Optics Letters

Highly flexible and efficient top-emitting organic light-emitting devices with ultrasmooth Ag anode

Y.-F. Liu — Thu, 17 May 2012 00:00:00 EST

Y.-F. Liu, J. Feng, D. Yin, Y.-G. Bi, J.-F. Song, Q.-D. Chen, H.-B. Sun
We demonstrate highly flexible and efficient top-emitting organic light-emitting devices (TOLEDs) by using an ultrasmooth Ag anode. A template-stripping process has been employed to create the ultrasmooth Ag anode on a photopolymer substrate. The flexible TOLEDs obtained by this method keep good ... [Opt. Lett. 37, 1796-1798 (2012)]

Stable bright and vortex solitons in photonic crystal fibers with inhomogeneous defocusing nonlinearity

Valery E. Lobanov — Thu, 17 May 2012 00:00:00 EST

Valery E. Lobanov, Olga V. Borovkova, Yaroslav V. Kartashov, Boris A. Malomed, Lluis Torner
We predict that a photonic crystal fiber whose strands are filled with a defocusing nonlinear medium can support stable bright solitons and also vortex solitons if the strength of the defocusing nonlinearity grows toward the periphery of the fiber. The domains of soliton existence depend on the ... [Opt. Lett. 37, 1799-1801 (2012)]

Polarization-dependent refractometer for discrimination of temperature and ambient refractive index

H.-J. Kim — Thu, 17 May 2012 00:00:00 EST

H.-J. Kim, O.-J. Kwon, S. B. Lee, Y.-G. Han
Transmission characteristics of polarization-dependent refractometer based on a surface long-period grating (SLPG) inscribed in a D-shaped photonic crystal fiber (PCF) are investigated. The birefringence of SLPG produces the separation of transmission spectra for TE and TM polarization modes. We ... [Opt. Lett. 37, 1802-1804 (2012)]

Quantitative pupil analysis in stimulated emission depletion microscopy using phase retrieval

Emil B. Kromann — Thu, 17 May 2012 00:00:00 EST

Emil B. Kromann, Travis J. Gould, Manuel F. Juette, Jens E. Wilhjelm, Joerg Bewersdorf
The resolution attainable with stimulated emission depletion (STED) microscopy greatly depends on the quality of the STED laser focus. So far, visual inspection of a measured STED focus has been the only convenient means of gauging the source of aberrations. Here we describe a method, requiring no ... [Opt. Lett. 37, 1805-1807 (2012)]

Optimized annular phase masks to extend depth of field

Xutao Mo — Thu, 17 May 2012 00:00:00 EST

Xutao Mo
A radially symmetric phase mask composed of several annular zones with equal area (called APM) was designed based on the incoherent imaging theory from Fourier Optics. The phase of any ring equals minus of the phase function caused by certain defocus. Another circularly symmetric phase mask similar ... [Opt. Lett. 37, 1808-1810 (2012)]

Improved measurement of polarization state in terahertz polarization spectroscopy

M. Neshat N. P. Armitage — Thu, 17 May 2012 00:00:00 EST

M. Neshat, N. P. Armitage
A calibration scheme is presented for improved polarization state measurement of terahertz pulses. In this scheme the polarization response of a two-contact terahertz photoconductive detector is accurately measured, and is used to correct for the impact of the nonidealities of the detector. ... [Opt. Lett. 37, 1811-1813 (2012)]

Bipolar resistance effect observed in CdSe quantum-dots dominated structure of Zn/CdSe/Si

Shuai Liu — Thu, 17 May 2012 00:00:00 EST

Shuai Liu, Ping Cheng, Hui Wang
In this study, we report our new finding of bipolar resistance effect (BRE) in quantum dots (QDs)-embedded structure of Zn/CdSe/Si. This effect features a remarkable linear resistance change and an enhanced BRE when a laser moves along the surface of the structure. The results show that the ... [Opt. Lett. 37, 1814-1816 (2012)]

A spectrally constrained dual-band normalization technique for protoporphyrin IX quantification in fluorescence-guided surgery

P. A. Valdés — Thu, 17 May 2012 00:00:00 EST

P. A. Valdés, F. Leblond, A. Kim, B. C. Wilson, K. D. Paulsen, D. W. Roberts
We report a dual-band normalization technique for in vivo quantification of the metabolic biomarker, protoporphyrin IX (PpIX), during brain tumor resection procedures. The accuracy of the approach was optimized in tissue simulating phantoms with varying absorption and scattering properties, ... [Opt. Lett. 37, 1817-1819 (2012)]

Plasmonic quarter-wave plate

A. Roberts L. Lin — Thu, 17 May 2012 00:00:00 EST

A. Roberts, L. Lin
Here we present a strategy for designing wave plates utilizing resonances of subwavelength apertures in metallic films. Specifically, we show that it is possible to tune the geometry in a periodic array of cross-shaped apertures in a silver film to produce a quarter-wave plate at a particular ... [Opt. Lett. 37, 1820-1822 (2012)]

Flexible optitrode for localized light delivery and electrical recording

S.-T. Lin — Wed, 16 May 2012 00:00:00 EST

S.-T. Lin, J. C. Wolfe, J. A. Dani, W.-C. Shih
We present optitrode, a miniaturized flexible probe for integrated, localized light delivery and electrical recording. This device features an annular light guide with transparent polymer and fused silica layers surrounding a twisted-wire tetrode. We have developed a novel fabrication process, ... [Opt. Lett. 37, 1781-1783 (2012)]

Fourier transform-based iterative method for differential phase-contrast computed tomography

Wenxiang Cong — Wed, 16 May 2012 00:00:00 EST

Wenxiang Cong, Atsushi Momose, Ge Wang
In this Letter, a novel Fourier transform-based iterative method is proposed to reconstruct a refractive index distribution in an object directly from measured differential phase shifts. This reconstruction method offers distinct advantages over the analytic method in cases of noisy and/or few-view ... [Opt. Lett. 37, 1784-1786 (2012)]

Generation of tunable octave-spanning mid-infrared pulses by filamentation in gas media

Mark Cheng — Wed, 16 May 2012 00:00:00 EST

Mark Cheng, Anthony Reynolds, Heather Widgren, Munira Khalil
The continued development of femtosecond mid-infrared (IR) sources with ultrabroad spectral width is critical for probing and controlling complex molecular structural dynamics on an ultrafast timescale. We report on a sub-20 fs, coherent mid-IR source with an octave-spanning spectral bandwidth ... [Opt. Lett. 37, 1787-1789 (2012)]

Young’s two-slit interference of vector light fields

Yongnan Li — Wed, 16 May 2012 00:00:00 EST

Yongnan Li, Xi-Lin Wang, Hu Zhao, Ling-Jun Kong, Kai Lou, Bing Gu, Chenghou Tu, Hui-Tian Wang
We explore the peculiar interference behaviors of the vector fields in the Young’s two-slit configuration. The interference patterns have a chessboard structure in the middle region and depend on the topological charge and the initial phase of the input vector field. The results have ... [Opt. Lett. 37, 1790-1792 (2012)]

Pulse propagation of photon-added coherent states in waveguides with side-coupled nonlinear cavities

Paolo Longo Kurt Busch — Wed, 16 May 2012 00:00:00 EST

Paolo Longo, Kurt Busch
We present a theoretical analysis of pulse propagation in a waveguide with a side-coupled Kerr nonlinear cavity. As a specific application, we demonstrate how the nonlinearity has a profound influence on transport properties of a photon-added coherent state. We find that the fields provided by the ... [Opt. Lett. 37, 1793-1795 (2012)]