Capacitance cells have been designed and constructed for measuring the low-frequency dielectric constant of nonmetallic samples such as optical materials. One equipment covers the 80–300-K temperature range and the other, the 300–500-K range. Data are reported for optical materials CaF2, KCl, ZnS, and MgF2 (measured parallel to c axis) and a reference material: Teflon sheet. Only Teflon has been measured in both temperature ranges. A special feature of the equipment is that the dielectric cell can easily be replaced by a cell adapted to measure the linear thermal expansion of appropriate samples through the same temperature ranges, and these measurements permit improved determinations of the temperature coefficient of the dielectric constant.
© 1984 Optical Society of America
James Steve Browder, Max E. McCurry, and Stanley S. Ballard, "Dielectric measurements of optical materials in the 80–500-K range, with a three-terminal capacitance cell," Appl. Opt. 23, 537-540 (1984)