Femtosecond carrier dynamics and saturable absorption in graphene suspensions

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Authors
Kumar, Sunil
Anija, M.
Kamaraju, N.
Vasu, K. S.
Subrahmanyam, K. S.
Sood, A. K.
Rao, C. N. R.
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Abstract
Description
Nonlinear optical properties and carrier relaxation dynamics in graphene, suspended in three different solvents, are investigated using femtosecond (80 fs pulses) Z-scan and degenerate pumpprobe spectroscopy at 790 nm. The results demonstrate saturable absorption property of graphene with a nonlinear absorption coefficient, $beta$, of ~2 to 9x10^-8 cm/W. Two distinct time scales associated with the relaxation of photoexcited carriers, a fast one in the range of 130-330 fs (related to carrier-carrier scattering) followed by a slower one in 3.5-4.9 ps range (associated with carrier-phonon scattering) are observed.
Comment: 3 pages, 2 figures, 2 tables
Keywords
Condensed Matter - Materials Science
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