Figure 4
From: Non-contact ultrasonic inspection by Gas-Coupled Laser Acoustic Detection (GCLAD)

Signal from a surface wave propagating in the component as in the scheme of Fig. 3, refracted in air and subsequently detected by the GCLAD device.
From: Non-contact ultrasonic inspection by Gas-Coupled Laser Acoustic Detection (GCLAD)

Signal from a surface wave propagating in the component as in the scheme of Fig. 3, refracted in air and subsequently detected by the GCLAD device.