Terahertz reflectivities of metal-coated mirrors

Abstract

Terahertz (THz) reflectivities of a variety of metal-coated mirrors were measured. Gold, silver, and aluminum coatings were tested and compared. It was found that all types of optical metal-coated mirrors perform equally well as THz reflectors.

Enabling simultaneous cooling and data transmission in the terahertz band for board-to-board communications

“…The reflectivity of a metal surface is near unity in the 0.1-10 THz band due to high electrical conductivity. Thus, well-polished metal surfaces or metal coating mirrors could act as THz reflectors [31,32]. The most commonly used metals for this purpose are gold, silver, copper and aluminum.…”

“…The thickness of a metal or metal coating should also be taken into account. In order to achieve maximum reflectivity for a given metal, the thickness of the metal layer must be at least two penetration depths, δ at the frequency of the incident beam [32]. Penetration depth is the attenuation length of exponentially decaying electromagnetic field when the wave is incident on a conductor, that is,…”

CEBAF Upgrade Bunch Length Measurements

“…The resistivity of gold at room temperature is 2.271 × 10 −2 µΩm and the wave length of interest is 100 µm for obtaining coherent synchrotron radiation, so the reflectivity of a mirror is about 99. 45. Gold coated mirrors are very good to use in the infrared and we chose to use gold coated mirrors in the real time interferometer (RTI) experiment.…”

“…reflectivty and the SR power is expected to be less by about 7% because fourteen mirrors are used. According to [45], different metal coated mirrors were tested and compared. It was found that gold, silver, and aluminum coatings perform equally in the THz regime, so there is no reason to change the mirrors in order to decrease the loss from the mirrors.…”

Design of optical components for terahertz/sub-terahertz imaging systems

“…Metallic mirrors are known to be achromatic and to show a very high efficiency, as actual metals in the THz range behave almost as ideal conductors [3]. Nevertheless, reflecting and focusing the mirrors are very sensitive to any misalignment and they do not work properly off the axis.…”