Optical properties of metallic quantum wells

The authors model the optical properties of metallic quantum wells with thicknesses in the range of a few nanometers. A simple picture that includes only single electron transitions predicts strong absorption lines at frequencies associated with allowed interband transitions. This strong absorption feature can be in the near infrared for metal films several monolayers thick. The model is extended to include collective electron interactions by solving simultaneously Schroedinger´s and Poisson´s equations. It is found that the single electron picture does not change appreciably for frequencies above the bulk plasma frequency of the metal. For frequencies at or below the plasma frequency, however, the absorption is reduced in strength and becomes nearly featureless