Remarkable optical limiting and stabilization effects of a malononitrile derivative on 1064 nm pulsed laser

A malononitrile derivative, 2-[2,5-bis-(4-diethylamino-benzylidene)-cyclopentylidene]-malononitrile (S2), is reported to exhibit a much more remarkable optical limiting and stabilization behaviors on 1064 nm pulsed laser compared with a typical stilbazolium dye, 4-[2-(4-diethylamino-phenyl)vinyl]-1-ethyl-pyridinium (R1). The optical limiting mechamisms of S2 and R1 under ns pulsed laser are both due to a two-photon absorption induced excited state absorption process. A superior large excited state absorption cross section of 2.6 x 10(-5) cm(2) at 1064 nm is found as the main reason to the remarkable optical limiting effect of S2. Meanwhile, S2 presents higher thermal stability and equivalent photochemical stability compared with R1. (C) 2013 AIP Publishing LLC.