Infrared Spectrophotometer Control Light Detector Inclined Surface
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Solution Overview
Problem
Current Fourier transform infrared spectrophotometers face challenges in obtaining accurate interferograms due to variations in the orientation of moving mirrors, leading to intensity and phase changes in the infrared interference light beam, which affect the quality of the measured interferogram.
Innovation Solution
The implementation of a Fourier transform infrared spectrophotometer design that includes a main interferometer, a control interferometer, an infrared detector, a control light detector, and a beam splitter block, with the control light detector having an incident surface with a normal line inclined relative to the optical axis of the control interference light beam, and the use of a collimation optical system or waveplate with an optical axis inclined relative to the control light beam to reduce stray light overlap and improve mirror orientation and position accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional Fourier transform infrared spectrophotometer uses a standard control light detector with the incident surface normal to the optical axis, then the device structure is simple, but stray light overlaps with the control interference light beam causing reduced measurement precision
Solution Approach 1:
The control light detector's incident surface is designed with an inclined angle relative to the optical axis, breaking the symmetric configuration. This asymmetric design causes the detected control interference light beam to be directed away from the optical axis, preventing overlap with stray light that travels along the optical axis, thereby improving interferogram accuracy
Solution Approach 2:
The solution moves the control interference light beam detection from the one-dimensional optical axis to a different spatial dimension by inclining the incident surface. This dimensional change separates the control light path from the stray light path in space, eliminating interference while maintaining structural feasibility
2Reliability
If the moving mirror orientation varies during operation, then the device can accommodate movement, but intensity and phase changes occur in the infrared interference light beam reducing measurement precision
Solution Approach 1:
The control interferometer generates a control interference light beam that provides feedback information about the moving mirror's position and orientation. By detecting this control beam with the inclined incident surface detector, the system can monitor and compensate for mirror variations, maintaining interferogram quality despite mechanical movements
3Measurement precision
If stray light is present in the optical path, then the optical system is simple, but the control interference light beam overlaps with stray light reducing measurement precision
Solution Approach 1:
The inclined incident surface design extracts the control interference light beam detection from the main optical axis path. By separating the control light detection direction from the stray light path, the harmful stray light is effectively removed from the measurement process, improving detection accuracy
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 design enhances the accuracy of the interferogram and power spectrum measurements by accurately setting the speed and orientation of the moving mirror and detecting its position, resulting in a more stable and precise interferogram with reduced temporal changes.
Implementation Method 1
a beam splitter, a fixed mirror, and a moving mirror
Implementation Method 2
A Fourier transform infrared spectrophotometer includes a main interferometer, a control interferometer
Implementation Method 3
The infrared detector detects an infrared interference light beam
Implementation Method 4
The control light detector has an incident surface, the incident surface having a normal line inclined with respect to an optical axis of the control interference light beam
Data Source
AI summary
A Fourier transform infrared spectrophotometer includes a main interfersometer, a control interferometer, an infrared detector, a control light detector, and a beam splitter block. The beam splitter block is disposed between a beam splitter and the control light detector. The control light detector has an optical axis inclined with respect to an optical axis of a control interference light beam.