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

29 Jan 2007

Volume 90, Issue 5, Articles (05xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 90, 052503 (2007); http://dx.doi.org/10.1063/1.2436715 (3 pages)

Biqin Huang, Igor Altfeder, and Ian Appelbaum
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Influence of uniaxial stress on stimulated terahertz emission from phosphor and antimony donors in silicon

R. Kh. Zhukavin, V. V. Tsyplenkov, K. A. Kovalevsky, V. N. Shastin, S. G. Pavlov, U. Böttger, H.-W. Hübers, H. Riemann, N. V. Abrosimov, and N. Nötzel

Appl. Phys. Lett. 90, 051101 (2007); http://dx.doi.org/10.1063/1.2431568 (3 pages) | Cited 6 times

Online Publication Date: 29 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The effect of uniaxial stress on terahertz stimulated emission from phosphor and antimony donors in silicon excited by CO2 laser radiation was studied. The laser action originates from 2p0→1s(T2) intracenter transitions. A compressive force applied to the silicon crystal decreases the laser threshold by one order of magnitude. The output power depends nonmonotonically on the stress, while the emission frequency does not change. The results are explained by changes of the donor electronic structure, which do not affect the energy gap between the laser states, and a resonant interaction with acoustic f-TA and g-TA phonons that disappears with increasing stress.
Show PACS
78.45.+h Stimulated emission
63.20.K- Phonon interactions
71.55.Cn Elemental semiconductors
78.70.Gq Microwave and radio-frequency interactions

Ultrashort pulse generation in lasers by nonlinear pulse amplification and compression

L. M. Zhao, D. Y. Tang, T. H. Cheng, and C. Lu

Appl. Phys. Lett. 90, 051102 (2007); http://dx.doi.org/10.1063/1.2437124 (3 pages) | Cited 1 time

Online Publication Date: 29 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Generation of ultrashort, transform-limited pulses in a laser resonator by means of nonlinear pulse amplification and compression is observed both numerically and experimentally; this constitutes another type of pulse shaping mechanism in the mode-locked lasers. It is shown that as a result of nonlinear pulse compression, mode-locked pulse with pulse width beyond the gain bandwidth limitation could be directly generated in a laser.
Show PACS
42.65.Re Ultrafast processes; optical pulse generation and pulse compression
42.60.Fc Modulation, tuning, and mode locking
42.60.Da Resonators, cavities, amplifiers, arrays, and rings

Technique for measuring the rotational velocity of a single cell

Toshiki Yasokawa, Ichirou Ishimaru, Katsumi Ishizaki, Kazuhiro Gesyo, Shigeki Kuriyama, Tsutomu Masaki, Kaoru Takegawa, and Naotaka Tanaka

Appl. Phys. Lett. 90, 051103 (2007); http://dx.doi.org/10.1063/1.2437129 (3 pages)

Online Publication Date: 30 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A method for measuring the rotational velocity of a cell is presented. In this method, a parallel pencil beam illuminates the cell and the reflected light intensity distribution from the cell surface is observed using an objective lens. In the Fourier transform plane of the lens, this light intensity distribution is translated by an amount that corresponds to the rotational velocity of the cell. This translational velocity can be converted into the rotational velocity. The authors confirmed that the rotational velocity of a cell could be measured using this method by rotating a cancer cell using light pressure.
Show PACS
87.63.L- Visual imaging
87.17.-d Cell processes
87.19.X- Diseases
42.30.Kq Fourier optics

Kinetic study of Al-mole fraction in AlxGa1−xN grown on c-plane sapphire and AlN bulk substrates by metal-organic vapor-phase epitaxy

Y. A. Xi, K. X. Chen, F. W. Mont, J. K. Kim, W. Lee, E. F. Schubert, W. Liu, X. Li, and J. A. Smart

Appl. Phys. Lett. 90, 051104 (2007); http://dx.doi.org/10.1063/1.2437681 (3 pages) | Cited 2 times

Online Publication Date: 30 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A systematic study is performed on the dependence of the Al-mole fraction in AlxGa1−xN on the organometallic group-III precursor flow during metal-organic vapor-phase epitaxy. When keeping the total organometallic volume flow constant, a nonlinear concave bowing relationship is found between the Al-mole fraction (for 0 ⩽ x ⩽ 1) and the relative trimethylaluminum volume flow. A kinetic model, which takes into account the growth rate ratio between GaN and AlN (gGaN/gAlN), is developed to explain such concave bowing relationship. The experimental data are in excellent agreement with the theoretical model. For AlxGa1−xN growth on AlN bulk substrates, it is found that the Al-mole fraction is smaller and the growth rate ratio is larger than on sapphire substrates. The authors also investigate the incorporation of Al in AlxGa1−xN as a function of the group-III precursor molar flow rate. A positive convex bowing relationship is found between Al-mole fraction and the relative trimethylaluminum molar flow, which is consistent with our model.
Show PACS
68.55.A- Nucleation and growth
68.55.-a Thin film structure and morphology
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
81.15.Kk Vapor phase epitaxy; growth from vapor phase
81.05.Ea III-V semiconductors

Enhanced photoresponse of a metal-oxide-semiconductor photodetector with silicon nanocrystals embedded in the oxide layer

Jia-Min Shieh, Yi-Fan Lai, Wei-Xin Ni, Hao-Chung Kuo, Chih-Yao Fang, Jung Y. Huang, and Ci-Ling Pan

Appl. Phys. Lett. 90, 051105 (2007); http://dx.doi.org/10.1063/1.2450653 (3 pages) | Cited 13 times

Online Publication Date: 30 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors report a two-terminal metal-oxide-semiconductor photodetector for which light is absorbed in a capping layer of silicon nanocrystals embedded in a mesoporous silica matrix on p-type silicon substrates. Operated at reverse bias, enhanced photoresponse from 300 to 700 nm was observed. The highest optoelectronic conversion efficiency is as high as 200%. The enhancements were explained by a transistorlike mechanism, in which the inversion layer acts as the emitter and trapped positive charges in the mesoporous dielectric layer assist carrier injection from the inversion layer to the contact, such that the primary photocurrent could be amplified.
Show PACS
85.60.Gz Photodetectors (including infrared and CCD detectors)
85.30.Tv Field effect devices

Blue light emitting diodes based on fluorescent CdSe/ZnS nanocrystals

Aurora Rizzo, Yanqin Li, Stefan Kudera, Fabio Della Sala, Marco Zanella, Wolfgang J. Parak, Roberto Cingolani, Liberato Manna, and Giuseppe Gigli

Appl. Phys. Lett. 90, 051106 (2007); http://dx.doi.org/10.1063/1.2426899 (3 pages) | Cited 27 times

Online Publication Date: 30 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors report on the blue electroluminescence from CdSe/ZnS core/shell nanocrystals prepared from ultrasmall, magic size CdSe clusters that have a diameter of less than 2 nm. The light emitting device consists of an active layer of nanocrystals blended with 4,4′,N,N′- diphenylcarbazole and an evaporated electron transporting/hole blocking layer made of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline. A blue, stable electroluminescence at 485 nm from the hybrid device was observed, in good agreement with the photoluminescence spectra of a solid film of the same nanocrystals used for the device.
Show PACS
85.60.Jb Light-emitting devices

Polariton parametric luminescence in a single micropillar

D. Bajoni, E. Peter, P. Senellart, J. L. Smirr, I. Sagnes, A. Lemaître, and J. Bloch

Appl. Phys. Lett. 90, 051107 (2007); http://dx.doi.org/10.1063/1.2435515 (3 pages) | Cited 14 times

Online Publication Date: 31 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors report on parametric luminescence in a single pillar semiconductor microcavity. Nonresonant photoluminescence measurements at 10 K show that micropillars operate in the exciton-photon strong coupling regime. Under resonant excitation, polariton parametric scattering is observed: signal and idler beams are of comparable intensities, a promising result in the framework of quantum optics with correlated photon pairs.
Show PACS
78.67.De Quantum wells
78.55.Cr III-V semiconductors
71.36.+c Polaritons (including photon-phonon and photon-magnon interactions)
71.35.-y Excitons and related phenomena
42.50.-p Quantum optics

Wavelength- and material-dependent absorption in GaAs and AlGaAs microcavities

C. P. Michael, K. Srinivasan, T. J. Johnson, O. Painter, K. H. Lee, K. Hennessy, H. Kim, and E. Hu

Appl. Phys. Lett. 90, 051108 (2007); http://dx.doi.org/10.1063/1.2435608 (3 pages) | Cited 22 times

Online Publication Date: 31 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The quality factors of modes in nearly identical GaAs and Al0.18Ga0.82As microdisks are tracked over three wavelength ranges centered at 980, 1460, and 1600 nm, with quality factors measured as high as 6.62×105 in the 1600 nm band. After accounting for surface scattering, the remaining loss is due to sub-band-gap absorption in the bulk and on the surfaces. The observed absorption is, on average, 80% greater in AlGaAs than in GaAs and is 540% higher in both materials at 980 nm than at 1600 nm.
Show PACS
78.30.Fs III-V and II-VI semiconductors
78.66.Fd III-V semiconductors

Extrahigh color rendering white light-emitting diode lamps using oxynitride and nitride phosphors excited by blue light-emitting diode

Naoki Kimura, Ken Sakuma, Syunichiro Hirafune, Kenichiro Asano, Naoto Hirosaki, and Rong-Jun Xie

Appl. Phys. Lett. 90, 051109 (2007); http://dx.doi.org/10.1063/1.2437090 (3 pages) | Cited 69 times

Online Publication Date: 1 February 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The blue-light-excitation-type white light-emitting diode (LED) lamps are considered to be very suitable for lighting for art objects, shop window displays, and medical applications because they do not give infrared ray and ultraviolet ray. But their color rendering indices are needed to be improved for such applications. In this letter, the authors have fabricated white LED lamps with a broad range of color temperatures, and realized extrahigh color rendering index Ra values of 95–98 in them, using four oxynitride/nitride phosphors and a blue LED die. It means UV LED die is not always necessary for high color rendering white LED lamps. The luminous efficacies of white LED lamps are 28–35 lm/W, which are sufficiently high for extremely high color rendering white LED lamps.
Show PACS
85.60.Jb Light-emitting devices
42.72.Bj Visible and ultraviolet sources

Excitation dynamics of the 1.54 μm emission in Er doped GaN synthesized by metal organic chemical vapor deposition

C. Ugolini, N. Nepal, J. Y. Lin, H. X. Jiang, and J. M. Zavada

Appl. Phys. Lett. 90, 051110 (2007); http://dx.doi.org/10.1063/1.2450641 (3 pages) | Cited 20 times

Online Publication Date: 1 February 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors report on the excitation dynamics of the photoluminescence (PL) emission of Er doped GaN thin films synthesized by metal organic chemical vapor deposition. Using the frequency tripled output from a Ti:sapphire laser, the authors obtained PL spectra covering the ultraviolet (UV) to the infrared regions. In the UV, a dominant band edge emission at 3.23 eV was observed at room temperature; this is redshifted by 0.19 eV from the band edge emission of undoped GaN. An activation energy of 191 meV was obtained from the thermal quenching of the integrated intensity of the 1.54 μm emission line. This value coincides with the redshift of the band edge emission and is assigned to the ErGa-VN complex level.
Show PACS
78.66.Fd III-V semiconductors
78.55.Cr III-V semiconductors
81.40.Gh Other heat and thermomechanical treatments
42.70.Nq Other nonlinear optical materials; photorefractive and semiconductor materials

Short-wavelength (λ ≈ 3.05 μm) InP-based strain-compensated quantum-cascade laser

M. P. Semtsiv, M. Wienold, S. Dressler, and W. T. Masselink

Appl. Phys. Lett. 90, 051111 (2007); http://dx.doi.org/10.1063/1.2437108 (3 pages) | Cited 35 times

Online Publication Date: 2 February 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The design and implementation of a short-wavelength quantum-cascade laser based on the strain-compensated In0.73Ga0.27As–In0.55Al0.45As–AlAs heterosystem on InP is described. Lasers with a reduced level of doping in the active region require a larger bias voltage and emit at shorter wavelength; the emission wavelength is 3.05 μm at T ≈ 80 K. The lasers operate up to T ≈ 150 K and electroluminescence persists up to room temperature, where the peak position is close to 3.3 μm. The short-wavelength limit of such lasers is evaluated based on the dependence of their maximum operation temperatures and on the probable energies of the indirect valleys in the active region.
Show PACS
42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems

Excitation dependences of gain and carrier-induced refractive index change in quantum-dot lasers

M. Lorke, F. Jahnke, and W. W. Chow

Appl. Phys. Lett. 90, 051112 (2007); http://dx.doi.org/10.1063/1.2437670 (3 pages) | Cited 10 times

Online Publication Date: 2 February 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The excitation-density dependence of optical gain and refractive index changes in quantum-dot active media is investigated on the basis of a microscopic theory. Carrier-carrier Coulomb interaction and carrier-phonon interaction are treated on the level of a quantum-kinetic description. In the range of small optical gain the authors find small values of the α factor, while in the regime of gain saturation ∣α∣ increases drastically.
Show PACS
42.55.Px Semiconductor lasers; laser diodes
63.20.K- Phonon interactions
63.22.-m Phonons or vibrational states in low-dimensional structures and nanoscale materials
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)

Off-axis directional beaming of optical field diffracted by a single subwavelength metal slit with asymmetric dielectric surface gratings

Seyoon Kim, Hwi Kim, Yongjun Lim, and Byoungho Lee

Appl. Phys. Lett. 90, 051113 (2007); http://dx.doi.org/10.1063/1.2437730 (3 pages) | Cited 48 times

Online Publication Date: 2 February 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors propose a method for the off-axis directional beaming of optical field diffracted by a single subwavelength metal slit with dielectric surface gratings. In the proposed method, dielectric gratings are optimally designed to directionally couple the surface plasmon polariton modes induced by the metal slit into surrounding medium along a specific off-axis direction. Design of the gratings and the analysis are conducted based on the rigorous coupled wave analysis method. Their simulation shows the off-axis directional beaming of the oblique angle, 20.2°, with respect to the on axis by the proposed method. The beaming angle can be changed by adjusting the grating periods.
Show PACS
42.79.Gn Optical waveguides and couplers
42.79.Dj Gratings
42.15.Eq Optical system design
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
71.36.+c Polaritons (including photon-phonon and photon-magnon interactions)

Measured limits of detection based on thermal-mechanical frequency noise in micromechanical sensors

T. H. Stievater, W. S. Rabinovich, N. A. Papanicolaou, R. Bass, and J. B. Boos

Appl. Phys. Lett. 90, 051114 (2007); http://dx.doi.org/10.1063/1.2450643 (3 pages) | Cited 6 times

Online Publication Date: 2 February 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors have fabricated and tested all-optical micromechanical resonators that sense the presence of analyte molecules by monitoring the shift in the resonant frequency of a mechani-cal mode of vibration. An analysis of the measured frequency noise at the fundamental flexural mode shows that it is dominated by thermal-mechanical noise. This result demonstrates that thermal-mechanical frequency noise can set the limit of detection in actual micromechanical or nanomechanical resonance-based sensors.
Show PACS
85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
82.80.-d Chemical analysis and related physical methods of analysis

High power continuous-wave green light generation by quasiphase matching in Mg stoichiometric lithium tantalate

Sergey V. Tovstonog, Sunao Kurimura, and Kenji Kitamura

Appl. Phys. Lett. 90, 051115 (2007); http://dx.doi.org/10.1063/1.2450648 (3 pages) | Cited 27 times

Online Publication Date: 2 February 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Single-pass second-harmonic generation of 7 W continuous wave of 542 nm radiation with 35.4% efficiency was achieved by quasiphase matching in periodically poled Mg-doped stoichiometric lithium tantalate at room temperature. The effects of laser beam quality and linewidth on the second-harmonic generation efficiency were investigated using a Yb-doped fiber laser.
Show PACS
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
42.70.Mp Nonlinear optical crystals
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
77.80.-e Ferroelectricity and antiferroelectricity
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)

Viewing angle switching of vertical alignment liquid crystal displays by controlling birefringence of homogenously aligned liquid crystal layer

Eun Jeong, Young Jin Lim, John Moon Rhee, Seung Hee Lee, Gi-Dong Lee, Kyoung Ho Park, and Hyun Chul Choi

Appl. Phys. Lett. 90, 051116 (2007); http://dx.doi.org/10.1063/1.2435693 (3 pages) | Cited 24 times

Online Publication Date: 2 February 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Viewing angle switching from a wide viewing angle to a narrow viewing angle has been studied. Conventional multidomain vertical alignment (VA) mode offers the advantages of a high contrast ratio (CR) not only in the front view but also in the wide viewing directions only if compensation films such as a negative C plate and a positive A plate are used. The positive A plate can be replaced by a homogeneous aligned (HA) liquid crystal layer, and the retardation of the HA layer at the off axis can be controlled by applying an electric field while keeping the retardation value at zero in the normal direction. Consequently, the viewing angle range of a VA device can be controlled from a wide viewing mode (over 170° in terms of CR = 10) to a narrow viewing angle mode (approximately 60° in terms of CR = 2) in the horizontal direction while keeping a high image quality at the normal direction.
Show PACS
42.79.Kr Display devices, liquid-crystal devices
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close