Title:	Nonlinear optical studies in tetraphenyl-porphyrin-doped boric acid glass using picosecond pulses
Authors:	Rao, Divakara K. Anantha Ramakrishna, S. Gupta, P.K.
Issue Date:	Jan-2001
Publisher:	Springer
Citation:	Applied Physisc B: Laser and Optics, 2001, Vol.72, p215-219
Abstract:	We report the results of our studies on the nonlinear optical response of thin films of tetraphenyl porphyrin doped in boric acid glass for picosecond-duration pulses. The fluence-dependent transmission measurements show that the sample exhibits reverse saturation behavior at 532 nm and saturable absorber action at 683 nm. By fitting the nonlinear transmission data at these wavelengths to a rate equation model, values for CSe and CL the excited singlet and ground state cross sections were obtained. The large value (,8) for CSe/CL makes it a potential material for optical limiting at 532 nm, whereas at 683 nm the ratio CL/CSe,4.3. Intensity dependence of degenerate forward four-wave mixing at 683 nm was also investigated to establish the order and magnitude of the nonlinearity. The forward four-wave mixing signal at 683 nm showed a cubic dependence on the input intensity, establishing the third-order nonlinearity. A value of 4210-12 esu for the third-order susceptibility |L(3)| was estimated from the measured efficiency. The time response of the nonlinearity was measured by the pump-probe transmission experiment, resulting in a decay constant of about 1.8 ns for the repopulation of the ground singlet state at 683 nm.
Description:	Restricted Access.
URI:	http://hdl.handle.net/2289/2733
ISSN:	0946-2171 1432-0649 (Online)
Alternative Location:	http://dx.doi.org/10.1007/s003400000393
Copyright:	2001 Springer
Appears in Collections:	Research Papers (TP)

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