Schematic Presentation of Test Equipment:

 

The N₂ Pulse Laser:

• generates a wide bandwidth of surface acoustic waves,
• is non-contact,
• can be focused on a small area,
• can be positioned very accurately.

Laser Acoustic Test Sequence:

             

A short laser pulse                  The wave propagates            A piezoelectric wide-band generates the surface              through the material.           detector picks up
acoustic wave impulse.                                                      the acoustic impulse.

Process description:

           Signal              Fourier Transformation      Dispersion Curve

Data Acquisition and Analysis Software:

Program window at the start of measurement:

Program window while the measurement is in progress:

Program window at the end of measurement:

(Dispersion curve is fitted for substrate and film Young's Modulus)