Retrofittable antireflection coatings for T-rays

Abstract

T-ray reflection loss at a window's surface is reduced by means of a quarter-wave antireflection coating. Because T-ray wavelengths are much longer than visible wavelengths, the antireflection layer for T-rays is much larger than the layers typically used in optics. This creates an interesting opportunity for retrofittable antireflection layers. In the experiment, an antireflection coating made from ordinary polyethylene sheets is pressed onto the surfaces of a silicon window in the way that rapid replacement of the rettroflttable coating is possible. Measured by terahertz time-domain spectroscopy (THz-TDS), the coated window shows enhancement of the transmittance within a range of T-ray frequencies. © 2007 Wiley Periodicals, Inc.