There has been a great interest in measuring optical rotatory power (ORP) and circular dichroism (CD), which are differences of refractive index and absorption coefficient between left and right circularly polarized lights because these provide valuable information on (1) asymmetry and/or dissymmetry of molecular and crystal structure and (2) spatial dispersion of the atoms positions.

However, conventional optical apparatuses such as polarimeters and CD spectrophotometers are insufficient for accurate measurements of ORP and CD except in an optic-axis direction because the observed ORP and CD signals are overwhelmed by optical anisotropy signals such as linear birefringence (LB) and linear dichroism (LD).

In 1983, the high accuracy universal polarimeter (HAUP) method, which enables us to simultaneously measure ORP and LB of transparent anisotropic medium, has been developed by Kobayashi [1]. Subsequently, the measurement principle of HAUP was extended to measure simultaneously CD and LD of absorbent anisotropic media [2-3]. Moreover, the HAUP apparatus was generalized using an Xe lamp and a monochromator, which could continuously obtain UV and visible region spectra (300-680 nm).

Following are the research theme we mainly conducted. (Others: Look at [4-7].)


(1) Relationship between absolute structure and optical rotatory power in organic and inorganic chiral crystals

(2) Measurement of Faraday rotation and Magnetic CD along perpendicular to the optic axis

(3) Symmetry breaking research on Copper oxide high-temperature superconductors

[1] J. Kobayashi et al., J. Appl. Cryst., 16, 204 1983.
[2] J. Kobayashi, T. Asahi et al., Phys. Rev. B, 53, 11784, 1996.
[3] M. Tanaka, T. Asahi et al., J. Phys. D: Appl. Phys., 45, 175303, 2012.
[4] K. Ishikawa, T. Asahi et al., Chem. Comm., 48, 6031, 2012.
[5] Y. Ishida, K. Nakagawa, T. Asahi et al., JACS, 135, 6407, 2013.
[6] K. Nakagawa, T. Asahi et al., Chem. Comm., 50, 15086, 2014.
[7] T. Asahi, Y. Ogino, K. Nakagawa, Chemical Industry, 66, 97, 2015.