Matter - light interactions

Lee D and Albrecht A C 1993 On global energy conservation in nonlinear light matter interaction the nonlinear spectroscopies, active and passive Adv. Phys. Chem. 83 43-87... 

Kopelman R, Tan Wand Birnbaum D 1994 Subwavelength spectroscopy, exciton supertips and mesoscopic light-matter interactions J. Lumin. 58 380-7... 

Mortensen, N. A. Xiao, S. Pedersen, J., Liquid infiltrated photonic crystals Enhanced light matter interactions for lab on a chip applications, Microfluid. Nanofluid. 2008, 4, 117 127... 

Freely suspended liquid droplets are characterized by their shape determined by surface tension leading to ideally spherical shape and smooth surface at the subnanometer scale. These properties suggest liquid droplets as optical resonators with extremely high quality factors, limited by material absorption. Liquid microdroplets have found a wide range of applications for cavity-enhanced spectroscopy and in analytical chemistry, where small volumes and a container-free environment is required for example for protein crystallization investigations. This chapter reviews the basic physics and technical implementations of light-matter interactions in liquid-droplet optical cavities. 

There are three basic processes of light-matter interaction that can induce transfer of an electron between two quantised energy states ... 

Fig. 1.1. Position of fluorescence and phosphorescence in the frame of light-matter interactions.

Figure 2.5 Descriptions of different light-matter interaction processes (a) absorption (b) spontaneous emission (c) stimulated emission.

Since our system is in equilibrium, the number of absorption transitions i f per unit time must be equal to the number of emission transitions / / per unit time. Considering that the light-matter interaction processes described in Chapter 2 (Figure 2.5) are taking place, in equilibrium the rate of absorption must be equal to the rate of (stimulated and spontaneous) emission. That is ... 

Nonlinear light-matter interactions have been successfully applied to create new visualization contrast mechanisms for optical microscopy. Nonlinear optical microscopy employs femtosecond and picosecond lasers to achieve a high photon flux density by focusing the beam onto a sample with a high numerical aperture (NA) microscope... 

Light-matter interactions can be described via an induced polarization, i.e., the induced dipole moment per unit volume. Ultrafast laser pulses, which are used in laser scanning microscopes, have high enough intensity to induce a nonlinear polarization in various materials. For intense optical electric field E, the polarization vector P can be expanded in the power series (Boyd 1992)... 

A formal expression for the resonant nonlinear susceptibility can be obtained by describing the light-matter interactions in a density matrix formalism (Boyd 2003 Mukamel 1995), which is beyond the scope of this chapter. A third-order perturbative expansion of the system s density matrix yields the following form for the nonlinear susceptibility ... 

The microscopic theory of light-matter interaction relates o oj) to a matrix element of the electric dipole operator d of the molecule,... 

Orientation of molecules can normally be detected using polarized light in either transmission or scattering experiments. The prediction of the observed effect (birefringence or dichroism, for example) requires a description of the basic light-matter interaction combined with a calculation of the distribution of orientations associated with the individual molecules or segments of molecules. 

To understand why control over the total cross section is lost and how the backward-forward symmetry is broken, we analyze in some detail the simplest case in this class, namely the interference between a one-photon and a two-photon absorption process [78], Consider irradiating a molecule by a field composed of two modes, o>2 and a)h with a)2 = 2coh for which the light-matter interaction is... 

We have written this monograph with the mature chemistry or physics graduate student in mind the development is systematic, starting with the fundamental principles of light-matter interactions and concluding with a wide variety of specific topics. We endeavor to include a sufficient number of steps throughout the book to allow self-study or use in class. To retain the focus on the role of quantum inter-1 ference in control, we tend to utilize examples from our own research, while i including samples from that of others. This focus is partially made possible by the recent appearance of a comprehensive survey of the field by Rice and Zhao... 

The rapid development of techniques for cooling and trapping atoms using laser light has created a new subfield of atomic physics. Research opportunities include the study of matter at ultra low temperature, ultra precise atomic spectroscopy and the study of light-matter interaction in a new quantum regime. 

The light-matter interactions of the Raman FID experiment are illustrated in Fig. 3a. Light pulses are needed at two frequencies Laser (L) and Stokes (S), with their frequency difference adjusted to the vibrational transition energy. An initial pair of Laser and Stokes pulses (pair I) excites the vibration through a Raman interaction. The density matrix of the vibration is transferred from the pure ground state (pm) to a coherent superposition of the v = 0 and v = 1 states (poi)-... 

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