Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 6 de 6
Filter
Add more filters










Database
Language
Publication year range
1.
Opt Express ; 21(8): 9353-64, 2013 Apr 22.
Article in English | MEDLINE | ID: mdl-23609646

ABSTRACT

Pump-probe microscopy is an imaging technique that delivers molecular contrast of pigmented samples. Here, we introduce pump-probe nonlinear phase dispersion spectroscopy (PP-NLDS), a method that leverages pump-probe microscopy and spectral-domain interferometry to ascertain information from dispersive and resonant nonlinear effects. PP-NLDS extends the information content to four dimensions (phase, amplitude, wavelength, and pump-probe time-delay) that yield unique insight into a wider range of nonlinear interactions compared to conventional methods. This results in the ability to provide highly specific molecular contrast of pigmented and non-pigmented samples. A theoretical framework is described, and experimental results and simulations illustrate the potential of this method. Implications for biomedical imaging are discussed.


Subject(s)
Microscopy/instrumentation , Molecular Imaging/instrumentation , Spectrum Analysis/instrumentation , Computer-Aided Design , Equipment Design , Equipment Failure Analysis , Nonlinear Dynamics
2.
Biomed Opt Express ; 3(5): 854-62, 2012 May 01.
Article in English | MEDLINE | ID: mdl-22567580

ABSTRACT

Microscopy with nonlinear phase contrast is achieved by a simple modification to a nonlinear pump-probe microscope. The technique measures cross-phase modulation by detecting a pump-induced spectral shift in the probe pulse. Images with nonlinear phase contrast are acquired both in transparent and absorptive media. In paraffin-embedded biopsy sections, cross-phase modulation complements the chemically-specific pump-probe images with structural context.

3.
Opt Lett ; 37(8): 1310-2, 2012 Apr 15.
Article in English | MEDLINE | ID: mdl-22513669

ABSTRACT

A recently developed nonlinear optical pump-probe microscopy technique uses modulation transfer to sensitively extract excited-state dynamics of endogenous biological pigments, such as eumelanin and pheomelanin. In this work, we use this method to image and characterize several inorganic and organic pigments used in historical art. We show substantial differences in the near-IR pump-probe signatures from nominally similar pigments and suggest extensions to art restoration.


Subject(s)
Coloring Agents/analysis , Microscopy/methods , Paintings , Absorption , Color , Coloring Agents/chemistry , Optical Phenomena , Time Factors
4.
Opt Lett ; 37(5): 800-2, 2012 Mar 01.
Article in English | MEDLINE | ID: mdl-22378398

ABSTRACT

We demonstrate a cross-phase modulation measurement technique based on the sensitive detection of modulation transfer in a pump-probe setup. By modulating the amplitude of the pump beam and spectrally analyzing the probe beam, we achieve a rapid, background-free measurement of nonlinear phase modulation using power levels acceptable in biological imaging. This measurement technique would allow the extension of widely employed phase microscopy methods to the nonlinear regime, providing intrinsic and universal nonlinear contrast for biological imaging.


Subject(s)
Molecular Imaging/methods , Optical Phenomena , Breast Neoplasms/pathology , Color , Microscopy , Nonlinear Dynamics , Spectrum Analysis
5.
Opt Express ; 18(12): 12727-35, 2010 Jun 07.
Article in English | MEDLINE | ID: mdl-20588401

ABSTRACT

We have recently developed a spectral re-shaping technique to simultaneously measure nonlinear refractive index and nonlinear absorption. In this technique, the information about the nonlinearities is encoded in the frequency domain, rather than in the spatial domain as in the conventional Z-scan method. Here we show that frequency encoding is much more robust with respect to scattering. We compare spectral re-shaping and Z-scan measurements in a highly scattering environment and show that reliable spectral re-shaping measurements can be performed even in a regime that precludes standard Z-scans.

6.
Opt Lett ; 33(13): 1482-4, 2008 Jul 01.
Article in English | MEDLINE | ID: mdl-18594672

ABSTRACT

We have designed a common-mode interferometric acousto-optic pulse shaper that is capable of shaping individual pulses differently from a mode-locked laser. The design enables the measurement of weak nonlinear optical signals such as two-photon absorption and self-phase modulation at megahertz rates. The experimental apparatus incorporates homodyne detection as a means of resolving the phase of the detected signals. The fast data acquisition rate and the ability to perform measurements in scattering media make this experimental apparatus amenable to imaging applications analogous to measurements of two-photon fluorescence using a mode-locked laser.


Subject(s)
Acoustics/instrumentation , Interferometry/instrumentation , Optics and Photonics/instrumentation , Photometry/instrumentation , Signal Processing, Computer-Assisted/instrumentation , Equipment Design , Equipment Failure Analysis , Photometry/methods
SELECTION OF CITATIONS
SEARCH DETAIL
...