Spectrometer Interferometer Sampling Beyond Laser Wavelength Limits
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Solution Overview
Problem
Existing optical devices face limitations in achieving high resolution spectral information due to the restriction that the minimum interval between feature points depends on the wavelength of laser light, making it difficult to sample measurement light at sufficiently short intervals, thereby limiting the resolution of interferograms and spectral information.
Innovation Solution
Incorporating a second light source emitting laser light with a different wavelength, a light splitter to split and mix measurement and laser light beams, a movable mirror for modulation, and photodetectors to capture signals, along with a signal generator and calculation device for Fourier transform, enabling precise determination of the movable mirror's position and enhancing spectral information resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the position of the movable mirror is measured based on feature points of laser light interference, then the position can be determined, but the sampling interval cannot be shortened below 1/4 of the laser wavelength
Solution Approach 1:
The patent introduces laser light as an intermediary measurement signal that does not interfere with the measurement light. The laser light serves as a mediator to track mirror position independently, allowing the measurement light to be sampled at any interval without being constrained by the laser wavelength. This resolves the contradiction by decoupling the position measurement function from the spectral measurement function.
Solution Approach 2:
The patent changes the parameter being measured for mirror position from the measurement light (which has wavelength constraints) to laser light (which can be measured at higher frequencies). By changing the measurement parameter to laser light with suitable properties, the sampling rate limitation is overcome while maintaining position measurement accuracy.
2Measurement precision
If the sampling interval of measurement light is limited by laser wavelength, then position measurement is achievable, but spectral information resolution cannot be sufficiently enhanced
Solution Approach 1:
The laser light acts as an intermediary that provides continuous position information without limiting the sampling rate of measurement light. This allows the interferogram to be sampled at sufficiently short intervals to achieve high spectral resolution, while the laser simultaneously provides the necessary position reference for accurate spectral analysis.
Solution Approach 2:
The patent segments the measurement system into two independent functions: laser light for position measurement and measurement light for spectral measurement. This segmentation allows each function to operate independently with optimal parameters, enabling high sampling rates for spectral resolution without being constrained by laser wavelength.
3Adaptability or versatility
If a single light source is used, then the device is simpler, but the wavelength range cannot be sufficiently widened for short-wavelength measurement light
Solution Approach 1:
The patent implements multi-functionality by having the beam splitter unit serve dual purposes: splitting measurement light for spectral analysis and splitting laser light for position measurement. This universal use of optical components allows wavelength range expansion without proportionally increasing device complexity, as the same hardware infrastructure supports multiple functions.
Solution Approach 2:
The laser light serves as an intermediary that enables the system to handle short-wavelength measurement light by providing a separate, longer-wavelength reference that does not interfere with the measurement. This intermediary approach allows the system to extend its effective wavelength range capability without requiring additional specialized components for each wavelength.
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 configuration allows for high-resolution spectral information acquisition by reducing sampling intervals and expanding the wavelength range, improving the accuracy of spectroscopic analysis.
Implementation Method 1
the beam splitter unit, the movable mirror, and the fixed mirror constitute an interference optical system that measurement light and laser light separately enter
Implementation Method 2
a first mirror configured to move with respect to the light splitter, and reflect the first beam of the measurement light and the first laser light beam, thereby adding a first modulation signal to the first beam of the measurement light and adding a displacement signal to the first laser light beam
Implementation Method 3
a first photodetector configured to receive the measurement light including the first modulation signal and a sample-derived signal that is generated by interaction between the measurement light and a sample, and to output a first light reception signal
Implementation Method 4
an optical modulator driven based on a drive signal and configured to add a second modulation signal to the second laser light beam after separation by the first color separator
Implementation Method 5
a first color separator configured to separate the second beam of the measurement light from the second laser light beam based on a difference in wavelength
Implementation Method 6
By subjecting the interferogram to Fourier transform, spectral information of the object to be measured can be obtained
Data Source
AI summary
An optical device includes: a second light source configured to emit laser light having a wavelength different from that of measurement light emitted from a first light source; a light splitter; a first mirror configured to add a first modulation signal to the measurement light and add a displacement signal to the laser light; a second mirror configured to reflect a second beam of the measurement light; a first color separator configured to separate the second beam of the measurement light from a second laser light beam based on a difference in wavelength; an optical modulator driven based on a drive signal and configured to add a second modulation signal to the second laser light beam after the separation; a first photodetector configured to receive the measurement light including a sample-derived signal and the first modulation signal; and a second photodetector configured to receive the laser light including the displacement signal and the second modulation signal.