Energy penetrated and inverse bremsstrahlung absorption co-efficient in laser ablated germanium plasma

摘要

In the present experimental conditions, at Nd:YAG laser in fundamental (1064) nm, at laser irradiance 1.0 x 10(11) Wcm(-2) the (IB) absorption alpha(ib) is approximately equal to (0.0204 cm-1). In present work irradiance is varied from 1.0 x 10(11) to 1.8 x 10(11) Wcm(-2) and inverse bremsstrahlung varies from 2.0 x 10(-3) to 1.2 x 10(-2) cm(-1). The power absorbed by germanium target surface is found to be P-abs = 2.07 x 10(8) Wcm(-2) and 1.04 x 10(3) Wcm(-2) is reflected back from germanium surface. Whereas at highest laser irradiance 1.8 x 10(11) Wcm(-2) the power absorbed by surface is found to be P-abs = 3.67 x 10(8) Wcm(-2) and 1.84 x 10(3)Wcm(-2) is reflected back from germanium surface. In present work we have calculated laser absorbance and percentage which is estimated by absorbed light throughout the original irradiance I-0 at target surface, in present work absorbance at germanium surface is 0.2 where as reflectivity R of germanium sample which is found to be 0.39 for 1064 nm wavelength. At irradiance I-0 1.0 x 10(11) Wcm(-2) the energy penetrated is E similar to 5.05 x 10(10) Wcm(-2) and for high laser irradiance at I-0 1.8 x 10(11) Wcm(-2) the energy penetrated is E similar to 8.95 x 10(10) Wcm(-2) respectively. (C) 2019 Elsevier B.V. All rights reserved.