Terahertz Spectroscopy and Brewster Angle Reflection Imaging of Acoustic Tiles

Figure 4

Spectral content transmission image (0.01 THz to 0.10 THz) of tile sample “A1-8” with air-filled voids taken at a grid resolution of 2 mm. Transmitted energy is shown colored from blue (low transmission) to red (high transmission) with the scale shown in arbitrary units. Both circular voids are discernible. The large and small cylindrical voids of this sample are 2.2 cm and 0.75 cm in diameter, respectively, with a separation of 0.8 cm. The transmission cut-off on the right hand side of the image was caused by metal apparatus used to hold the tile sample.