Anomalous dispersion - ijobunsan (English spelling)

Japanese: 異常分散 - いじょうぶんさん（英語表記）anomalous dispersion

The refractive index of a transparent material generally tends to decrease monotonically as the wavelength of light increases, but when the wavelength of light approaches the wavelength at which the material resonates, a sudden change in the refractive index occurs. That is, as the wavelength of light increases and approaches the wavelength from the short side, the refractive index decreases suddenly, increases discontinuously at that wavelength, and then decreases again gradually as the wavelength becomes longer, returning to the normal value. This phenomenon is called anomalous dispersion. In the case of sound waves, this refers to the phenomenon in which the speed of sound does not increase monotonically with increasing frequency, and is closely related to the absorption of sound waves by a medium.

Source: Encyclopaedia Britannica Concise Encyclopedia About Encyclopaedia Britannica Concise Encyclopedia Information

Japanese:

透明な物質の屈折率は，光の波長が長くなるに従って一般に単調に減少する傾向にあるが，その物質が共鳴吸収を起す波長に光の波長が近づくと，屈折率に急激な変化が起る。すなわち光の波長が増大して短い側からその波長のところに近づくと，屈折率は急激に減少し，その波長のところで不連続的に急増したのち，波長がさらに長くなると再び次第に減少して正常の値に戻る。この現象を異常分散という。音波の場合には振動数の増加とともに音速が単調増加を示さない現象をいい，媒質による音波の吸収と密接な関係がある。

出典　ブリタニカ国際大百科事典小項目事典ブリタニカ国際大百科事典小項目事典について　情報

<<: Hemoglobinopathy - Hemoglobinopathy

>>: Anomalous specific heat