Optical Absorption and Emission

R.J. Beach, Michelle D. Shinn, L. Davis +2 more

Cheng Guo, Shanhui Fan

Unitary control changes the optical absorption and emission of an object by transforming the external modes. We answer two basic questions: Given an object, what absorptivity, emissivity, and their difference are attainable via unitary control? How to obtain given absorptivity, emissivity, and their difference? We show that both questions can be answered using the mathematics of majorization.

V. I. Gavrilenko, Volodymyr S. Ovechko

Methods of optical spectroscopy are widely used to study optical properties of materials. This area includes different methods of both linear and nonlinear optics. This chapter focuses on linear optical absorption and luminescence. It includes extended tutorial part addressing basics of the light emission and absorption mechanisms that will help students and young researchers to better understand the subject. The chapter presents a brief overview of basic physics that governs absorption and luminescence of light in materials. It then presents a classic picture of the optical absorption of materials. In order to make a next step and to get a quantum mechanical picture of light interaction with materials it is instructive to start with the interaction of an electromagnetic wave with an atom. There are three basic processes that are responsible for a formation of atomic spectra, i.e. spontaneous emission, stimulated emission, and absorption.

Hans Joachim Eichler, Jürgen Eichler, Oliver Lux

Mansoor Sheik‐Bahae, Jackson L. Kock

The effects of amplified spontaneous emission (ASE) as well as absorption saturation in cryogenic optical refrigeration in rare-earth doped materials are analyzed theoretically. It is seen that ASE may pose a limitation on power scaling under strong feedback conditions (i.e. in high finesse pump circulator cavities). Absorption saturation may have similar effect depending on the value of the background absorption.