597 research outputs found
Evaluation scheme for the design of high power single mode vertical-cavity surface-emitting lasers
A very simple and efficient evaluation procedure is suggested for the design
of high power single mode VCSELs by reviewing the physical mechanisms that
governs mode transition and simplifying the computation steps. In addition, the
new structures are proposed and tested following the suggested evaluation
procedure. As a result, the proposed design exhibits much better stability of
the fundamental mode over a current range wider than the conventional one.Comment: 6 pages, submitted to "optics express
Numerical analysis of high-index nanocomposite encapsulant for light-emitting diodes
We used two-dimensional Finte-Difference-Time-Domain (FDTD) software to study
the transition behavior of nano-particles from scatterers to an optically
uniform medium. We measured the transmission efficiency of the dipole source,
which is located in the high refractive index medium(index=2.00) and
encapsulated by low index resin(index=1.41). In an effort to compose
index-matched resin and to reduce internal reflection, high-index
nano-particles are added to low-index resin in simulations of various sizes and
densities. As the size of the nano-particles and the average spacing between
particles are reduced to 0.02 lambda and 0.07 lambda respectively, the
transmission efficiency improves two-fold compared to that without
nanoparticles. The numerical results can be used to understand the optical
behavior of nano-particles and to improve the extraction efficiency of high
brightness light-emitting-diodes(LEDs), through the use of nano-composite
encapsulant.Comment: 9 pages, 5 jpg figure
Analysis of a metallic nano-rod polarizer using finite-difference-time-domain method
The polarization behavior of metallic nano-rods has been analyzed by means of
the finite-difference-time-domain method. When the average spacing between the
nano-rods is less than a half wavelength, the layer reflects the light
polarized parallel to the nano-rods, as in a nano-slit. However, when the
spacing is larger than a half wavelength, the metallic surface absorbs the
light, polarized perpendicular to the rods, leading to a polarization reversal.
Multiple layers of nano-rods can make a polarizer with a high extinction ratio
and good transmittance
- …