APL Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

17 Nov 2008

Volume 93, Issue 20, Articles (20xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 93, 201101 (2008); http://dx.doi.org/10.1063/1.3025818 (3 pages)

W. Dai and C. M. Soukoulis
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Converging and wave guiding of Gaussian beam by two-layer dielectric rods

W. Dai and C. M. Soukoulis

Appl. Phys. Lett. 93, 201101 (2008); http://dx.doi.org/10.1063/1.3025818 (3 pages) | Cited 2 times

Online Publication Date: 17 November 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have shown that a two-layer dielectric structure can give excellent beaming and enhanced transmission simultaneously of a Gaussian source. The front surface of the layer of dielectric rods supports surface states and the rear grading layer couples the surface states to radiation modes. By repeating periodically this two-layer structure, one can obtain excellent beaming and enhanced transmission for very long distances.
Show PACS
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation
42.79.Gn Optical waveguides and couplers

Compensation of thermal refraction effect in high-Q toroidal microresonator by polydimethylsiloxane coating

L. He, Y.-F. Xiao, C. Dong, J. Zhu, V. Gaddam, and L. Yang

Appl. Phys. Lett. 93, 201102 (2008); http://dx.doi.org/10.1063/1.3030986 (3 pages) | Cited 26 times

Online Publication Date: 17 November 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We experimentally and theoretically characterize the thermal refraction effect in a silica microtoroid and demonstrate that such effect can be reduced or even eliminated by applying a thin layer of polydimethylsiloxane (PDMS) to the surface of the silica resonator. By increasing the coating thickness, the whispering gallery modes (WGMs) experience a transition from redshift to blueshift induced by thermal absorption. Experiment results demonstrate that at the thickness of 0.52 μm, the fundamental WGM with observed Q factor of 1.5×106 shows no shift with the input optical power since the thermal refraction of the silica for this mode is compensated completely by the PDMS layer, which has an opposite thermal refraction effect. This work shows that the PDMS layer could be used to reduce thermal noise in high-Q silica microcavities for applications in sensing, lasing, and nonlinear optics.
Show PACS
42.79.-e Optical elements, devices, and systems
85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices

Coherent anti-Stokes Raman microspectroscopy using spectral focusing with glass dispersion

Israel Rocha-Mendoza, Wolfgang Langbein, and Paola Borri

Appl. Phys. Lett. 93, 201103 (2008); http://dx.doi.org/10.1063/1.3028346 (3 pages) | Cited 21 times

Online Publication Date: 18 November 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate experimentally that coherent anti-Stokes Raman microspectroscopy with high spectral resolution is achieved using femtosecond laser pulses chirped up to a few picoseconds by glass elements of known group-velocity dispersion without significant intensity losses. By simply choosing the length of the glass, the chirp of Stokes and pump pulses is tailored to obtain a spectral resolution given by the Fourier limit of the chirped pulse duration. We show that for chirped pulse durations shorter than or comparable to the Raman coherence time, maximum signal occurs for a pump arriving after the Stokes pulse, a time-ordering effect confirmed by numerical simulations.
Show PACS
78.35.+c Brillouin and Rayleigh scattering; other light scattering
78.47.J- Ultrafast spectroscopy (<1 psec)
81.05.Kf Glasses (including metallic glasses)
61.43.Fs Glasses

Strain-induced low dimensional confinement structures

Nadir Sekkal and V. R. Velasco

Appl. Phys. Lett. 93, 201104 (2008); http://dx.doi.org/10.1063/1.3030981 (3 pages)

Online Publication Date: 18 November 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We propose here confinement structures similar to heterostructures and superlattices. The present structures can be obtained by applying strain to a single material in a periodic or aperiodic way. The conversion of an indirect gap into an optical active direct or quasidirect gap problem has also been investigated together with the role of zone folding in this phenomenon.
Show PACS
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
73.63.-b Electronic transport in nanoscale materials and structures
73.43.Jn Tunneling
71.70.Fk Strain-induced splitting
Author Select

Multiple pulse thermal damage thresholds of materials for x-ray free electron laser optics investigated with an ultraviolet laser

Stefan P. Hau-Riege, Richard A. London, Richard M. Bionta, Regina Soufli, Dmitri Ryutov, Michael Shirk, Sherry L. Baker, Patrick M. Smith, and Pradeep Nataraj

Appl. Phys. Lett. 93, 201105 (2008); http://dx.doi.org/10.1063/1.3021081 (3 pages) | Cited 2 times

Online Publication Date: 19 November 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Optical elements to be used for x-ray free electron lasers (XFELs) must withstand multiple high-fluence pulses. We have used an ultraviolet laser to study the damage of two candidate materials, crystalline Si and B4C-coated Si, emulating the temperature profile expected to occur in optics exposed to XFEL pulses. We found that the damage threshold for 105 pulses is ∼ 20% to 70% lower than the melting threshold.
Show PACS
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
41.60.Cr Free-electron lasers
42.79.-e Optical elements, devices, and systems
61.82.Fk Semiconductors

Experimental demonstration of tunable negative phase velocity and negative refraction in a ferromagnetic/ferroelectric composite metamaterial

Hongjie Zhao, Lei Kang, Ji Zhou, Qian Zhao, Longtu Li, Liang Peng, and Yang Bai

Appl. Phys. Lett. 93, 201106 (2008); http://dx.doi.org/10.1063/1.3033397 (3 pages) | Cited 7 times

Online Publication Date: 20 November 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A tunable left-handed transmission is demonstrated experimentally in a ferromagnetic/ferroelectric composite metamaterial (CMM) consisting of an array of yttrium iron garnet (YIG) rods combined with barium strontium titanate (BST) rods. We observed a passband in the CMM within the overlap of the stop bands of YIG rods alone and BST rods alone. Both measured phase velocity and refractive index of the CMM are shown to be negative at the relevant frequency range. The frequency showing left handedness can be adjusted continuously, dynamically, and reversibly by an applied magnetic field with a sensitive response of 3.5 GHz/kOe.
Show PACS
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
75.80.+q Magnetomechanical effects, magnetostriction
77.22.Ch Permittivity (dielectric function)
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
75.50.Dd Nonmetallic ferromagnetic materials
77.80.-e Ferroelectricity and antiferroelectricity

Phonon-assisted ultraviolet anti-Stokes photoluminescence from GaN film grown on Si (111) substrate

Suvranta K. Tripathy, Guibao Xu, Xiaodong Mu, Yujie J. Ding, Muhammad Jamil, Ronald A. Arif, Nelson Tansu, and Jacob B. Khurgin

Appl. Phys. Lett. 93, 201107 (2008); http://dx.doi.org/10.1063/1.3030883 (3 pages) | Cited 2 times

Online Publication Date: 20 November 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Phonon-assisted anti-Stokes photoluminescence (ASPL) in the ultraviolet region has been observed in the GaN film grown on a Si (111) substrate. The ASPL peaks are observable only at sufficiently low temperatures. In addition, even if the photon energy is ≈ 318 meV below the transition energy for bound excitons, the ASPL peaks can be still observed. Based on our analysis, the donor-acceptor pairs and bound excitons have played primary roles in the generation of ASPL. Upon the absorption of photons, the ionizations of the neutral donors and neutral acceptors are assisted by longitudinal-optical phonons.
Show PACS
78.55.Cr III-V semiconductors
78.66.Fd III-V semiconductors
71.35.-y Excitons and related phenomena

Ponderomotive electron acceleration by polarization-gated surface-enhanced optical fields

Peifen Lu, Jian Wu, Hongxing Qi, and Heping Zeng

Appl. Phys. Lett. 93, 201108 (2008); http://dx.doi.org/10.1063/1.3020711 (3 pages) | Cited 2 times

Online Publication Date: 21 November 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We study ponderomotive electron acceleration with polarization-gated surface-plasmon-resonance enhanced optical fields excited by two counter-incident femtosecond laser pulses. Such a polarization-gated excitation scheme creates an intense linearly polarized high-gradient evanescent field for electron acceleration. The maximum kinetic energy of the accelerated ultrafast electrons is doubled with a symmetric angular distribution about the normal of the metal surface as compared with the conventional one-pulse excitation scheme.
Show PACS
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
78.47.-p Spectroscopy of solid state dynamics
42.25.Ja Polarization
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close