support area is 0.5 mm or more and 3.5 mm or less.