We present models for the optical functions of 11 metals used as mirrors and contacts in optoelectronic and optical devices: noble metals (Ag, Au, Cu), aluminum, beryllium, and transition metals (Cr, Ni, Pd, Pt, Ti, W). We used two simple phenomenological models, the Lorentz-Drude (LD) and the Brendel-Bormann (BB), to interpret both the free-electron and the interband parts of the dielectric response of metals in a wide spectral range from 0.1 to 6 eV. Our results show that the BB model was needed to describe appropriately the interband absorption in noble metals, while for Al, Be, and the transition metals both models exhibit good agreement with the experimental data. A comparison with measurements on surface normal structures confirmed that the reflectance and the phase change on reflection from semiconductor-metal interfaces (including the case of metallic multilayers) can be accurately described by use of the proposed models for the optical functions of metallic films and the matrix method for multilayer calculations.

Optical properties of metallic films for vertical-cavity optoelectronic devices.

The role of extended and point defects, and key impurities such as C, O, and H, on the electrical and optical properties of GaN is reviewed. Recent progress in the development of high reliability contacts, thermal processing, dry and wet etching techniques, implantation doping and isolation, and gate insulator technology is detailed. Finally, the performance of GaN-based electronic and photonic devices such as field effect transistors, UV detectors, laser diodes, and light-emitting diodes is covered, along with the influence of process-induced or grown-in defects and impurities on the device physics.

Gan : processing, defects, and devices

1. Introduction and overview 2. Film stress and substrate curvature 3. Stress in anisotropic and patterned films 4. Delamination and fracture 5. Film buckling, bulging and peeling 6. Dislocation formation in epitaxial systems 7. Dislocation interactions and strain relaxation 8. Equilibrium and stability of surfaces 9. The role of stress in mass transport.

Thin Film Materials: Stress, Defect Formation and Surface Evolution

The ability to control the modes oscillating within a laser resonator is of fundamental importance. In general, the presence of competing modes can be detrimental to beam quality and spectral purity, thus leading to spatial as well as temporal fluctuations in the emitted radiation. We show that by harnessing notions from parity-time (PT) symmetry, stable single–longitudinal mode operation can be readily achieved in a system of coupled microring lasers. The selective breaking of PT symmetry can be used to systematically enhance the maximum attainable output power in the desired mode. This versatile concept is inherently self-adapting and facilitates mode selectivity over a broad bandwidth without the need for other additional intricate components. Our experimental findings provide the possibility to develop synthetic optical devices and structures with enhanced functionality.

http://science.sciencemag.org/content/sci/346/6212/975.full.pdf

Parity-time–symmetric microring lasers

In this review article a comprehensive analysis of the developments in ultraviolet (UV) detector technology is described. At the beginning, the classification of UV detectors and general requirements imposed on these detectors are presented. Further considerations are restricted to modern semiconductor UV detectors, so the basic theory of photoconductive and photovoltaic detectors is presented in a uniform way convenient for various detector materials. Next, the current state of the art of different types of semiconductor UV detectors is presented. Hitherto, the semiconductor UV detectors have been mainly fabricated using Si. Industries such as the aerospace, automotive, petroleum, and others have continuously provided the impetus pushing the development of fringe technologies which are tolerant of increasingly high temperatures and hostile environments. As a result, the main efforts are currently directed to a new generation of UV detectors fabricated from wide band‐gap semiconductors the most promising ...

Semiconductor ultraviolet detectors

This is a review article on a stable quartz oscillator. In April 1933, Issac Koga of Tokyo Institute of Technology reported R1 cut quartz crystal plates having a zero temperature coefficient of frequency. This invention was used at first for radio transmitters and later on for clocks. Today, this type of temperature-insensitive quartz crystal oscillator has proven indispensable to all radio communication systems and much of information electronics.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2016RS006053

Invention of temperature-insensitive quartz oscillation plate enabling highly stable communications and clocks: Review of Issac Koga's works

Growth of GaInAs(P)/InP multi-quantum barrier by chemical beam epitaxy

Summary form only given. The vertical-cavity surface-emitting laser (VCSEL) is considered as a key device for Gigabit LAN and optical parallel interconnects. For such high-speed data transmission, a completely single mode VCSEL in terms of transverse/longitudinal mode and polarization state is needed to avoid excess intensity noise and other instabilities. Most of VCSELs grown on [100] substrates show unstable polarization states due to isotropic material gain and symmetric cavity structures. Therefore, several methods for controlling polarization have been considered. On the other hand, the VCSEL grown on GaAs [311] substrate can provide a very stable polarization state. Single transverse mode and polarization mode controlled VCSELs by using [311]B substrate have recently been realized for aforementioned applications. In this paper, we review the technologies for polarization control of VCSELs and then will feature some characteristics of [311]B devices.

http://ieeexplore.ieee.org/iel5/6638/17705/00834483.pdf

Polarization controlled vertical cavity surface emitting lasers

Summary form only given. We have fabricated a 400 nm square micro-aperture VCSEL with single transverse mode operation. We carried out the near field characterization using a sharpened fiber probe. The FWHM of intensity below threshold was 250 nm, and our metal micro-aperture VCSEL may have a potential for a high resolution optical head.

Near-field characterization of micro-aperture surface emitting laser for near field data storage

Summary form only given. Monolithic integration of semiconductor photonic devices is one of key issues for future lightwave networks. Size reduction of photonic devices including semiconductor lasers is important for large scale integration. In this work, we have developed semiconductor micro-fabrication processes to realize miniature photonic devices such as micro-ring lasers and tiny corner reflectors. The design and the characterization on etched facet resonators fabricated by reactive ion beam etching (RIBE) will be presented. We use the total internal reflection at the interface between semiconductors and air to confine the lightwave in the miniature photonic devices. For this purpose, we have fabricated some etched facet resonators.

Kenichi Iga

Papers

Invention of temperature-insensitive quartz oscillation plate enabling highly stable communications and clocks: Review of Issac Koga's works

Growth of GaInAs(P)/InP multi-quantum barrier by chemical beam epitaxy

Polarization controlled vertical cavity surface emitting lasers

Near-field characterization of micro-aperture surface emitting laser for near field data storage

Etched facet semiconductor resonators fabricated by reactive ion beam etching for micro-photonic integrated circuits