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

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue

28 Jun 1999

Volume 74, Issue 26, pp. 3921-4070

Return to All Sections
back to top
RSS Feeds

Surface-mode lasing from stacked InGaN insertions in a GaN matrix

A. V. Sakharov, W. V. Lundin, I. L. Krestnikov, V. A. Semenov, A. S. Usikov, A. F. Tsatsul’nikov, Yu. G. Musikhin, M. V. Baidakova, Zh. I. Alferov, N. N. Ledentsov, A. Hoffmann, and D. Bimberg

Appl. Phys. Lett. 74, 3921 (1999); http://dx.doi.org/10.1063/1.124224 (3 pages) | Cited 13 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report surface-mode lasing in a structure with 12-fold stacked InGaN insertions in a GaN matrix without using of Bragg mirrors. At high excitation densities, one of the modes of the Fabry–Perot cavity formed by the GaN sapphire and the GaN air interfaces, shows a strong superlinear increase in intensity with excitation density rise. The possibility to reach surface lasing in a very low finesse microcavity is due to the ultrahigh material gain of the InGaN insertions. The strong modulation of the absorption-gain spectrum with increase in the excitation density results in a pronounced energy shift of the cavity modes. We found that the threshold excitation density is weakly affected by temperature up to 110 K, while increases at higher temperatures. This behavior is attributed to thermal evaporation of carriers from InN-rich nanodomains and is typical for quantum dot lasers. © 1999 American Institute of Physics.
Show PACS
42.60.By Design of specific laser systems
42.55.Px Semiconductor lasers; laser diodes
42.60.Da Resonators, cavities, amplifiers, arrays, and rings

A microscope for hard x rays based on parabolic compound refractive lenses

B. Lengeler, C. G. Schroer, M. Richwin, J. Tümmler, M. Drakopoulos, A. Snigirev, and I. Snigireva

Appl. Phys. Lett. 74, 3924 (1999); http://dx.doi.org/10.1063/1.124225 (3 pages) | Cited 75 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We describe refractive x-ray lenses with a parabolic profile that are genuine imaging devices, similar to glass lenses for visible light. They open considerable possibilities in x-ray microscopy, tomography, microanalysis, and coherent scattering. Based on these lenses a microscope for hard x rays is described, that can operate in the range from 2 to 50 keV, allowing for magnifications up to 50. At present, it is possible to image an area of about 300 μm in diameter with a resolving power of 0.3 μm that can be increased to 0.1 μm. This microscope is especially suited for opaque samples, up to 1 cm in thickness, which do not tolerate sample preparation, like many biological and soil specimens. © 1999 American Institute of Physics.
Show PACS
07.85.Tt X-ray microscopes
87.64.-t Spectroscopic and microscopic techniques in biophysics and medical physics

Two-photon absorption in semiconductor saturable absorber mirrors

E. R. Thoen, E. M. Koontz, M. Joschko, P. Langlois, T. R. Schibli, F. X. Kärtner, E. P. Ippen, and L. A. Kolodziejski

Appl. Phys. Lett. 74, 3927 (1999); http://dx.doi.org/10.1063/1.124226 (3 pages) | Cited 24 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The nonlinear reflectivity of semiconductor saturable absorber mirrors has been investigated as a function of incident energy fluence. The presence of two-photon absorption in commonly used structures was confirmed via time-resolved differential reflectivity measurements. Theoretical calculations predict that two-photon absorption will expand the continuous-wave mode-locking stability regime against Q-switched mode-locking, yet may simultaneously induce multiple pulses in a laser cavity. © 1999 American Institute of Physics.
Show PACS
42.50.Md Optical transient phenomena: quantum beats, photon echo, free-induction decay, dephasings and revivals, optical nutation, and self-induced transparency
42.79.Bh Lenses, prisms and mirrors
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.60.Fc Modulation, tuning, and mode locking
78.47.-p Spectroscopy of solid state dynamics

Indium tin oxide contacts to gallium nitride optoelectronic devices

T. Margalith, O. Buchinsky, D. A. Cohen, A. C. Abare, M. Hansen, S. P. DenBaars, and L. A. Coldren

Appl. Phys. Lett. 74, 3930 (1999); http://dx.doi.org/10.1063/1.124227 (3 pages) | Cited 85 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have fabricated GaN-based light-emitting diodes using transparent indium tin oxide (ITO) p contacts. ITO-contacted devices required an additional 2 V to drive 10 mA, as compared to similar devices with metal contacts. However, ITO has lower optical absorption at 420 nm (α = 664 cm−1) than commonly used thin metal films (α = 3×105 cm−1). Uniform luminescence was observed in ITO-contacted devices, indicating effective hole injection and current spreading. © 1999 American Institute of Physics.
Show PACS
85.60.Jb Light-emitting devices
73.40.Cg Contact resistance, contact potential

Optical photonic crystals fabricated from colloidal systems

G. Subramania, K. Constant, R. Biswas, M. M. Sigalas, and K.-M. Ho

Appl. Phys. Lett. 74, 3933 (1999); http://dx.doi.org/10.1063/1.124228 (3 pages) | Cited 78 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Photonic crystals of close-packed arrays of air spheres in a dielectric background of titania have been fabricated with a ceramic technique. Unlike previous methods, ordering of the spheres and the formation of the titania network are performed simultaneously. The photonic crystals exhibit a reflectance peak and a uniform color at the position of the first stop band. The wavelength of the reflectance peak scales very well with the sphere size. © 1999 American Institute of Physics.
Show PACS
42.70.Qs Photonic bandgap materials
82.70.Dd Colloids

Bifunctional molecular glass for efficient photorefractive material

Kenji Ogino, Sang-Hun Park, and Hisaya Sato

Appl. Phys. Lett. 74, 3936 (1999); http://dx.doi.org/10.1063/1.124229 (3 pages) | Cited 17 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Two bifunctional succinates have been prepared as molecular photorefractive materials, which contain a hole-transporting triphenylamine moiety and an electro-optically active chromophore. The synthesized succinates formed stable amorphous glasses at room temperature. Succinate with 4-dicyanovinylaniline moiety as an electro-optic chromophore showed excellent photorefractive properties, i.e., 65% of diffraction efficiency, and 188 cm−1 of two-beam coupling gain at 60 V/μm, which are comparable to that observed in one of the most efficient photorefractive polymers. © 1999 American Institute of Physics.
Show PACS
42.70.Nq Other nonlinear optical materials; photorefractive and semiconductor materials
42.70.Ce Glasses, quartz
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close