Beam induced light emission

LASER is an acronym that stands for Light Amplification by Stimulated Emission of Radiation. The laser produces an intense, highly directional beam of light. The most common cause of laser-induced tissue damage is thermal in nature, where the tissue proteins are denatured due to the temperature rise following absorption of laser energy. The human body is vulnerable to the output of certain lasers, and under certain circumstances, exposure can result in damage to the eye and skin. 

Chattopadhyay S, Bohn PW (2004) Direct-write patterning of microstructured porous silicon arrays by focused-ion-beam Pt deposition and metal-assisted electroless etching. J Appl Phys 96 6888 Chattopadhyay S, Bohn PW (2006) Surfactant-induced modulation of light emission in porous silicon produced by metal-assisted electroless etching. Anal Chem 78(17) 6058-6064 Chattopadhyay S, Li X, Bohn PW (2002) In-plane control of morphology and tunable photoluminescence in porous silicon produced by metal-assisted electroless chemical etching. J Appl Phys 91 6134-6140... 

The spatial coherence of the induced emission which renders it possible to focus the laser output into a nearly parallel light beam. 

Light emitted from the source converges on the excitation monochromator, which allows a narrow band of wavelengths to be selected (15 nm) to induce fluorescence of the sample solution in the measurement cell. The emitted light, observed perpendicular to the direction of the incident beam, passes through the emission monochromator, allowing the selection of a narrow band of wavelengths for measurement (Fig. 12.9). The simplest instruments have a double compartment for measurement. This allows the sample solution and a standard fluorescent reference solution to be put into the optical path. 

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