Optical Resonator TM TE Mode Differential Sensing
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Solution Overview
Problem
Optical sensing devices based on interferometers and resonators face challenges in distinguishing changes in samples from thermal fluctuations, leading to noise and reduced detection sensitivity due to temperature sensitivity of transverse magnetic (TM) and transverse electric (TE) modes.
Innovation Solution
Implementing optical sensing devices that utilize spatially overlapping TM and TE modes, where the difference in resonance wavelengths or phase shifts between these modes is measured to isolate changes in samples from thermal noise, allowing for temperature-insensitive detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical sensing devices use single mode (TM or TE) for detection, then detection sensitivity to sample changes is achieved, but thermal noise and temperature sensitivity increase
Solution Approach 1:
The patent combines TM and TE modes in a single optical resonator system, where both modes are excited and their resonance frequencies are measured simultaneously. This merging allows the system to exploit the differential response between modes to cancel thermal noise while maintaining sensitivity to sample changes.
Solution Approach 2:
The patent introduces a differential measurement approach where the difference between TM and TE resonance frequencies serves as an intermediary signal. This differential signal acts as a mediator that is sensitive to sample changes but insensitive to temperature fluctuations, effectively separating the useful signal from thermal noise.
2Object-affected harmful factors
If temperature-insensitive detection is achieved through differential mode measurement, then thermal noise is reduced, but device complexity increases
Solution Approach 1:
The optical resonator is designed to simultaneously support and excite both TM and TE modes using a single laser source and detection system. This multi-functionality allows the device to perform temperature-insensitive differential measurement without requiring separate sensing systems, thereby limiting the increase in device complexity.
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 significantly reduces thermal noise, enhancing detection sensitivity and achieving low detection limits for changes in samples by canceling out temperature-induced effects on the differential frequency between TM and TE modes, thereby improving the accuracy of measurements.
Implementation Method 1
an optical resonator in an optical path of the laser probe beam to receive light of the laser probe beam in a transverse magnetic (TM) mode and a transverse electric (TE) mode and to support both TM and TE optical modes
Implementation Method 2
The optical resonator is located adjacent to or in contact with a sample to cause optical interaction between the sample and the light in the TM and TE optical modes
Implementation Method 3
a detection unit that is coupled to the optical resonator to detect a shift in a difference between a first resonance wavelength of a TE optical mode and a second resonance wavelength of a TM optical mode
Data Source
AI summary
Techniques and devices based on transverse magnetic (TM) and transverse electric (TE) modes in an optical resonator or interferometer to provide sensitive optical detection with insensitivity to a change in temperature. A shift in a difference between a first resonance wavelength of a TE optical mode and a second resonance wavelength of a TM optical mode is measured to measure a change in a sample that is in optical interaction with the optical resonator or interferometer. For example, the detected shift can be used to measure a change in a refractive index of the sample.