Volume 87, Issue 1, 01 January 2000
Index of content:
- LASERS, OPTICS, AND OPTOELECTRONICS (PACS 42)
Series resistance and its effect on the maximum output power of 1.5 μm strained-layer multiple-quantum-well ridge waveguide InGaAsP lasers87(2000); http://dx.doi.org/10.1063/1.371817View Description Hide Description
The series resistance of InGaAsP/InP multiple quantum well ridge waveguide laserdiodes is investigated experimentally over a wide temperature range for both Fabry–Perot and distributed feedback type lasers. From the temperature dependence of the series resistance is found that it is defined mostly by the resistance of heterobarriers, although the semiconductor bulk resistance is also found to be a substantial part of ridge waveguide laser series resistance. The effect of the laser series resistance on other performance characteristics also investigated. The theoretically predicted strong correlation between the series resistance and laser maximum operating power is confirmed experimentally. The ways of reducing of series resistance are discussed.
Finite-cell-gap corrections to the capacitance analysis of liquid crystal displays with periodic interdigital electrodes87(2000); http://dx.doi.org/10.1063/1.371818View Description Hide Description
Corrections to the capacitance analysis of liquid crystal displays with periodic interdigital electrodes are presented, accounting for the finite thickness of the liquid crystal(LC) cell gap. Conformal mapping calculations of the corrected equivalent dielectric constant for the LCmaterial and glass substrate are carried out in terms of the aperture ratio, cell gap and LC effective dielectric constant. Departure from the infinite-cell-gap approximation occurs as the gap thickness approaches the electrode width, or the aperture ratio approaches unity. The capacitance–voltage characteristic curve obtained from the conformal mapping calculations is very close to that obtained from the two-dimensional simulations with less than 5% deviation.
A scalar variational method for resonant modes of oxide-apertured vertical-cavity surface-emitting lasers87(2000); http://dx.doi.org/10.1063/1.371819View Description Hide Description
A scalar variational method for calculating the mode sizes and resonant wavelengths of the eigenmodes in oxide-apertured vertical-cavity surface-emitting lasers is presented. This method uses Hermite–Gaussian functions to approximate the transverse-field variations of the eigenmodes. It is applicable to devices with circular, square, or rectangular apertures. Calculated results for the four lowest-order modes show that aperture size, thickness, and axial position are important factors in determining the blueshift in resonant wavelengths, wavelength separation between eigenmodes, and mode sizes. When the geometric symmetry is broken, as in rectangular-apertured devices, the degeneracy between the and is also lifted. For validation of the model presented, three vertical-cavity surface-emitting laserstructures with different oxide thicknesses were grown and fabricated for this study. The resonant wavelength characteristics of near-square and rectangular devices were assessed. The theoretical results are found to agree well with the experimental observations.
87(2000); http://dx.doi.org/10.1063/1.371820View Description Hide Description
The optical properties of lead formate crystals are investigated, especially those affecting the usage for optical second-harmonic generation. The refractive indexes and the optical absorption are measured in the near-ultraviolet, visible, and near-infraredspectral regions. The data show that the material is suitable for the efficient generation of blue light when pumped with near-infrared laser wavelengths. Phase matching conditions for this application of lead formate are determined both experimentally and by a numerical evaluation of the index data.
87(2000); http://dx.doi.org/10.1063/1.371821View Description Hide Description
The materials, and serving as Q switches with an glass laser at 1.54 μm have been demonstrated and analyzed. The output pulses were typically 15–65 ns in duration and of 1–4 mJ depending on the doping concentration and the crystal quality. The ground-state absorption cross section of Co:ZnS has been determined to be and for Co:ZnSe, by bleaching experiments.