Spectroscopy Optical Layout for Sub-Wavelength Interferogram Sampling
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Solution Overview
Problem
Existing optical devices face limitations in enhancing the resolution of spectral information due to restricted sampling intervals of measurement light, which hinders the ability to widen the band of measurable wavelengths, particularly for short-wavelength light.
Innovation Solution
The optical device incorporates a first optical system with a movable mirror and a second optical system using laser interferometry to measure the mirror's position, combined with a signal generator and calculation device to generate and transform interferograms, allowing for high-resolution spectral information acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the intensity change of laser light is used as a trigger for sampling, then the position of the movable mirror can be detected, but the sampling interval is restricted to 1/4 of the wavelength, preventing sufficiently short sampling intervals
Solution Approach 1:
The patent introduces an optical modulator as an intermediary component that adds a modulation signal to the laser light reflected by the movable mirror. This modulation signal serves as a new trigger mechanism that is not constrained by the wavelength of the laser light, thereby enabling sampling at intervals shorter than 1/4 of the wavelength while maintaining accurate position detection capability
Solution Approach 2:
The patent changes the parameter used for triggering sampling from the intensity of laser light to a modulation signal with a frequency higher than the reciprocal of the desired sampling interval. This parameter change allows the sampling interval to be independently controlled and reduced below the traditional 1/4 wavelength limit
2Measurement precision
If the sampling interval of measurement light is reduced to enhance interferogram resolution, then spectral information resolution improves, but the band of measurable wavelengths cannot be sufficiently widened
Solution Approach 1:
The patent makes the sampling interval dynamic by controlling it based on the modulation signal frequency rather than being fixed by laser wavelength. This allows the system to adaptively adjust the sampling interval to achieve high resolution for short-wavelength measurement light while maintaining the capability to measure across a broader wavelength range
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 enables high-resolution spectral information acquisition even with shorter wavelength measurement light, expanding the measurable wavelength range and improving the accuracy of spectroscopic analysis.
Implementation Method 1
The measurement light emitted from the first light source and passing through an object to be measured is split by the beam splitter unit
Implementation Method 2
The part and the remaining part of the measurement light returned to the beam splitter unit are detected as interference light by the first photodetector
Implementation Method 3
an optical modulator configured to add a second modulation signal to the laser light
Data Source
AI summary
An optical device includes: a first optical system; and a second optical system. The first optical system includes a first light splitting device configured to split measurement light emitted from a first light source into a first measurement light and a second measurement light and then mix the split measurement light, a first mirror configured to add a first modulation signal by being moved in an entering direction of the first measurement light and reflecting the first measurement light, a second mirror configured to reflect the second measurement light, and a first light receiving device configured to receive the measurement light including a sample-derived signal and the first modulation signal and output a first light receiving signal. The second optical system includes a second light source configured to emit laser light, an optical modulator configured to add a second modulation signal to the laser light, and a second light receiving device configured to receive the laser light including a displacement signal generated by reflection on the first mirror and the second modulation signal and output a second light receiving signal.