Laser Ultrasonic Sensors with Near PZT-Transducer. DURIP99
Abstract
Several key milestones have been reached in our investigation of photorefractive-based pulsed laser interferometry. The first issue involves the response time of photorefractive crystals under pulse illumination. The laser system is capable of producing a "top-hat" laser pulse with a maximum duration of 100 micro s. This means that the crystal response time must be less than 60-80 micro s such that the grating can be formed during the first part of the laser pulse and the ultrasonic signal can be detected during the final 10-20 micro s. It was found that the response time of the GaAs was sufficiently shorter than 60 micro s such that substantial two-wave mixing gain could be observed even within the first 10-20 micro s of the pulse. Next, surface acoustic waves have been detected using the pulsed interferometer. Although only moderate signal-to-noise ratio has been achieved to date, several modifications of the system are currently underway that we hope will lead to substantial improvements.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2000
- Accession Number
- ADA381618
Entities
People
- Jan D. Achenbach
- Sridhar Krishnaswamy
Organizations
- Northwestern University