Metrology device with wavelength-frequency multiplexing
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Solution Overview
Problem
Conventional spectroscopic metrology systems require time-consuming mechanical movements and precise alignments to process multiple wavelengths, leading to reduced throughput and sensitivity to mechanical vibrations.
Innovation Solution
An optical metrology device uses a wavelength modulator with crossed polarizers and an electro-optical modulator to multiplex wavelengths and frequencies without moving parts, enabling simultaneous modulation and data collection through computer-controlled electro-optics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mechanical movements and precise alignments are used to process multiple wavelengths, then wavelength separation and detection are achieved, but throughput is reduced and sensitivity to mechanical vibrations increases
Solution Approach 1:
The patent replaces mechanical wavelength separation systems (gratings, prisms, moving mirrors) with an electro-optical modulator that uses electrical signals to modulate different wavelengths at different frequencies. This substitution eliminates mechanical movements and alignments while enabling simultaneous processing of multiple wavelengths, thereby resolving the contradiction between measurement precision and productivity
Solution Approach 2:
The patent employs periodic modulation of wavelengths at distinct frequencies through the electro-optical modulator. Each wavelength is modulated at a unique frequency, allowing simultaneous detection of multiple wavelengths through frequency-domain analysis. This periodic action enables high throughput data collection without sacrificing wavelength detection precision
2Measurement precision
If mechanical movements are used to process multiple wavelengths, then spectral analysis is achieved, but sensitivity to mechanical vibrations increases
Solution Approach 1:
The patent substitutes mechanical wavelength processing components with an electro-optical modulator controlled by electrical signals. This replacement eliminates the sensitivity to mechanical vibrations inherent in mechanical systems while maintaining spectral analysis accuracy through frequency-domain multiplexing of wavelengths
Solution Approach 2:
The patent changes the control parameter from mechanical position to electrical frequency. By modulating wavelengths at different frequencies through electrical control rather than mechanical movement, the system achieves vibration resistance while preserving spectral analysis capability
3Loss of information
If time-consuming mechanical movements are used to collect data, then comprehensive spectral data is obtained, but data collection time increases
Solution Approach 1:
The patent enables continuous simultaneous measurement of multiple wavelengths through frequency-domain multiplexing. All wavelengths are measured at the same time rather than sequentially, eliminating the time-consuming mechanical movements required for sequential wavelength processing while maintaining complete spectral data coverage
Solution Approach 2:
By modulating wavelengths at distinct frequencies and detecting them simultaneously through periodic modulation, the patent achieves complete spectral data collection in parallel. This approach dramatically reduces data collection time compared to sequential mechanical scanning while preserving comprehensive spectral information
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 allows for rapid, vibration-resistant data collection and analysis of sample characteristics by multiplexing wavelengths and frequencies, enhancing throughput and reducing mechanical dependencies.
Implementation Method 1
an electro-optical modulator that is disposed between the pair of crossed polarizers and that modulates a polarization state of the light in response to a control signal
Implementation Method 2
an electro-optical modulator, such as a Pockels cell or Faraday rotator, disposed between the polarizers
Implementation Method 3
an electro-optical modulator, such as a Pockels cell or Faraday rotator, disposed between the polarizers
Implementation Method 4
a pair of crossed polarizers and an electro-optical modulator that is disposed between the pair of crossed polarizers
Data Source
AI summary
An optical metrology device collects data in parallel by multiplexing wavelength and associated frequencies using computer control and electro-optics in a wavelength modulator. The wavelength modulator includes a pair of crossed polarizers and an electro-optical modulator, such as a Pockels cell or Faraday rotator, disposed between the polarizers. The electro-optical modulator modulates the polarization state of the light in response to a control signal and produces a different amount of polarization rotation for each wavelength in response to each value of the control signal. The control signal causes the electro-optical modulator to modulate the plurality of wavelengths in the light at different frequencies resulting in the production of a wavelength-frequency multiplex from the wavelength modulator. The effect of the sample on the wavelength-frequency multiplex may be used to determine one or more characteristics of the sample.