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All-optical Limiting Behavior of Natural Dyes Extracted from Tea Leaves
M. A. Rahma and H. L. Saadon
Optical nonlinearity in natural dyes extracted from tea leaves, such as black tea (Bt) and green tea (Gt), in different solvents (dimethyl sulfoxide, methanol, ethylene glycol, and deionized water) was measured with a Z-scan technique using a single CW laser at 532 nm, and a novel alloptical limiter based on nonlinear optical responses in natural dyes was presented. Then, the absorption peaks in the 665 and 675 nm regions were detected by UV-vis spectroscopy, and the nonlinear optical parameter n2 for Bt and Gt were determined in different solvents. Finally, power-absorbing and power-spreading configurations were used in investigating all-limiting behavior for Bt and Gt. Results indicated good all-optical limiting behavior, suggesting that tea leaves are potential materials for fabricating all-optical limiter devices used in sensor protection.
Keywords: Natural dye, all-optical limiting, nonlinear optical effect