Detection of laser induced dielectric breakdown in water using a laser doppler vibrometer
2010 (English)In: Central European Journal of Physics, ISSN 1895-1082, E-ISSN 1644-3608, Vol. 8, no 2, 235-241 p.Article in journal (Refereed) Published
This study is focused on exploring the feasibility of an all-optic surface scanning method in determining the size and position of a submerged, laser generated, optoacoustic source. The optoacoustic effect was here generated when the absorption of a short electromagnetic pulse in matter caused a dielectric breakdown, a plasma emission flash and a subsequent acoustic wave. In the experiment, a laser pulse with l = 1064 nm and 12 ns pulse length was aimed at a volume of deionized water. When the laser beam was focused by a f = 16 mm lens, a single dielectric breakdown spot occurred. When a f = 40 mm was used several breakdowns in a row were induced. The breakdowns were photographed using a double shutter camera. The acoustic wave generated by the dielectric breakdowns were detected at a point on the water surface using a laser Doppler vibrometer (LDV). First, the LDV signal was used to calculate the speed of sound with an accuracy of 10 m/s. Secondly, the location and length of the dielectric breakdown was calculated with an accuracy of 1 mm. The calculated position matched the breakdown location recorded by a camera. The results show that it is possible to use LDV surface measurements from a single spot to determine both the position and length of the OA source as well as the speed of sound in the medium. Furthermore, the LDV measurements also show a secondary peak that originates from the OA source. To unravel the origin and properties of this interesting feature, further investigations are necessary.
Place, publisher, year, edition, pages
2010. Vol. 8, no 2, 235-241 p.
Research subject Industrial Electronics; Experimental Mechanics; Medical Engineering for Healthcare
IdentifiersURN: urn:nbn:se:ltu:diva-7456DOI: 10.2478/s11534-009-0122-9Local ID: 5d630bd0-9d45-11de-a77c-000ea68e967bOAI: oai:DiVA.org:ltu-7456DiVA: diva2:980345
Validerad; 2010; 20090909 (ysko)2016-09-292016-09-29Bibliographically approved