Laser Interferometer Optical Axis Alignment
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Solution Overview
Problem
Laser interferometers face a decrease in signal-to-noise ratio and measurement accuracy due to interference fringes caused by non-parallel optical axes in non-coaxial optical systems, leading to destabilization of laser oscillation and reduced accuracy in vibration velocity measurement.
Innovation Solution
A laser interferometer with an optical interference unit that includes a laser source, light modulator, light receiving element, and angular deviation detection system, which adjusts the optical axis by detecting positional and angular deviations using a first aperture element and instruction unit to align the object light and reference light axes, preventing interference fringes and maintaining signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a non-coaxial optical system is used to suppress return light, then laser oscillation stability is improved, but interference fringes occur due to non-parallel optical axes causing decrease in S/N ratio
Solution Approach 1:
The patent introduces an adjustable optical axis alignment mechanism that allows dynamic adjustment of the optical axes during system setup and operation. This enables the system to adapt to different measurement conditions while maintaining optimal alignment, resolving the contradiction between using a non-coaxial system for stability and requiring parallel axes for high S/N ratio
Solution Approach 2:
The patent employs detection means to monitor the alignment state of optical axes and provides feedback for adjustment. This feedback mechanism allows operators to optimize the optical alignment to prevent interference fringes while maintaining the benefits of the non-coaxial system configuration, thereby improving measurement precision without sacrificing oscillation stability
2Measurement precision
If optical axes are aligned to be parallel to prevent interference fringes, then S/N ratio is improved, but the ability to suppress return light is reduced
Solution Approach 1:
The system allows dynamic switching between different optical configurations. When high S/N ratio is prioritized, optical axes can be aligned parallel; when return light suppression is prioritized, the non-coaxial configuration can be maintained. This dynamic adaptability resolves the contradiction between the two opposing requirements
Solution Approach 2:
The patent modifies optical parameters (such as angle between axes, position of optical components) to achieve optimal balance between return light suppression and interference fringe prevention. By adjusting these parameters, the system can optimize performance for different measurement scenarios, resolving the contradiction between S/N ratio and oscillation stability
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
The solution effectively prevents the decrease in signal-to-noise ratio and enhances measurement accuracy by aligning the optical axes, ensuring stable laser oscillation and precise vibration velocity measurement.
Implementation Method 1
a light modulator configured to modulate a frequency of the laser beam to generate reference light
Implementation Method 2
a light receiving element configured to receive object light generated in response to irradiation of an object with the laser beam, and the reference light to output a received light signal
Implementation Method 3
a first aperture element disposed on a light path through which the object light and the reference light enter the light receiving element, and configured to detect a positional deviation of an optical axis of the object light from an optical axis of the reference light
Data Source
AI summary
A laser interferometer includes an optical interference unit as a non-coaxial optical system including a laser source for emitting a laser beam, a light modulator for modulating a frequency of the laser beam to generate reference light, a light receiving element for receiving object light generated in response to irradiation of an object with the laser beam, and the reference light to output a received light signal, a first aperture element disposed on a light path entering the light receiving element, and for detecting a positional deviation of an optical axis of the object light from an optical axis of the reference light, and an angular deviation detection unit for detecting an angular deviation of the optical axis of the object light from the optical axis of the reference light based on the received light signal, and an instruction unit for issuing an instruction to change a relative arrangement between the optical interference unit and the object based on a detection result of the positional deviation and a detection result of the angular deviation.