Anantharaman, M R; Suchand Sandeep, C S; Jinto, Thomas; Reji, Philip; Swapna, Nair S(AIP Publishing, May 1, 2008)
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Abstract:
We report an optical limiter based on ferrofluids which has a very high shelf life and remarkable
thermal stability, which are important requirements for sustainable use with intense lasers. The
colloidal suspensions contain nanosized particles of approximately 80 Å diameter, with a number
density of the order of 1022 /m3. The nonlinear optical transmission of the samples is studied using
nanosecond and femtosecond laser pulses. Excited state absorption phenomena contribute to
enhanced limiting in the nanosecond excitation regime. An advantageous feature of ferrofluids in
terms of device applications is that their optical properties are controllable by an external magnetic
field.