Amplification of light

Stimulated emission is quantified by the (wavelength dependent) excited state cross-section other processes are important, stimulated emission leads directly to amplification of light. In a material with a volume density fVcxc of excited 5 -states this amplification can be described by... 

In the past few years, erbium doped materials gained much attention in the field of optical communications, since the Er ion shows a broad optical emission at 1540 nm [111], within the main wavelengths window in the telecommunication technology. For this reason Er can be suitable as an active element for the generation and amplification of light in optical devices [112,113], also if limitations for the realization of an efficient planar amplifier are related to the small cross section for Er excitation (typically 10 -10 cm according to the matrix). In order to enhance Er ion pumping efficiency, a possible... 

Electronic Amplification of Light Images Techniques of Image Enhancement... 

The term is a complex tensor whose real part relates to light scattering and whose imaginary-part describes absorption or amplification of light. In the wealc-field (linear) domain it is independent of the field E(r, t). As the field gets stronger, % may become dependent on the field, in which case we say that / has nonlinear contributions. Below, for convenience, we suppress the spatial dependence of %. 

Stracke, A., Wendorff, J. H., Goldmann, D., and Janietz, D. Optical storage in a smectic mesophase thermal amplification of light-induced chromophore orientations and surface relief gratings. Liquid Crystals 2000, 27, pp. 1049-1057. 

In this chapter we summarize basic concepts of lasers with regard to their applications in spectroscopy. A well-founded knowledge of some subjects in laser physics, such as passive and active optical cavities and their mode spectra, amplification of light and saturation phenomena, mode competition and the frequency spectrum of laser emission, will help the reader to gain a deeper understanding of many problems in laser spectroscopy and to achieve optimum performance of an experimental setup. A more detailed treatment of laser physics and an extensive discussion of various types of lasers can be found in textbooks on lasers (see, for instance, [1.1-3, 5.1-4]). For more advanced presentations based on a quantum mechanical description of lasers, the reader is referred to [1.4,5, 5.5-7]. 

Readout noise is the noise that comes from the amplification of the small amount of electrical charge that is produced by the light. 

Semiconductor laser diodes are widely used in CD players, DVDs, printers, telecommunication or laser pointers. In the structure, they are similar to LEDs but they have a resonant cavity where laser amplification takes place. A Fabry-Perot cavity is established by polishing the end facets of the junction diode (so that they act as mirrors) and also by roughening the side edges to prevent leakage of light from the sides of the device. This structure is known as a homojunction laser and is a very basic one. Contemporary laser diodes are manufactured as double heterojunction structures. 

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