13 results match your criteria Journal of the Optical Society of America B: Optical Physics [Journal]

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Tomographic phase microscopy: principles and applications in bioimaging [Invited].

J Opt Soc Am B 2017;34(5):B64-B77

Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.

Tomographic phase microscopy (TPM) is an emerging optical microscopic technique for bioimaging. TPM uses digital holographic measurements of complex scattered fields to reconstruct three-dimensional refractive index (RI) maps of cells with diffraction-limited resolution by solving inverse scattering problems. In this paper, we review the developments of TPM from the fundamental physics to its applications in bioimaging. Read More

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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5788179PMC
January 2017
4 Reads

Direct comparison of time-resolved Terahertz spectroscopy and Hall Van der Pauw methods for measurement of carrier conductivity and mobility in bulk semiconductors.

J Opt Soc Am B 2017 Jul 12;34(7):1392-1406. Epub 2017 Jun 12.

Radiation Physics Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA.

Charge carrier conductivity and mobility for various semiconductor wafers and crystals were measured by ultrafast above bandgap, optically excited Time-Resolved Terahertz Spectroscopy (TRTS) and Hall Van der Pauw contact methods to directly compare these approaches and validate the use of the non-contact optical approach for future materials and device analyses. Undoped and doped silicon (Si) wafers with resistances varying over six orders of magnitude were selected as model systems since contact Hall measurements are reliably made on this material. Conductivity and mobility obtained at room temperature by terahertz transmission and TRTS methods yields the sum of electron and hole mobility which agree very well with either directly measured or literature values for corresponding atomic and photo-doping densities. Read More

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http://dx.doi.org/10.1364/JOSAB.34.001392DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5600209PMC
July 2017
20 Reads

Gas-phase broadband spectroscopy using active sources: progress, status, and applications.

J Opt Soc Am B 2017 Jan 14;34(1):104-129. Epub 2016 Dec 14.

National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA.

Broadband spectroscopy is an invaluable tool for measuring multiple gas-phase species simultaneously. In this work we review basic techniques, implementations, and current applications for broadband spectroscopy. We discuss components of broad-band spectroscopy including light sources, absorption cells, and detection methods and then discuss specific combinations of these components in commonly-used techniques. Read More

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http://dx.doi.org/10.1364/JOSAB.34.000104DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5473295PMC
January 2017
8 Reads

Limits of Femtosecond Fiber Amplification by Parabolic Pre-Shaping.

J Opt Soc Am B 2017 Mar;34(3):A37-A42

School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA.

We explore parabolic pre-shaping as a means of generating and amplifying ultrashort pulses. We develop a theoretical framework for modeling the technique and use its conclusions to design a femtosecond fiber amplifier. Starting from 9 ps pulses, we obtain 4. Read More

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https://www.osapublishing.org/abstract.cfm?URI=josab-34-3-A3
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http://dx.doi.org/10.1364/JOSAB.34.000A37DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5358092PMC
March 2017
10 Reads

Pulsed operation of a miniature scalar optically pumped magnetometer.

J Opt Soc Am B 2017 ;34(7):1429-1434

University of Colorado, Boulder, Colorado 80309, USA.

A scalar magnetic field sensor based on a millimeter-size Rb vapor cell is described. The magnetometer uses nearly copropagating pump and probe laser beams, amplitude modulation of the pump beam, and detection through monitoring the polarization rotation of the detuned probe beam. The circularly polarized pump laser resonantly drives a spin precession in the alkali atoms at the Larmor frequency. Read More

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http://dx.doi.org/10.1364/JOSAB.34.001429DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5966019PMC
January 2017
3 Reads

Exciton Dynamics in Monolayer Transition Metal Dichalcogenides.

J Opt Soc Am B 2016 Jul 19;33(7):C39-C49. Epub 2016 Apr 19.

Department of Physics, University of Washington, Seattle, Washington 98195.

Since the discovery of semiconducting monolayer transition metal dichalcogenides, a variety of experimental and theoretical studies have been carried out seeking to understand the intrinsic exciton population recombination and valley relaxation dynamics. Reports of the exciton decay time range from hundreds of femtoseconds to ten nanoseconds, while the valley depolarization time can exceed one nanosecond. At present, however, a consensus on the microscopic mechanisms governing exciton radiative and non-radiative recombination is lacking. Read More

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http://dx.doi.org/10.1364/JOSAB.33.000C39DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5590662PMC
July 2016
8 Reads

Third-order effects in resonant sum-frequency-generation signals at electrified metal/liquid interfaces.

J Opt Soc Am B 2013 Jan;30(1)

National ESCA and Surface Analysis Center for Biomedical Problems, Department of Bioengineering, University of Washington, Box 35170, Seattle, Washington 98195-1750, USA.

Vibrational sum-frequency-generation (SFG) spectroscopy experiments at electrified interfaces involve incident laser radiation at frequencies in the IR and near-IR/visible regions as well as a static electric field on the surface. Here we show that mixing the three fields present on the surface can result in third-order effects in resonant SFG signals. This was achieved for closed packed self-assembled monolayers (SAMs) with molecular groups of high optical nonlinearity and surface potentials similar to those typically applied in cyclic voltammograms. Read More

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http://dx.doi.org/10.1364/JOSAB.30.000219DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3825253PMC
January 2013
6 Reads

Single fiber laser based wavelength tunable excitation for CRS spectroscopy.

J Opt Soc Am B 2013 Jun;30(6):1671-1682

Dept. Elect Eng. & Computer Sci., University of Kansas, Lawrence, KS, 66045, USA.

We demonstrate coherent Raman spectroscopy (CRS) using a tunable excitation source based on a single femtosecond fiber laser. The frequency difference between the pump and the Stokes pulses was generated by soliton self-frequency shifting (SSFS) in a nonlinear optical fiber. Spectra of C-H stretches of cyclohexane were measured simultaneously by stimulated Raman gain (SRG) and coherent anti-Stokes Raman scattering (CARS) and compared. Read More

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https://www.osapublishing.org/abstract.cfm?URI=josab-30-6-16
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http://dx.doi.org/10.1364/JOSAB.30.001671DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3741065PMC
June 2013
11 Reads

Area theorem and energy quantization for dissipative optical solitons.

J Opt Soc Am B 2010 Oct;27(10):1978-1982

Department of Applied Physics, Cornell University, Ithaca, New York 14853, USA.

Soliton area theorems express the pulse energy as a function of the pulse shape and the system parameters. From an analytical solution to the cubic-quintic Ginzbug-Landau equation, we derive an area theorem for dissipative optical solitons. In contrast to area theorems for conservative optical solitons, the energy does not scale inversely with the pulse duration, and in addition there is an upper limit to the energy. Read More

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http://ieeexplore.ieee.org/iel5/5197900/5224262/05225126.pdf
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https://www.osapublishing.org/josab/abstract.cfm?uri=josab-2
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http://dx.doi.org/10.1364/JOSAB.27.001978DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3135379PMC
October 2010
25 Reads

Localized waveguide formation in germanosilicate fiber transmitting femtosecond IR pulses.

J Opt Soc Am B 2008 Feb;25(2):274-278

Biophotonics Imaging Laboratory, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.

Transmission of intense femtosecond 825 nm pulses progressively produces a waveguide at the entrance of a heavily Ge-doped silicate fiber. The waveguide behaves as a multimillimeter long-fiber bandpass filter that scatters away light with wavelengths shorter or longer than 850 nm. This phenomenon has been correlated with the ~800 nm photosensitivity producing type I-IR fiber Bragg gratings in side-written lightly Ge-doped silicate fibers and low-loss waveguides in pure silica bulk glass. Read More

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http://dx.doi.org/10.1364/JOSAB.25.000274DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2884162PMC
February 2008
3 Reads

Effective-substrate theory for optical reflection from a layered substrate.

J Opt Soc Am B 2008 Jan;25(12):2021-2028

Department of Physics, University of California at Davis, Davis, CA 95616, USA.

We show that reflection of a monochromatic light from a semi-infinite medium covered with a stack of layered media is equivalent to that from an effective "semi-infinite medium" characterized by two distinctive optical dielectric constants for the s-polarized and p-polarized components, respectively. Such an effective-substrate approach simplifies the analysis of ellipsometry measurements of a wide range of surface-bound processes including thin film growth and surface-bound reactions. Read More

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https://www.osapublishing.org/abstract.cfm?URI=josab-25-12-2
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http://dx.doi.org/10.1364/JOSAB.25.002021DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2739384PMC
January 2008
5 Reads

Computational study of fluorescence scattering by silver nanoparticles.

J Opt Soc Am B 2007 Sep;24(9):2259-2267

Center for Fluorescence Spectroscopy, Medical Biotechnology Center, University of Maryland School of Medicine, 725 West Lombard Street, Baltimore, Maryland 21201, USA.

We study the nature of fluorescence scattering by a radiating fluorophore placed near a metal nanoparticle with the finite-difference time-domain method. Angle-resolved light-scattering distributions are contrasted with those that result when ordinary plane waves are scattered by the nanoparticle. For certain sized nanoparticles and fluorophore dipoles oriented parallel to the metal surface, we find that the highest scattered fluorescence emission is directed back toward the fluorophore, which is very different from plane-wave scattering. Read More

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http://dx.doi.org/10.1364/JOSAB.24.002259DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2748397PMC
September 2007
6 Reads

Asymptotic screened hydrogenic radial integrals.

J Opt Soc Am B 1988 Dec;5(12):2437-8

Department of Physics, Old Dominion University, Norfolk, Virgina 23529, USA.

The screened hydrogenic radial dipole integral for discrete-discrete transitions from initial state n'l' to final state nl is asymptotically expanded to the lowest order such that the final quantum number n --> infinity. The analytical expression obtained is in terms of confluent hypergeometric functions, and explicit expressions for a few of the specific transitions are derived from them as examples. Read More

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December 1988
6 Reads
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