- Zu'i, F.H. and Shaughnessy, E.J., Some characteristics of a GaAlAs diode laser anemometer for measuring fluid velocity,
CLEO '81. Conference on Lasers and Electro-Optics (papers in summary form only received)
pp. 62 - .
(last updated on 2007/04/06)
Reports on the investigation of the GaAlAs diode laser as a source for laser-Doppler anemometry (LDA). A diode based LDA is described which is compact, lightweight, and has low power requirements. Particular attention has been given to design constraints arising from the short coherence length and fan-shaped output beam of the diode. It is shown that nearly equal path lengths are necessary in a diode based LDA and that beam collimation can be achieved with standard microscope objectives. The performance of the diode based LDA was assessed by comparing it with an identical LDA using a 2-mW He-Ne laser. Both devices were used to measure the axial velocity profile in a laminar pipe flow of water. SNRs for each device were also measured. The results show excellent agreement in the velocity profiles except for points very near the walls where the large dimensions of the diode LDA control volume come into play. The diode based device achieved a SNR of 14.8. This is 34% less than that of the He-Ne device but quite satisfactory for flow measurements
aluminium compounds;anemometers;flow measurement;gallium arsenide;laser velocimeters;pipe flow;semiconductor junction lasers;