Reid Matthew, Fedosejevs R
Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Canada.
Appl Opt. 2006 Apr 20;45(12):2766-72. doi: 10.1364/ao.45.002766.
The far-infrared properties of spruce wood are examined with a terahertz time-domain spectrometer. The solid wood is shown to exhibit both birefringence and diattenuation. The birefringence properties are sufficient for construction of a quarter-wave plate operating at 0.36 THz, and a half-wave plate operating at 0.71 THz. The origin of the birefringence is attributed to preferential fiber orientation within the wood. Similar birefringence is observed in lens paper in which the fibers are preferentially oriented in one direction.
