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

11 Sep 2006

Volume 89, Issue 11, Articles (11xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 89, 111104 (2006); http://dx.doi.org/10.1063/1.2353804 (3 pages)

Yi Yang and Guo Ping Wang
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Optical-fiber interferometer for velocity measurements with picosecond resolution

Jidong Weng, Hua Tan, Xiang Wang, Yun Ma, Shaolou Hu, and Xiaosong Wang

Appl. Phys. Lett. 89, 111101 (2006); http://dx.doi.org/10.1063/1.2335948 (3 pages) | Cited 11 times

Online Publication Date: 11 September 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The conventional Doppler laser-interference velocimeters are made up of traditional optical elements such as lenses and mirrors and will generally restrict its applications in multipoint velocity measurements. By transfering the light from multimode optical fiber to single-mode optical fiber and using the currently available conventional telecommunications elements, the authors have constructed a velocimeter called all-fiber displacement interferometer system for any reflector. The unique interferometer system is only made up of fibers or fiber-coupled components. The viability of this technique is demonstrated by measuring the velocity of an interface moving at velocity of 2133 m/s with 50 ps time resolution. In addition, the concept of optical-fiber mode conversion would provide a way to develop various optical-fiber sensors.
Show PACS
42.81.Pa Sensors, gyros
07.60.Ly Interferometers
06.30.Gv Velocity, acceleration, and rotation
42.79.Qx Range finders, remote sensing devices; laser Doppler velocimeters, SAR, and LIDAR
42.81.Wg Other fiber-optical devices

Scaling of dark count rate with active area in 1.06 μm photon-counting InGaAsP/InP avalanche photodiodes

E. A. Dauler, P. I. Hopman, K. A. McIntosh, J. P. Donnelly, E. K. Duerr, R. J. Magliocco, L. J. Mahoney, K. M. Molvar, A. Napoleone, D. C. Oakley, and F. J. O’Donnell

Appl. Phys. Lett. 89, 111102 (2006); http://dx.doi.org/10.1063/1.2243800 (3 pages) | Cited 8 times

Online Publication Date: 11 September 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Reducing the active area of InGaAsP/InP avalanche photodiodes operated in Geiger mode is investigated for reducing the dark count rate. The dark count rate in Geiger mode is found to scale linearly with the detector’s active area for mesa diameters of 10, 15, and 20 μm. Scaling the mesa size from 20 to 10 μm results in a reduction of the room-temperature dark count rate from 290 to 44 kHz at ∼ 4.5 V of overbias, while the photon detection efficiency is ∼ 45% for all device diameters. The trade-offs associated with shrinking the active area, including reduced optical coupling and higher on-state resistance, are discussed briefly.
Show PACS
85.60.Dw Photodiodes; phototransistors; photoresistors
85.60.Gz Photodetectors (including infrared and CCD detectors)
42.82.Gw Other integrated-optical elements and systems

Optochemical sensor for water monitoring based on SnO2 particle layer deposited onto optical fibers by the electrospray pyrolysis method

A. Cusano, M. Consales, M. Pisco, P. Pilla, A. Cutolo, A. Buosciolo, R. Viter, V. Smyntyna, and M. Giordano

Appl. Phys. Lett. 89, 111103 (2006); http://dx.doi.org/10.1063/1.2335585 (3 pages) | Cited 6 times

Online Publication Date: 11 September 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In this letter, experimental results on the capability of a tin dioxide (SnO2)-based silica optical fiber (SOF) sensor to detect sub-ppm ammonia concentrations in water environments, at room temperature, are presented. SnO2 sensitive layers have been deposited on the fiber end by using the simple and low cost electrostatic spray pyrolysis deposition technique. The surface morphology of the deposited SnO2 layers as well as its influence on the near field profile of the emergent electromagnetic field from the fiber coating have been investigated by means of atomic force microscopy and scanning near field optical microscopy. The room temperature adsorption measurements reveal the excellent sensor resolution of 80 ppb, good recovery features, high repeatability, and fast response times (a few minutes). The results obtained demonstrate the strong potentiality of the proposed SnO2-based SOF sensor to be employed for water quality monitoring applications.
Show PACS
42.81.Pa Sensors, gyros
82.80.-d Chemical analysis and related physical methods of analysis
07.60.Vg Fiber-optic instruments
82.30.Lp Decomposition reactions (pyrolysis, dissociation, and fragmentation)
89.60.Ec Environmental safety

Realization of periodic and quasiperiodic microstructures with sub-diffraction-limit feature sizes by far-field holographic lithography

Yi Yang and Guo Ping Wang

Appl. Phys. Lett. 89, 111104 (2006); http://dx.doi.org/10.1063/1.2353804 (3 pages) | Cited 5 times

Online Publication Date: 11 September 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors experimentally demonstrate a far-field holography for the realization of Ag nanoparticles-embedded periodic and quasiperiodic microstructures with feature sizes beyond the diffraction limit. Periodic cylindrical nanoshell arrays with about 240 nm hole diameter and 12-fold symmetry quasiperiodic structures with 220 nm feature sizes are achieved, respectively, by using a 632.8 nm laser beam. Our results imply that conventional far-field optical technology is capable of fabricating nanostructures in modern micromanufacture.
Show PACS
42.40.My Applications
42.86.+b Optical workshop techniques
81.16.Nd Micro- and nanolithography

Enhanced kinetics of Al0.97Ga0.03As wet oxidation through the use of hydrogenation

M. Le Dû, I. Sagnes, G. Beaudoin, L. Travers, J.-C. Esnault, and J.-C. Harmand

Appl. Phys. Lett. 89, 111105 (2006); http://dx.doi.org/10.1063/1.2348769 (3 pages) | Cited 1 time

Online Publication Date: 11 September 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This letter reports on a different kinetic behavior of the wet thermal oxidation process resulting in AlxOy material depending on the AlAs material growth method, molecular beam epitaxy (MBE) or metal organic vapor phase epitaxy (MOVPE). A higher oxidation rate for MOVPE-grown materia is systemically found. Considering the major role of hydrogen in the wet oxidation reaction, it is believed this observation could be linked with the higher hydrogen residual concentration in MOVPE layers. Using a hydrogen plasma, MBE-grown Al0.97Ga0.03As layers were hydrogened prior to oxidation. This hydrogenated sample showed a ten times enhanced oxidation rate as compared to the nonhydrogenated Al0.97Ga0.03As sample. This behavior is mainly attributed to a hydrogen induced modification of the diffusion limited regime, enhancing the diffusion length of oxidizing species and reaction products in the oxidized layers.
Show PACS
81.65.Mq Oxidation
52.77.-j Plasma applications
68.55.A- Nucleation and growth
66.30.J- Diffusion of impurities
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
81.15.Kk Vapor phase epitaxy; growth from vapor phase

Spatially tunable laser emission in dye-doped cholesteric polymer films

Yuhua Huang, Liang-Pin Chen, Charlie Doyle, Ying Zhou, and Shin-Tson Wu

Appl. Phys. Lett. 89, 111106 (2006); http://dx.doi.org/10.1063/1.2349826 (3 pages) | Cited 13 times

Online Publication Date: 12 September 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A spatially tunable laser emission of the dye-doped cholesteric polymer film is demonstrated by generating a one-dimensional gradient photonic band gap which is cured by an ultraviolet light. A frequency-doubled pulsed Nd:YAG laser is used to pump the film. The lasing wavelength is tunable from 595 to 643 nm by shifting the position of the film with respect to the pumping beam. Since the spatial distribution of the reflection band is fixed in the cholesteric polymer film, the tuning of the laser wavelength does not require any external field. Therefore, the film is portable and has many applications.
Show PACS
42.55.Rz Doped-insulator lasers and other solid state lasers
42.60.Fc Modulation, tuning, and mode locking
42.55.Xi Diode-pumped lasers
42.60.By Design of specific laser systems

Two-photon absorption of matrix-free Ge nanocrystals

Henry Gerung, Yanrui Zhao, Li Wang, Ravinder K. Jain, Timothy J. Boyle, C. Jeffrey Brinker, and Sang M. Han

Appl. Phys. Lett. 89, 111107 (2006); http://dx.doi.org/10.1063/1.2352711 (3 pages) | Cited 6 times

Online Publication Date: 12 September 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors demonstrate that solution synthesized Ge nanocrystals (NCs) display a highly nonlinear optical absorption. The Ge NCs with an average diameter of 5±2 nm are synthesized from germanium(II) bis(trimethylsilyl)amide with hexadecylamine surfactants at 300 °C and 1 atm in argon atmosphere. The resulting Ge NCs in a powder form are then dispersed on a silica glass substrate. Femtosecond pulses at 820 nm wavelength from a mode-locked Ti:sapphire laser are used to measure a two-photon absorption coefficient of the deposited Ge NCs. The calculated coefficient ranges from 1190 to 1940 cm/GW.
Show PACS
42.70.Nq Other nonlinear optical materials; photorefractive and semiconductor materials
78.67.Bf Nanocrystals, nanoparticles, and nanoclusters
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
42.65.Re Ultrafast processes; optical pulse generation and pulse compression

Real-time three-dimensional surface measurement by color encoded light projection

S. Y. Chen, Y. F. Li, Q. Guan, and G. Xiao

Appl. Phys. Lett. 89, 111108 (2006); http://dx.doi.org/10.1063/1.2352729 (3 pages) | Cited 9 times

Online Publication Date: 12 September 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Existing noncontact methods for surface measurement suffer from the disadvantages of poor reliability, low scanning speed, or high cost. The authors present a method for real-time three-dimensional data acquisition by a color-coded vision sensor composed of common components. The authors use a digital projector controlled by computer to generate desired color light patterns. The unique indexing of the light codes is a key problem and is solved in this study so that surface perception can be performed with only local pattern analysis of the neighbor color codes in a single image. Experimental examples and performance analysis are provided.
Show PACS
42.79.Pw Imaging detectors and sensors
06.30.Bp Spatial dimensions (e.g., position, lengths, volume, angles, and displacements)
42.30.Tz Computer vision; robotic vision

Enhancement of diffraction of dye-doped polymer film assisted with nematic liquid crystals

Chie-Tong Kuo and Shuan-Yu Huang

Appl. Phys. Lett. 89, 111109 (2006); http://dx.doi.org/10.1063/1.2349828 (3 pages) | Cited 1 time

Online Publication Date: 12 September 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The dynamic behavior of surface relief grating of dye-doped polymer film has been under investigation. The enhancement of the first-order diffraction efficiency for dye-doped polymer film can be demonstrated through the use of nematic liquid crystals as the interface. The larger surface modulation of relief grating measured by the atomic force microscopy is consistent with the enhancement of the first-order diffraction efficiency. The time evolution of diffraction efficiency for dye-doped polymer film in contact with nematic liquid crystals shows the pattern of rise-decay-rise to a stable level. The decay of diffraction efficiency is temperature dependent. The pump-probe transmission experiment confirms that the decay of diffraction efficiency is attributed to the inhomogeneous orientation of nematic liquid crystals due to photothermal fluctuation.
Show PACS
42.79.Dj Gratings
78.66.Qn Polymers; organic compounds
42.70.Df Liquid crystals
61.30.-v Liquid crystals
78.20.N- Thermo-optic effects
78.20.nb Photothermal effects

Stable fiber-based Fabry-Pérot cavity

T. Steinmetz, Y. Colombe, D. Hunger, T. W. Hänsch, A. Balocchi, R. J. Warburton, and J. Reichel

Appl. Phys. Lett. 89, 111110 (2006); http://dx.doi.org/10.1063/1.2347892 (3 pages) | Cited 23 times

Online Publication Date: 13 September 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The development of a fiber-based, tunable optical cavity with open access is reported. The cavity is of the Fabry-Pérot type and is formed with miniature spherical mirrors positioned on the end of single- or multimode optical fibers by a transfer technique, which involves lifting a high-quality mirror from a smooth convex substrate, either a ball lens or microlens. The cavities typically have a finesse of ∼ 1000 and a mode volume of 600 μm3. The detection of small ensembles of cold Rb atoms guided through such a cavity on an atom chip is demonstrated.
Show PACS
42.81.Wg Other fiber-optical devices
42.79.Bh Lenses, prisms and mirrors
37.10.Vz Mechanical effects of light on atoms, molecules, and ions
03.75.Be Atom and neutron optics

Efficiency enhancement in Si solar cells by textured photonic crystal back reflector

L. Zeng, Y. Yi, C. Hong, J. Liu, N. Feng, X. Duan, L. C. Kimerling, and B. A. Alamariu

Appl. Phys. Lett. 89, 111111 (2006); http://dx.doi.org/10.1063/1.2349845 (3 pages) | Cited 84 times

Online Publication Date: 13 September 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
An efficient light-trapping scheme is developed for solar cells that can enhance the optical path length by several orders of magnitude using a textured photonic crystal as a backside reflector. It comprises a reflection grating etched on the backside of the substrate and a one-dimensional photonic crystal deposited on the grating. Top-contacted crystalline Si solar cells integrated with the textured photonic crystal back reflector were designed and fabricated. External quantum efficiency was significantly improved between the wavelengths of 1000 and 1200 nm (enhancement up to 135 times), and the overall power conversion efficiency was considerably increased.
Show PACS
84.60.Jt Photoelectric conversion
42.70.Qs Photonic bandgap materials
42.79.Dj Gratings

Fairly pure ultraviolet electroluminescence from ZnO-based light-emitting devices

Peiliang Chen, Xiangyang Ma, and Deren Yang

Appl. Phys. Lett. 89, 111112 (2006); http://dx.doi.org/10.1063/1.2352722 (3 pages) | Cited 36 times

Online Publication Date: 13 September 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Fairly pure ultraviolet (UV) electroluminescence (EL) was realized on a ZnO-based metal-insulator (SiOx,x ⩽ 2)-semiconductor structure on a silicon substrate, which was easily fabricated by the reactive direct current sputtering and electron beam evaporation. The UV EL originated from the near-band-edge (NBE) emission of ZnO was achieved at room temperature when the device was under sufficient forward bias with the negative voltage applied on the silicon substrate. Moreover, the intermediate SiOx layer should be thick enough to confine the electrons in the conduction band of ZnO beneath the ZnO/SiOx interface, which is critical for generation of NBE emission from ZnO.
Show PACS
85.60.Jb Light-emitting devices
85.30.Tv Field effect devices
81.15.Cd Deposition by sputtering
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy

Optical coatings by ion-beam sputtering deposition for long-wave infrared quantum cascade lasers

J. Nguyen, J. S. Yu, A. Evans, S. Slivken, and M. Razeghi

Appl. Phys. Lett. 89, 111113 (2006); http://dx.doi.org/10.1063/1.2353815 (3 pages) | Cited 3 times

Online Publication Date: 13 September 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors report on the development of high-reflection and multilayer antireflection coatings using ion-beam sputtering deposition for long-wave infrared (λ ∼ 9.4 μm) quantum cascade lasers. A metallic high-reflection coating structure using Y2O3 and Au is demonstrated to achieve a high reflectance of 96.70%, and the use of a multilayer anti-reflection coating structure using PbTe and ZnO is demonstrated to achieve a very low reflectance of 1.64%. A 170% improvement of peak laser output power and a 169% increase in wall-plug efficiency are reported without any beam steering effects.
Show PACS
42.79.Wc Optical coatings
81.15.Jj Ion and electron beam-assisted deposition; ion plating
81.15.Cd Deposition by sputtering
42.55.Px Semiconductor lasers; laser diodes

CsBr photocathode at 257 nm: A rugged high current density electron source

Zhi Liu, Juan Maldonado, Yun Sun, Piero Pianetta, and R. F. W. Pease

Appl. Phys. Lett. 89, 111114 (2006); http://dx.doi.org/10.1063/1.2354029 (3 pages) | Cited 9 times

Online Publication Date: 13 September 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
There is a continuing need for high intensity electron sources that will operate in demountable vacuum and can be externally modulated. Materials with wide band gap, e.g., diamond, are rugged but need photon energies exceeding the band gap to emit efficiently and this rules out the use of cw lasers. The authors have found that a photocathode of CsBr is both adequately intense (>150 A/cm2) and rugged and can be excited with photons of energy of 4.8 eV (257 nm). This is below the energy gap of CsBr (7.3 eV) but such operation can be explained by the presence of intraband states about 4 eV below the conduction band minimum.
Show PACS
85.60.Ha Photomultipliers; phototubes and photocathodes

Quenching of Er(III) luminescence by ligand C–H vibrations: Implications for the use of erbium complexes in telecommunications

L. Winkless, R. H. C. Tan, Y. Zheng, M. Motevalli, P. B. Wyatt, and W. P. Gillin

Appl. Phys. Lett. 89, 111115 (2006); http://dx.doi.org/10.1063/1.2345909 (3 pages) | Cited 27 times

Online Publication Date: 14 September 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors have quantified the quenching of the luminescence lifetime of Er3+ ions in organic complexes due to the presence of CH vibrational oscillators as a function of their distance from the ion. They have shown that any hydrogen atoms within a sphere of at least 20 Å from an erbium ion will cause sufficient quenching to prohibit its use in telecommunications applications.
Show PACS
78.55.Kz Solid organic materials
42.70.Jk Polymers and organics

Direct observation of waveguide formation in KGd(WO4)2 by low dose H+ ion implantation

C. A. Merchant, J. S. Aitchison, S. Garcia-Blanco, C. Hnatovsky, R. S. Taylor, F. Agulló-Rueda, A. J. Kellock, and J. E. E. Baglin

Appl. Phys. Lett. 89, 111116 (2006); http://dx.doi.org/10.1063/1.2340496 (3 pages) | Cited 5 times

Online Publication Date: 14 September 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In this letter, a direct measurement of a refractive index change in potassium gadolinium tungstate (KGW) created by a low-dose ion implantation of 1 MeV hydrogen ions is reported. The characterization was performed using both microreflectivity and Raman spectroscopy measurements. The microreflectivity results show both negative and positive changes in refractive index in the damage region when measuring refractive index along different polarization axes. Micro-Raman spectroscopy analysis shows preservation of the Raman characteristics of KGW in the nondamaged crystal regions. These results show that ion implantation in KGW has a great potential for fabricating waveguide structures in Raman-based photonic devices.
Show PACS
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
42.79.Gn Optical waveguides and couplers
42.70.-a Optical materials
61.72.up Other materials
61.80.Jh Ion radiation effects
78.30.Hv Other nonmetallic inorganics

Organic light-emitting device on a scanning probe cantilever

Kwang H. An, Brendan O’Connor, Kevin P. Pipe, Yiying Zhao, and Max Shtein

Appl. Phys. Lett. 89, 111117 (2006); http://dx.doi.org/10.1063/1.2353816 (3 pages) | Cited 7 times

Online Publication Date: 14 September 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Organic light-emitting devices (OLEDs) were fabricated on scanning probe cantilevers using a combination of thermally evaporated molecular organic compounds and metallic electrodes. Ion beam milling was used to define the emissive region in the shape of a ring having a diameter of less than 5 μm and a narrow width. Stable light emission was observed from the device at forward bias, with a current-voltage response similar to that of archetypal OLEDs. Based on this device, a novel electrically pumped scanning optical microscopy tool is suggested.
Show PACS
85.60.Jb Light-emitting devices
85.40.Hp Lithography, masks and pattern transfer
07.79.-v Scanning probe microscopes and components

Lateral light emitting n-i-p diodes in InSb/AlxIn1−xSb quantum wells

S. J. Smith, G. R. Nash, C. J. Bartlett, L. Buckle, M. T. Emeny, and T. Ashley

Appl. Phys. Lett. 89, 111118 (2006); http://dx.doi.org/10.1063/1.2354015 (3 pages) | Cited 4 times

Online Publication Date: 14 September 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Lateral light emitting diodes have been fabricated in InSb/AlxIn1−xSb quantum wells using a simple bevel etching technique. The peak in emission was found to be in the range of 4–5 μm, confirming that the emission was from the quantum well.
Show PACS
85.30.Kk Junction diodes
85.35.Be Quantum well devices (quantum dots, quantum wires, etc.)
81.65.Cf Surface cleaning, etching, patterning

Multimegawatt peak-power, single-transverse-mode operation of a 100 μm core diameter, Yb-doped rodlike photonic crystal fiber amplifier

Christopher D. Brooks and Fabio Di Teodoro

Appl. Phys. Lett. 89, 111119 (2006); http://dx.doi.org/10.1063/1.2348742 (3 pages) | Cited 48 times

Online Publication Date: 15 September 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors report on the performance of an Yb-doped, 100 μm core rodlike photonic crystal fiber (PCF) used as the final amplifier in a gain-staged master-oscillator/power-amplifier source. From the PCF, they obtained 1-ns-long pulses of energy in excess of 4.3 mJ, peak/average power ∼ 4.5 MW/42 W, and spectral linewidth ∼ 20 GHz. The PCF emitted a beam exhibiting near-Gaussian, single-transverse-mode profile of M2 ∼ 1.3.
Show PACS
42.55.Tv Photonic crystal lasers and coherent effects
42.55.Wd Fiber lasers
42.60.By Design of specific laser systems
42.65.Re Ultrafast processes; optical pulse generation and pulse compression
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation

Two- and one-dimensional light propagations and gain in layer-by-layer-deposited colloidal nanocrystal waveguides

J. Roither, S. Pichler, M. V. Kovalenko, W. Heiss, P. Feychuk, O. Panchuk, J. Allam, and B. N. Murdin

Appl. Phys. Lett. 89, 111120 (2006); http://dx.doi.org/10.1063/1.2354433 (3 pages) | Cited 3 times

Online Publication Date: 15 September 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Optical waveguides containing high percentages of colloidal nanocrystals have been fabricated by layer-by-layer deposition on planar and patterned glass substrates. The two- and one-dimensional waveguidings in these structures are demonstrated by propagation loss experiments. The experimental results obtained for various film thicknesses and widths of the waveguide stripes together with simulations of the light propagation indicate that the losses are dominated by surface roughness. The variable stripe length method is used to determine the optical gain of 230 cm−1 from the amplified spontaneous emission. This high value makes the authors’ waveguide structures very promising for applications in amplifiers and lasers with reduced threshold powers.
Show PACS
42.82.Et Waveguides, couplers, and arrays
42.79.Gn Optical waveguides and couplers

Thermal responsive microlens arrays

Han Yang, Yong-Hao Han, Xiang-Wei Zhao, Keiji Nagai, and Zhong-Ze Gu

Appl. Phys. Lett. 89, 111121 (2006); http://dx.doi.org/10.1063/1.2354435 (3 pages) | Cited 5 times

Online Publication Date: 15 September 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors developed a technique to encapsulate poly-N-isopropylacrylamide (PNIPAAm) for fabrication of monodisperse microcapsules, whose size, embedding efficiency, and wall thickness are controllable. The monodisperse microcapsules were hexagonally packed to form microlens array (MLA) via a self-assembly process. Due to the thermal respondence of PNIPAAm, the imaging capability and light transportation of the MLA were simply controlled by temperature.
Show PACS
42.79.Bh Lenses, prisms and mirrors
42.70.Jk Polymers and organics

Table-top soft x-ray imaging of nanometric films

F. Calegari, S. Stagira, C. D’Andrea, G. Valentini, C. Vozzi, M. Nisoli, S. De Silvestri, L. Poletto, P. Villoresi, A. Faenov, and T. Pikuz

Appl. Phys. Lett. 89, 111122 (2006); http://dx.doi.org/10.1063/1.2354469 (3 pages) | Cited 10 times

Online Publication Date: 15 September 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Profiles of nanometric aluminum and parylene foils have been characterized by soft x-ray contact imaging using a laser-plasma source and a LiF crystal as detector. Due to the characteristic emission of this source in a 2π angle, it was possible to obtain the sample image in a wider field of view with respect to coherent sources. LiF crystal is a cheap and robust imaging detector for soft x-ray radiation, that allows one to get high spatial resolution images of thin films with thickness from hundreds down to a few tens of nanometers.
Show PACS
07.85.-m X- and γ-ray instruments
42.79.Wc Optical coatings
42.70.-a Optical materials

Anomalous behavior in the third harmonic generation z response through dispersion induced shape changes and matching χ(3)

Rajesh S. Pillai, G. J. Brakenhoff, and M. Müller

Appl. Phys. Lett. 89, 111123 (2006); http://dx.doi.org/10.1063/1.2354579 (3 pages)

Online Publication Date: 15 September 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The third harmonic generation (THG) axial response in the vicinity of an interface formed by two isotropic materials of normal dispersion is typically single peaked, with the maximum intensity at the interface position. Here it is shown experimentally that this THG z response may show anomalous behavior—being double peaked with a dip coinciding with the interface position—when the THG contributions from both materials are of similar magnitude. The observed anomalous behavior is explained, using paraxial Gaussian theory, by considering dispersion induced shape changes in the THG z response.
Show PACS
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
42.65.An Optical susceptibility, hyperpolarizability

Effect of substrate proximity on luminescence yield from Si nanocrystals

Ilya Sychugov, Augustinas Galeckas, Niklas Elfström, Andrew R. Wilkinson, Robert G. Elliman, and Jan Linnros

Appl. Phys. Lett. 89, 111124 (2006); http://dx.doi.org/10.1063/1.2226976 (3 pages) | Cited 2 times

Online Publication Date: 15 September 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The influence of the proximity of a high refractive index substrate on the luminescence of Si nanocrystals was investigated by time-integrated and time-resolved photoluminescence. The luminescence yield was found to be ∼ 2.5 times larger for emitters distanced from the substrate compared to those in proximity with the substrate, while luminescence decay measurements revealed only a slight increase in the luminescence lifetime ( ∼ 15%). Results are discussed in terms of local density of optical modes surrounding a pointlike light emitter with important implications for the collection efficiency of luminescence and the estimation of internal quantum efficiency for a quantum dot.
Show PACS
78.55.Ap Elemental semiconductors
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
78.47.-p Spectroscopy of solid state dynamics
78.67.Bf Nanocrystals, nanoparticles, and nanoclusters
78.67.Hc Quantum dots
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close