There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Microcavity physics and design will be reviewed. Following an overview of applications in quantum optics, communications and biosensing, recent advances in ultra-high-Q research will be presented.

Optical microcavities

The term photonic crystals appears because of the analogy between electron waves in crystals and the light waves in artificial periodic dielectric structures. During the recent years the investigation of one-, two-and three-dimensional periodic structures has attracted a widespread attention of the world optics community because of great potentiality of such structures in advanced applied optical fields. The interest in periodic structures has been stimulated by the fast development of semiconductor technology that now allows the fabrication of artificial structures, whose period is comparable with the wavelength of light in the visible and infrared ranges.

http://ieeexplore.ieee.org/iel5/6354/16969/00781867.pdf

Photonic crystals

The electronic and optical properties and the recent progress in applications of 2D semiconductor transition metal dichalcogenides with emphasis on strong excitonic effects, and spin- and valley-dependent properties are reviewed. Recent advances in the development of atomically thin layers of van der Waals bonded solids have opened up new possibilities for the exploration of 2D physics as well as for materials for applications. Among them, semiconductor transition metal dichalcogenides, MX2 (M = Mo, W; X = S, Se), have bandgaps in the near-infrared to the visible region, in contrast to the zero bandgap of graphene. In the monolayer limit, these materials have been shown to possess direct bandgaps, a property well suited for photonics and optoelectronics applications. Here, we review the electronic and optical properties and the recent progress in applications of 2D semiconductor transition metal dichalcogenides with emphasis on strong excitonic effects, and spin- and valley-dependent properties.

Photonics and optoelectronics of 2D semiconductor transition metal dichalcogenides

Several InP based samples with a single InAs QDash layer embedded in In/sub 0.528/Al/sub 0.238/Ga/sub 0.234/As were grown with various dash sizes to investigate the dependence of the emission intensity and wavelength on the dash layer thickness. Photoluminescence measurements at 8 K show a good control over the emission wavelength between 1.15 /spl mu/m and 1.9 /spl mu/m. In addition, uncapped QDash layers were grown to study the QDash formation by secondary electron microscopy. These results were used to combine four QDash layers with slightly different thicknesses to distribute the gain homogeneously over a larger spectral range. With this technique a flat gain profile of over 300 nm was confirmed by photoluminescence spectroscopy.

http://ieeexplore.ieee.org/iel5/9837/30998/01442620.pdf

Tailored InP-based quantum dash structures for ultra-wide gain bandwidth applications

Amorphous chalcogenide (As2Se3)100-x(AgI)x thin films with x = 5, 10, 15, 20, 25, 30 and 35 mol % have been deposited by pulsed laser deposition (PLD) and vacuum thermal evaporation (VTE). The films were characterized by various techniques with respect to their structure, composi- tion and morphology. The optical properties were studied by transmission spectroscopy; the optical band gap Eg was determined from Tauc plots and as Eg 04 in the strong absorption region (by α ≥10 4 cm −1 ) from the relation- ship α  (hν). The variation of the band gap is discussed with respect to the influence of the AgI content and the methods of film preparation.

Study of (As2Se3)100-X(AgI)X Thin Films Prepared by Pld and Vte Methods

During the European project, BIGBAND, we have developed 1.55 μm quantum dash Fabry-Perot lasers based on InP using a ridge waveguide operating in continuous wave at room temperature. These devices have not only reached a high power of 50mW per facet but also have shown an ultra low relative intensity noise (RIN) of -162 dB/Hz ± 1.6 dB/Hz in 0.1-13 GHz range for the first year. At the end of the project we have succeeded in obtaining a very low RIN of -160 dB/Hz ± 2 dB/Hz over a wide bandwidth from 50 MHz to 18 GHz. 
This paper deals with the analysis of the experimental results, obtained with quantum dash Fabry Perot lasers, especially those relating to noise performances and also the first results of reliability demonstrating the suitability of these new devices for microwave optical links.

Ultra-low noise over wide-bandwidth of 1.55 μm InP-based quantum-dash Fabry-Perot lasers for microwave systems

An overview is given on recent progress of InP-based quantum dots and photonic elements addressing the 1.55 pm wavelength range for far distance fiber-based quantum optical communication. Specific growth and fabrication techniques as well as fundamental physical quantum properties are discussed.

Telecom Wavelength Nanophotonic Elements for Quantum Communication

Starting with a short historical synopsis this paper gives a brief introduction into semiconductor lasers. The working principles and the necessary fabrication technology are examined. Semiconductor laser systems offer unique characteristics, rendering them superior to other types of lasers. By combining different compound semiconductors a huge range of wavelengths spanning from ultra-violet (UV) to the far-infrared (FIR) can be covered. Hence, by applying sophisticated bandgap and photonic engineering, tailored far-infrared lasers are able to address a vast amount of applications. The existing semiconductor laser technology is suitable to meet the requirements of highly sensitive optical sensing for various applications.

Johann Peter Reithmaier

Papers

Tailored InP-based quantum dash structures for ultra-wide gain bandwidth applications

Study of (As2Se3)100-X(AgI)X Thin Films Prepared by Pld and Vte Methods

Ultra-low noise over wide-bandwidth of 1.55 μm InP-based quantum-dash Fabry-Perot lasers for microwave systems

Telecom Wavelength Nanophotonic Elements for Quantum Communication

Semiconductor Lasers for Sensor Applications