A new type of energy-tunable X-ray polarimeter has been developed by introducing a Hirano-Ishikawa-Kikuta's transmission-type X-ray phase retarder into an X-ray polarimeter consisting of Hart-Rodrigues' polarizer and analyzer. By using the new type of polarimeter, simultaneous detections of X-ray linear birefringence and dichroism, and simultaneous detections of X-ray linear triple refraction and trichroism, have been made for the first time. The Kramers-Kronig relation has been confirmed in the absolute scale of dielectric constant between linear birefringence and dichroism (and between linear triple refraction and trichroism), which correspond to the real and imaginary parts of dielectric anisotropy, respectively. Phase shift due to the birefringence (or the triple refraction) has been measured with a precision of 2π 110, 000, which is limited mainly by photon-counting statistics.
