title: Extinction coefficient
text: # Extinction coefficient
  
  Extinction coefficient refers to several different measures of the absorption of light in a medium:
  
  * Attenuation coefficient, sometimes called "extinction coefficient" in meteorology or climatology
     * Mass extinction coefficient, how strongly a substance absorbs light at a given wavelength, per mass density
     * Molar extinction coefficient, how strongly a substance absorbs light at a given wavelength, per molar concentration
  * Optical extinction coefficient, the imaginary part of the complex index of refraction
  