Levorotatory

…Optical activity is sometimes used synonymously with optical activity because it is closely related to circular dichroism, another type of optical activity, through the Kramers-Kronig relationship (Kramers' law), and the two are mutually exclusive. When observed toward traveling light, if the plane of polarization of linearly polarized light rotates to the right (clockwise direction) after passing through an optically active substance (also called an optically active substance), it is called dextrorotatory, and if it rotates to the left, it is called levorotatory. This is explained as occurring because (1) linear polarization is represented as the sum (superposition) of right-handed circularly polarized light and left-handed circularly polarized light, and (2) the refractive index of the optically active substance is different for these two types of circular polarization. …

*Some of the terminology explanations that mention "levorotatory" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…他の光学活性の一つである円偏光二色性とクラマース=クローニヒの関係(クラマースの法則)で密接に関係づけられ，両者は互いに裏腹の関係にあるので，旋光性を光学活性と同義に用いることもある。進む光に向かって観測するとき，直線偏光の偏光面が旋光性物質(光学活性物質ともいう)を通過後に，右(時計の針の回る方向)に回る場合を右旋性dextrorotatory，左に回る場合を左旋性levorotatoryという。これは，(1)直線偏光が，右回りの右円偏光と左回りの左円偏光の和(重ね合せ)で表され，しかも(2)この二つの円偏光に対して旋光性物質の屈折率が異なるために起こると説明されている。…

※「levorotatory」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報