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Nonmechanical transverse scanning laser Doppler velocimeter using wavelength change
Koichi Maru1, Toshiki Fujiwara, Ryusuke Ikeuchi
1Department of Reliability-based Information Systems Engineering, Faculty of Engineering, Kagawa University, Takamatsu, Kagawa, Japan. maru@eng.kagawa-u.ac.jp
Applied Optics
|November 16, 2011
Summary
A novel scanning laser Doppler velocimeter (LDV) without moving parts in the sensor probe was developed. This system achieves transverse scanning using a tunable laser and optical components, demonstrating successful measurement position control.
Area of Science:
- Optical Engineering
- Fluid Dynamics Measurement
- Laser-Based Instrumentation
Background:
- Traditional laser Doppler velocimetry (LDV) systems often require mechanical components for scanning measurement points, which can limit their applicability and introduce inaccuracies.
- The development of non-mechanical scanning techniques is crucial for advancing velocimetry applications in challenging environments or for high-speed measurements.
Purpose of the Study:
- To propose and demonstrate a transverse scanning laser Doppler velocimeter (LDV) that eliminates the need for moving mechanisms within the sensor probe.
- To validate the theoretical principles and experimental feasibility of achieving transverse scanning through wavelength modulation and optical manipulation.
Main Methods:
- A scanning LDV system was designed utilizing a tunable laser source to induce wavelength changes.
- A combination of a diffraction grating and a Dove prism was employed to translate wavelength shifts into transverse positional scanning of the measurement beam.
- Experimental validation was performed using a sensor probe constructed with bulk optical components to demonstrate the transverse scanning capability.
Main Results:
- The experimental setup successfully demonstrated the transverse scanning function of the proposed LDV system.
- A scanning range of 11.3 mm in the vertical direction was achieved by varying the laser wavelength between 1520 nm and 1570 nm.
- The results confirm the feasibility of non-mechanical transverse scanning for LDV applications.
Conclusions:
- The proposed scanning LDV system offers a robust alternative to conventional mechanical scanning methods.
- This non-contact, non-mechanical approach enhances the potential for precise fluid velocity measurements in various scientific and engineering fields.
- The demonstrated transverse scanning capability opens avenues for advanced flow analysis and diagnostics.
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