Illustrations
1.1 The terahertz region of the spectrum lies between microwaves and
infrared, and is characterized by a tree-space wavelength between 30
microns and 3 millimeters. The photon energy corresponding to квТ
at room temperature, 40 meV, is equivalent to a frequency of about
10 THz................................... 2
2.1 One of the first images acquired using a time-domain system, adapted
from the original paper by Hu and Nuss. This shows a transmission
image of a semiconductor integrated circuit, through the black epoxy
package which is transparent to terahertz radiation. The metallization
inside the package is clearly visible, as is the semiconductor wafer in
the center. The spatial resolution of this image is roughly 250
microns. The inset shows an optical image of the sample........ 7