Title:	Optical limiting behavior of the natural dye extract from Indigofera Tinctoria leaves
Authors:	Das, Beryl Chandramohan Niranjan, Reji Philip, Reji
Keywords:	Indigofera Tinctoria Natural dye Optical limiter Z-scan Nonlinear absorption coefficient
Issue Date:	Apr-2021
Publisher:	Elsevier
Citation:	Optical Materials, 2021, Vol. 114, pp110925
Abstract:	In this work, we extract the natural dye ingredient found in Indigofera Tinctoria leaves, and investigate its nonlinear optical absorption by employing the Z-scan technique. The dye is extracted from Indigo powder which is commercially available for hair coloring applications. The powder, which is made by grinding Indigofera Tinctoria leaves into fine particles, is mixed with water, sonicated, centrifuged and filtered to give an optically clear extract. Linear absorption of the extract is measured in the visible spectral region using a spectrophotometer. Nonlinear absorption in the green spectral region is measured using 5 ns (5 × 10−9 s), 532 nm laser pulses obtained from a frequency-doubled Nd:YAG laser. The Indigofera Tinctoria dye is found to show excellent nonlinear absorption, which arises from strong reverse saturable absorption occurring in the sample at this wavelength. The third order nonlinear absorption coefficient, which is obtained by numerically fitting the Z-scan data to the nonlinear transmission equation, has a high value in the order of 10−10 m/W. This high nonlinear absorption, which is in the same range as that of materials such as graphene oxide, leads to an excellent optical limiting behavior, making Indigofera Tinctoria a potential candidate for fabricating optical limiter devices for eye and sensor protection.
Description:	Restricted Access.
URI:	http://hdl.handle.net/2289/7760
ISSN:	0925-3467
Alternative Location:	https://doi.org/10.1016/j.optmat.2021.110925
Copyright:	2021, Elsevier B.V.
Appears in Collections:	Research Papers (LAMP)

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