Optical Absorption and Fluorescence of Nanomaterials
This chapter focuses on linear optical absorption and luminescence and explores extended tutorial part addressing basics of the light emission and absorption mechanisms that will help students and young researchers to better understand the subject. Absorption is the process by which a photon is absorbed by the atom, causing an electron to jump from a lower energy level to a higher one. The frequency dependence of the absorption coefficient is determined by various physical processes which govern the optical properties of nanomaterials. The phenomena which involve absorption of light energy and subsequent emission of secondary light are classified as luminescence. The linear optical properties like absorption and scattering of small spherical metal particles accounting for the surface plasmon resonance were explained theoretically by G. Mie. Via surface enhanced infrared absorption the field enhancement should enable the detection of vibrational fingerprints of single molecules on nanoantennas by studying light scattering with apertureless scanning near field microscopy.