A Caltech Library Service

Beam Misalignments and Fluid Velocities in Laser-Induced Thermal Acoustics

Schlamp, Stefan and Cummings, Eric B. and Hornung, Hans G. (1999) Beam Misalignments and Fluid Velocities in Laser-Induced Thermal Acoustics. Applied Optics, 38 (27). pp. 5724-5733. ISSN 0003-6935.

See Usage Policy.


Use this Persistent URL to link to this item:


Beam misalignments and bulk fluid velocities can influence the time history and intensity of laser-induced thermal acoustics (LITA) signals. A closed-form analytic expression for LITA signals incorporating these effects is derived, allowing the magnitude of beam misalignment and velocity to be inferred from the signal shape. It is demonstrated how instantaneous, nonintrusive, and remote measurement of sound speed and velocity (Mach number) can be inferred simultaneously from homodyne-detected LITA signals. The effects of different forms of beam misalignment are explored experimentally and compared with theory, with good agreement, allowing the amount of misalignment to be measured from the LITA signal. This capability could be used to correct experimental misalignments and account for the effects of misalignment in other LITA measurements. It is shown that small beam misalignments have no influence on the accuracy or repeatability of sound speed measurements with LITA.

Item Type:Article
Related URLs:
URLURL TypeDescription
Hornung, Hans G.0000-0002-4903-8419
Additional Information:© Copyright 1999 Optical Society of America. Received 1 April 1999; revised manuscript received 21 June 1999. The authors acknowledge Thomas H. Sobota of Advanced Projects Research, Incorporated, for providing the motivation for understanding and characterizing the effects of beam misalignments and fluid velocity on the LITA signal. This research was supported by Advanced Projects Research, Incorporated, and the U.S. Air Force Research Laboratory at Edwards Air Force Base.
Subject Keywords:Four-wave mixing; Diffraction gratings; Metrology
Issue or Number:27
Record Number:CaltechAUTHORS:SCHLao99
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:7689
Deposited By: Archive Administrator
Deposited On:22 Mar 2007
Last Modified:22 Nov 2019 09:58

Repository Staff Only: item control page