High Resolution Imaging
By focusing the broadband terahertz beam with a short focal length lens, spatial resolution down to 200 microns can be achieved.
In this example, high resolution printing is legible on a U.S. $20 bill.
Higher resolution images can be obtained by near field imaging (using a small aperture just in front of the object) or in conjunction with an atomic force microscope (AFM). In this second case the terahertz beam illuminates the sample while the AFM is modulated above the sample.