Femtosecond pulse shaping enables detection of optical Kerr-effect (OKE) dynamics for molecular imaging.


Journal Article

We apply femtosecond pulse shaping to generate optical pulse trains that directly access a material's nonlinear refractive index (n2) and can thus determine time-resolved optical Kerr-effect (OKE) dynamics. Two types of static pulse trains are discussed: The first uses two identical fields delayed in time, plus a pump field at a different wavelength. Time-resolved OKE dynamics are retrieved by monitoring the phase of the interference pattern produced by the two identical fields in the Fourier-domain (FD) as a function of pump-probe-time-delay (where the probe is one of the two identical fields). The second pulse train uses three fields with equal time delays, but with the center field phase shifted by π/2. In this pulse scheme, changes on a sample's nonlinear refractive index produce a new frequency in the FD signal, which in turn yields background-free intensity changes in the conjugate (time) domain and provides superior signal-to-noise ratios. The demonstrated sensitivity improvements enable, for the first time to our knowledge, molecular imaging based on OKE dynamics.

Full Text

Duke Authors

Cited Authors

  • Robles, FE; Fischer, MC; Warren, WS

Published Date

  • August 2014

Published In

Volume / Issue

  • 39 / 16

Start / End Page

  • 4788 - 4791

PubMed ID

  • 25121875

Pubmed Central ID

  • 25121875

Electronic International Standard Serial Number (EISSN)

  • 1539-4794

International Standard Serial Number (ISSN)

  • 0146-9592

Digital Object Identifier (DOI)

  • 10.1364/ol.39.004788


  • eng