摘要:

We review the family of optoelectronic devices whose performance is enhanced by placing the active device structure inside a Fabry‐Perot resonant microcavity. Such resonant cavity enhanced (RCE) devices benefit from the wavelength selectivity and the large increase of the resonant optical field introduced by the cavity. The increased optical field allows RCE photodetector structures to be thinner and therefore faster, while simultaneously increasing the quantum efficiency at the resonant wavelengths. Off‐resonance wavelengths are rejected by the cavity making RCE photodetectors promising for low crosstalk wavelength division multiplexing (WDM) applications. RCE optical modulators require fewer quantum wells so are capable of reduced voltage operation. The spontaneous emission spectrum of RCE light emitting diodes (LED) is drastically altered, improving the spectral purity and directivity. RCE devices are also highly suitable for integrated detectors and emitters with applications as in optical logic and in communication networks. This review attempts an encyclopedic overview of RCE photonic devices and systems. Considerable attention is devoted to the theoretical formulation and calculation of important RCE device parameters. Materials criteria are outlined and the suitability of common heteroepitaxial systems for RCE devices is examined. Arguments for the improved bandwidth in RCE detectors are presented intuitively, and results from advanced numerical simulations confirming the simple model are provided. An overview of experimental results on discrete RCE photodiodes, phototransistors, modulators, and LEDs is given. Work aimed at integrated RCE devices, optical logic and WDM systems is also covered. We conclude by speculating what remains to be accomplished to implement a practical RCE WDM system. ©1995 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.360322

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A T‐shaped field‐effect transistor, made out of a pair of two‐dimensional electron gases, is modeled and studied. A simple numerical model is developed to study the electron distribution versus applied gate voltage for different gate lengths. The model is then improved to account for depletion and the width of the two‐dimensional electron gases. The results are then compared to the experimental ones and to some approximate analytical calculations and are found to be in good agreement with them. ©1995 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.360323

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A self‐consistent integral formulation of Green’s functions in thermal wave‐physics is presented in one, two, and three dimensions and for infinite, semi‐infinite, and spatially bounded geometries. Furthermore, several applications are explicitly worked out based on either Dirichlet or Neumann boundary conditions and resulting in well‐known or novel integral expressions for propagating thermal‐wave fields in thermally homogeneous media and in experimentally useful geometries. It is hoped that the Green’s functions methodologies will enhance their use by investigators who wish to take advantage of their elegance, mathematical simplicity, and computational power. ©1995 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.360724

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The scattering from a thin conducting wire is computed by representing the induced current as a sum of driven and resonant terms, the latter with complex propagation constantmkperturbed from its free space valuek. Using Galerkin’s method, the central problem of determiningmreduces to a minimization problem. For the limiting cases of highly conducting or highly absorbing wires simplifications are found. For short wires the Rayleigh cross sections are obtained; for longer wires with high absorption, accurate cross section formulas are constructed based on the unperturbed infinite wire currents. For general wire lengths and conductivities the method is computationally very simple and results are in excellent agreement with independent computations of both current and far field quantities, as well as experimental measurements. ©1995 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.360324

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The electromagnetic field at all points near a high‐voltage transmission line is determined in analytical form. Account is taken of the presence of the earth below the three‐wire, three‐phase power line. The electric and magnetic fields, the total axial current, and the current and power densities in the interior of a human body are determined when the body is standing on the ground under or near the line, is in an elevated basket under the line, or is reclining in bed near the height of the line. The fields are very weak and the current and power densities so small that thermal effects are ignorable, but not necessarily possible effects on nerve action, the functioning of cells, or on certain secretions. ©1995 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.360325

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The space‐charge region that is induced in a semiconductor half‐space by an external point charge is analyzed. The mathematical model gives rise to a free‐boundary problem, since the edge of the space‐charge region [a surfacez=z(d) in cylindrical coordinates] is unknown. From the formal solution of Poisson’s equation, an integral equation forz(d) is derived and approximately solved. The solution describes the depletion region in dependence of the magnitude of the point charge, the charge‐semiconductor distance, and the doping and dielectric constant of the semiconductor. Approximate expressions are derived for the force acting on the point charge and are used to estimate the electrostatic force between the tip and a silicon sample in a scanning force microscope. The limitations of the model are discussed and its generalization to the case of a semiconductor coated by a dielectric film is outlined. ©1995 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.360326

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Optical and lasing characteristics of a rare‐earth‐doped nonlinear crystal, neodymium‐doped lithium tantalate (Nd:LiTaO3), have been studied. Continuous wave lasing lines at 1.092 and 1.082 &mgr;m with ordinary (&sgr;) and extraordinary (&pgr;) polarizations, respectively, have been observed by pumping near the 800 nm absorption region. The effects of annealing and poling of the crystal on the fluorescence spectrum, lifetime, and polarization are investigated. A comparative study of the slope efficiency and threshold for ordinary and extraordinary polarized lasing is also made. ©1995 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.360327

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We present an overview of a cross‐sectional scanning microphotoluminescence technique that is used to examine various buried‐layer semiconductor structures for which traditional surface‐normal techniques cannot yield sufficient information or must be coupled with time‐consuming and painstaking processes such as wet etching. This technique has a wide range of applications; two—defect‐driven interdiffusion in quantum wells and the modification of spontaneous emission from quantum wells in vertical‐cavity surface‐emitting lasers (VCSELs)—are discussed here. The data obtained using this method can be used to distinguish emission spectra from quantum wells as little as one micrometer apart in depth and a few nanometers different in wavelength. The comparison of normal incidence with cross‐sectional data from VCSELs can be used to more effectively optimize the match between cavity resonance and quantum well emission in high‐Qdevices. ©1995 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.360328

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A model for cw laser induced mode‐mismatched dual‐beam thermal lens spectrometry using probe beam profile detection has been developed. This model exhibits the following behavior: after passing through the thermal lens the TEM00Gaussian probe beam becomes the superposition of several Gaussian beams of different parameters. This model has a compact mathematical expression, for which experimental proofs are given. ©1995 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.360329

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A novel nonlinear optical amino acid derivative,L‐pyrrolidone‐2‐carboxylic acid (L‐PCA), has been studied for the application of UV generation by frequency upconversion of laser radiation.L‐PCA is relatively easy to grow from solution to a large size, typically ∼40×20×20 mm3, by a slow cooling method. This crystal is chemically stable because the crystal lattice is composed of a network of hydrogen‐bonded molecules.L‐PCA has a wide transparency extending to the UV region (the cutoff wavelength is 260 nm) and is therefore a good candidate for the second‐harmonic generation (SHG) of Nd:YAG laser radiation (1064 nm). The nonlinear‐optical coefficientd14was measured to be 0.22 pm/V, and the measured phase‐matching angles agreed with values calculated using refractive index data. The effective nonlinear optical coefficientdeffof the type‐I phase‐matched SHG has also been measured to be 0.20 pm/V. UV generation down to 266 nm was achieved by phase‐matched SHG inL‐PCA crystals. ©1995 American Institute of Physics. 

ISSN:0021-8979    

DOI:10.1063/1.360330

出版商:AIP    

年代:1995

数据来源: AIP