Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Broaband THz aqueous blackbody calibration source



Charles Dietlein, Zoya Popovic, Erich N. Grossman


We describe a broadband calibration source for the millimeter-wave to terahertz (THz) frequency range, the Aqueous Blackbody Calibration (ABC) source. The blackbody in this design is a body of water, which is extremely absorptive at these frequencies, held by an expanded polystyrene (EPS) holder in a very specific shape, and kept at a uniform known temperature. The undesirable reflectance at the interfaces between the water and the walls of the EPS container is significantly reduced by the use of an "optical trap" geometry. The shape of the custom-molded container is designed so that all radiation incident within the entrance aperture and solid angle of the source undergoes two TE and two TM 45 degree reflections off the water-EPS interface. This ensures an effective emissivity >98.5 % over the operating band, and has been verified by measurements of EPS transmittance and geometric optics simulation over the entire band. In addition, the effective reflectance of the source is characterized at selected frequencies within the 0.1-2.0THz range.
Proceedings Title
Proc., SPIE
Conference Dates
April 9-13, 2007
Conference Location
Orlando, FL, USA
Conference Title
SPIE - The International Society for Optical Engineering, Defense & Security Symposium


bolometer, millimeter-wave, terahertz


Dietlein, C. , Popovic, Z. and Grossman, E. (2007), Broaband THz aqueous blackbody calibration source, Proc., SPIE, Orlando, FL, USA, [online], (Accessed April 25, 2024)
Created April 8, 2007, Updated October 12, 2021