Ultrafast transient absorption of eumelanin suspensions: the role of inverse Raman scattering

Abstract

An ultrafast investigation is carried out on synthetic eumelanin suspended either in water or in DMSO-methanol. Upon photoexcitation by visible femtosecond pulses, the transient absorption (TA) dynamics of the suspensions are probed in a broad visible spectral range, showing clear nonlinearities. The latter arise from pump-probe interactions that induce the inverse Raman scattering (IRS) effect. We show how eumelanin TA dynamics are modified in proximity of the solvent Stokes and anti-Stokes scattering peaks, demonstrating that IRS affects the sign of TA but not the relaxation times. We compare the results obtained in both suspensions, unveiling the role of the surrounding environment. Eventually, the intrinsic response of synthetic eumelanin to ultrafast photoexcitation is evaluated.


Autore Pugliese

Tutti gli autori

  • Aloi A. , Brunetti A. , Perna G. , Lasalvia M. , Capozzi V.G. , Tommasi R.

Titolo volume/Rivista

BIOMEDICAL OPTICS EXPRESS


Anno di pubblicazione

2015

ISSN

2156-7085

ISBN

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Nessuna citazione

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