University of Strathclyde

Theodosia Stratoudaki 

Laser ultrasonics (LU) is a technique that uses lasers to excite and detect ultrasound. It is delivered remotely, without couplant, addressing delivery challenges of the industry related to inspection under extreme environments and places of restricted access. Laser Induced Phased Arrays (LIPAs) provide superior ultrasonic imaging than conventional LU techniques by successfully addressing the poor signal-to-noise ratio (SNR) usually associated with LU, especially for the non destructive regime (i.e. where the generation laser power is below the damage threshold of the material). We were the first to demonstrate the proof-of-concept of LIPAs for NDE and we are now able to offer cross sectional and volumetric (3D) ultrasonic imaging using all-optically acquired data. Our LIPA proved the principle but is currently too slow for real-world imaging problems and its full potential has yet to be reached. The aspiration for Adaptive LIPAs is to deliver real-time data acquisition and this is the overall aim of the proposed PhD. It can be realised by developing novel instrumentation for Laser Ultrasonics as as introducing a fundamental change in the data acquisition methodology for ultrasonic imaging using phased arrays. 

The core objectives of the PhD study will be: 

  • development of optimised LIPA instrumentation for fast data acquisition with improved SNR; 
  • real-time LIPA operation with on-the-fly adaptation of data acquisition for optimised inspection; 
  • demonstration of the potential of the technique in a variety of industrial applications. 

The novel instrumentation will include the use of spatial laser beam modification (laser beam patterns) to manipulate (steer and focus) the generated ultrasound and similar techniques will be used for laser ultrasonic detection. Following development, a new system of adaptive LIPAs will be designed, built, and tested on samples provided by the industry.  

During the PhD, the student will become a member of a dynamic, supportive and collaborative research team within Strathclyde’s Centre for Ultrasonic Engineering. The student will also collaborate with researchers from the Universities of Nottingham and Bristol and industrial partners from safety critical applications related to transportation and power generation. In addition, this project is directly applicable to industrial sectors such as additive manufacturing, space, aerospace, nuclear and bio-medical.