Tuesday, August 13, 2019

High speed stereo imaging techniques for flame studies Research Proposal

High speed stereo imaging techniques for flame studies - Research Proposal Example Researchers have invented several laser sources currently in use for several purposes. According to Blaum (2003), these first laser sources are expensive though efficient; hence the need to improve them in terms of reducing the cost while maintaining efficiency. Caspani (2013) says examples of novel laser sources include optical parametric oscillators (OPOs) and diode-pumped Nd lasers. These laser sources have certain properties and behavior as explained in the following paragraphs. Optical parametric oscillators involve optical cavities that resonate at comb frequencies. They have ultra-small volume due to their optical cavities with dimensions in microns. The ultra-small volume results in increased sensitivity to heat induced by a pump laser; hence shifting the cavity resonance. Chang (2010) says this needs continuous manipulation of the pump wavelength in order to track the thermal drift. When pumped by an appropriate external laser, the micro cavities generate multiple, equally spaced new frequencies through nonlinear optical processes. Diode-pumped Nd lasers include Nd: YVO4, Nd: GdVO4, Nd: FAP, Nd: SFAP, and Nd: SVAP and are all crystals in nature. According to Liu (2014), the crystals belong to two different types of structures. Both Nd: YVO4 and Nd: GdVO4 have the zircon (vanadate) structure which is tetragonal with a space group of141/amd while Nd: FAP, Nd: SFAP and Nd: SVAP have the apatite structure which is hexagonal with space group of P63/m. They all have high emission-section lifetime product, which means they should have a low threshold. According to Wirsig (2010), the temperature dependence (dn/dT) is positive for the vanadates while negative for the apatites meaning the vanadates have higher thermal sensing than the apatites. According to Patterson (1989), the thermal conductivity of the vanadates goes up to 2.5 times than the apatites;

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