The laser-dual-focus flow velocimeter
Abstract
The use of a low cost rotating radial diffraction grating as a beam splitting frequency shifter for operation in laser Doppler velocimeter systems is discussed. A high efficiency phase grating is used that can be exposed to high power laser beams. A compact optical design is described having a grating disc with a diameter of 35 mm and a line density of 166 line pairs per mm. Several optical arrangements, operating as well in the fringe mode as in the reference beam mode, are studied. The advantages of these arrangements are the simple set-up and the ease of optical alignment, which become significant for the two and three component systems.
- Publication:
-
In AGARD Appl. of Non-Intrusive Instr. in Fluid Flow Res. 9 p (SEE N77-11221 02-31
- Pub Date:
- May 1976
- Bibcode:
- 1976anii.agarR....S
- Keywords:
-
- Frequency Shift;
- Gratings (Spectra);
- Laser Doppler Velocimeters;
- Backscattering;
- Flow Measurement;
- Laser Modes;
- Velocity Measurement;
- Instrumentation and Photography