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

5 Apr 2004

Volume 84, Issue 14, pp. 2473-2706

Issue Cover Spotlight Figure

Appl. Phys. Lett. 84, 2244 (2004); http://dx.doi.org/10.1063/1.1690471 (3 pages)

David R. Smith, David Schurig, Jack J. Mock, Pavel Kolinko, and Patrick Rye
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Microsecond time scale lateral-mode dynamics in a narrow stripe InGaN laser

Christoph Eichler, Daniel Hofstetter, Weng W. Chow, Stephan Miller, Andreas Weimar, Alfred Lell, and Volker Härle

Appl. Phys. Lett. 84, 2473 (2004); http://dx.doi.org/10.1063/1.1691497 (3 pages) | Cited 9 times

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Time-resolved measurements of the spectrum and the far field of InGaN-based laser diodes show lateral-mode changes and gradual tilting of the far field on a microsecond time scale. Numerical simulations based on a microscopic theory are in good agreement with the measurements. The observed effects are attributed to lateral carrier diffusion in combination with thermal lensing. © 2004 American Institute of Physics.
Show PACS
42.60.By Design of specific laser systems
78.47.-p Spectroscopy of solid state dynamics
78.66.Fd III-V semiconductors
85.30.De Semiconductor-device characterization, design, and modeling
42.55.Ah General laser theory

Polymer electrophosphorescence devices with high power conversion efficiencies

X. H. Yang and D. Neher

Appl. Phys. Lett. 84, 2476 (2004); http://dx.doi.org/10.1063/1.1691194 (3 pages) | Cited 92 times

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate efficient single-layer polymer phosphorescent light-emitting devices based on a green-emitting iridium complex and a polymer host co-doped with electron-transporting and hole-transporting molecules. These devices can be operated at relatively low voltages, resulting in a power conversion efficiency of up to 24 lm/W at luminous efficiencies exceeding 30 cd/A. The overall performances of these devices suggest that efficient electrophosphorescent devices with acceptable operating voltages can be achieved in very simple device structures fabricated by spin coating. © 2004 American Institute of Physics.
Show PACS
85.60.Jb Light-emitting devices
78.55.Kz Solid organic materials

Thermal-flow technique for reducing surface roughness and controlling gap size in polymer microring resonators

Chung-Yen Chao and L. Jay Guo

Appl. Phys. Lett. 84, 2479 (2004); http://dx.doi.org/10.1063/1.1691492 (3 pages) | Cited 16 times

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Q factors of microring resonator waveguide devices are primarily limited by the surface-roughness-induced scattering loss. Such surface roughness loss has been observed in waveguides that are fabricated from various types of materials, including semiconductors, dielectrics, and polymers. In this letter, we show that the surface roughness of polymer waveguides can be greatly reduced by a thermal-flow technique, and the effective reduction in waveguide loss was verified experimentally. In addition to smoothing surfaces, this technique can simultaneously shrink the gap distance in the coupling region of polymer microring resonators. This, in turn, provides higher coupling, lessens the difficulty of fabricating submicron gaps, and leads to more compact devices. © 2004 American Institute of Physics.
Show PACS
42.79.Gn Optical waveguides and couplers

1.31 μm InGaAs quantum dot light-emitting diodes grown directly in a GaAs matrix by metalorganic chemical-vapor deposition

M. T. Todaro, M. De Giorgi, V. Tasco, M. De Vittorio, R. Cingolani, and A. Passaseo

Appl. Phys. Lett. 84, 2482 (2004); http://dx.doi.org/10.1063/1.1687979 (3 pages) | Cited 11 times

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We investigate the optical properties of light-emitting diodes (LEDs) operating at 1.3 μm embedding, in the intrinsic region, quantum dots (QDs) directly grown by metalorganic chemical-vapor deposition in a GaAs matrix, without indium in the barrier. The device characterization shows a full width at half maximum of the ground state emission as narrow as 24 meV at room temperature and a quenching of the emission between 30 K and room temperature as low as 2.75. Despite the low dot density (1.6×109 cm−2), the external quantum efficiency of our devices is 0.03%. This indicates that the individual QD efficiency of our devices is about 30% higher than that reported in the literature for state of the art InGaAs/InGaAs QD LEDs. © 2004 American Institute of Physics.
Show PACS
78.67.Hc Quantum dots
78.60.Fi Electroluminescence
78.55.Cr III-V semiconductors
85.60.Jb Light-emitting devices
68.65.Hb Quantum dots (patterned in quantum wells)
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)

Current-injection spiral-shaped microcavity disk laser diodes with unidirectional emission

M. Kneissl, M. Teepe, N. Miyashita, N. M. Johnson, G. D. Chern, and R. K. Chang

Appl. Phys. Lett. 84, 2485 (2004); http://dx.doi.org/10.1063/1.1691494 (3 pages) | Cited 47 times

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A spiral-shaped microcavity heterojunction laser diode fabricated with InGaN multiple quantum wells is demonstrated to operate under current injection conditions and emit unidirectionally. Room-temperature laser operation was achieved for microcavity disk radii ranging from 50 to 350 μm and threshold current densities as low as 4.6 kA/cm2. Unidirectional laser emission is clearly revealed in the far-field pattern with the lateral divergence angle ranging from 60° to 75°. Output power of more than 25 mW was obtained for emission wavelengths near 400 nm. © 2004 American Institute of Physics.
Show PACS
42.55.Sa Microcavity and microdisk lasers

Optically pumped ultraviolet microdisk laser on a silicon substrate

X. Liu, W. Fang, Y. Huang, X. H. Wu, S. T. Ho, H. Cao, and R. P. H. Chang

Appl. Phys. Lett. 84, 2488 (2004); http://dx.doi.org/10.1063/1.1695090 (3 pages) | Cited 31 times

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have fabricated ultraviolet microdisk lasers on silicon substrates. A thin layer of zinc oxide is grown on top of the silica microdisks and serves as the gain medium. Under optical pumping, lasing occurs in the whispering gallery modes of the hybrid microdisks at room temperature. Above the lasing threshold, a drastic increase of emission intensity is accompanied by a decrease of spectral width of the lasing modes. © 2004 American Institute of Physics.
Show PACS
42.55.Sa Microcavity and microdisk lasers
42.55.Px Semiconductor lasers; laser diodes

Phototunable photonic bandgap in a chiral liquid crystal laser device

Seiichi Furumi, Shiyoshi Yokoyama, Akira Otomo, and Shinro Mashiko

Appl. Phys. Lett. 84, 2491 (2004); http://dx.doi.org/10.1063/1.1699445 (3 pages) | Cited 57 times

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This letter describes the phototunable photonic bandgap of cholesteric liquid crystal (CLC) doped with a fluorescent dye to generate the distributed feedback effect. Photoirradiation of the dye-doped CLC cell under UV light at 254 nm resulted in continuous changes in the chiral photonic bandgap from 550 to 720 nm due to photolysis reaction of the cholesteryl iodide embedded in the CLC host. We showed that the laser oscillation wavelength could be controlled in a wide wavelength range from 610 to 700 nm by photoassisted adjustment of CLC photonic bandgaps. © 2004 American Institute of Physics.
Show PACS
42.55.Tv Photonic crystal lasers and coherent effects
42.70.Qs Photonic bandgap materials
42.70.Df Liquid crystals
78.40.Dw Liquids
82.50.Hp Processes caused by visible and UV light
42.79.Kr Display devices, liquid-crystal devices

Continuous-wave operation of terahertz quantum-cascade lasers above liquid-nitrogen temperature

Sushil Kumar, Benjamin S. Williams, Stephen Kohen, Qing Hu, and John L. Reno

Appl. Phys. Lett. 84, 2494 (2004); http://dx.doi.org/10.1063/1.1695099 (3 pages) | Cited 81 times

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report cw operation of a quantum-cascade laser at 3.2 THz (λ≈94 μm) up to a heat-sink temperature of 93 K. Resonant longitudinal-optical phonon scattering is used to depopulate the lower radiative state and a low-loss metal–metal waveguide is used to provide high modal confinement. Optical powers of ∼1.8 mW at 10 K and ∼400 μW at 78 K are observed from a single facet of a 40-μm-wide and 1.35-mm-long laser device. A threshold current density of 432 A/cm2 at 10 K and 552 A/cm2 at 78 K was obtained in cw mode. The same device lased up to 129 K in pulsed mode with a threshold current density of 419 A/cm2 at 5 K. © 2004 American Institute of Physics.
Show PACS
42.60.By Design of specific laser systems
42.55.Px Semiconductor lasers; laser diodes

Anticrossing between heavy-hole states in Si0.2Ge0.8/Si-coupled quantum wells grown on Si0.5Ge0.5 pseudosubstrate

L. Diehl, A. Borak, S. Mentese, D. Grützmacher, H. Sigg, U. Gennser, I. Sagnes, Y. Campidelli, O. Kermarrec, D. Bensahel, and J. Faist

Appl. Phys. Lett. 84, 2497 (2004); http://dx.doi.org/10.1063/1.1691173 (3 pages) | Cited 1 time

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Intersubband absorption measurements were performed on a single repetition of coupled Si0.2Ge0.8/Si quantum wells grown on a Si0.5Ge0.5 pseudosubstrate. Two resonances observed at low temperature are identified with the optical transitions between the ground and the first excited heavy-hole states confined in the coupled wells through their anticrossing behavior. The measured coupling energy agrees well with calculated values. In addition, the Stark shift of a diagonal resonance between a heavy- and light-hole level was observed. © 2004 American Institute of Physics.
Show PACS
73.21.Fg Quantum wells
78.67.De Quantum wells
42.50.Hz Strong-field excitation of optical transitions in quantum systems; multiphoton processes; dynamic Stark shift
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close