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

A review was presented to demonstrate a historical description of the synthesis of light-emitting conjugated polymers for applications in electroluminescent devices. Electroluminescence (EL) was first reported in poly(para-phenylene vinylene) (PPV) in 1990 and researchers continued to make significant efforts to develop conjugated materials as the active units in light-emitting devices (LED) to be used in display applications. Conjugated oligomers were used as luminescent materials and as models for conjugated polymers in the review. Oligomers were used to demonstrate a structure and property relationship to determine a key polymer property or to demonstrate a technique that was to be applied to polymers. The review focused on demonstrating the way polymer structures were made and the way their properties were controlled by intelligent and rational and synthetic design.

Synthesis of Light-Emitting Conjugated Polymers for Applications in Electroluminescent Devices

Industry 4.0: A Survey on Technologies, Applications and Open Research Issues

The discovery of the enhancement of Raman scattering by molecules adsorbed on nanostructured metal surfaces is a landmark in the history of spectroscopic and analytical techniques. Significant experimental and theoretical effort has been directed toward understanding the surface-enhanced Raman scattering (SERS) effect and demonstrating its potential in various types of ultrasensitive sensing applications in a wide variety of fields. In the 45 years since its discovery, SERS has blossomed into a rich area of research and technology, but additional efforts are still needed before it can be routinely used analytically and in commercial products. In this Review, prominent authors from around the world joined together to summarize the state of the art in understanding and using SERS and to predict what can be expected in the near future in terms of research, applications, and technological development. This Review is dedicated to SERS pioneer and our coauthor, the late Prof. Richard Van Duyne, whom we lost during the preparation of this article.

/pdf/present-and-future-of-surface-enhanced-raman-scattering-34aqgcm385.pdf

Present and Future of Surface-Enhanced Raman Scattering

Supersymmetric Dark Matter

The modification and control of exciton–photon interactions in semiconductors is of both fundamental1,2,3,4 and practical interest, being of direct relevance to the design of improved light-emitting diodes, photodetectors and lasers5,6,7. In a semiconductor microcavity, the confined electromagnetic field modifies the optical transitions of the material. Two distinct types of interaction are possible: weak and strong coupling1,2,3,4. In the former perturbative regime, the spectral and spatial distribution of the emission is modified but exciton dynamics are little altered. In the latter case, however, mixing of exciton and photon states occurs leading to strongly modified dynamics. Both types of effect have been observed in planar microcavity structures in inorganic semiconductor quantum wells and bulk layers1,2,3,4,5,6,7,8. But organic semiconductor microcavities have been studied only in the weak-coupling regime9,10,11,12,13,14,15,16,17,18. Here we report an organic semiconductor microcavity that operates in the strong-coupling regime. We see characteristic mixing of the exciton and photon modes (anti-crossing), and a room-temperature vacuum Rabi splitting (an indicator of interaction strength) that is an order of magnitude larger than the previously reported highest values for inorganic semiconductors. Our results may lead to new structures and device concepts incorporating hybrid states of organic and inorganic excitons19, and suggest that polariton lasing20,21,22 may be possible.

Strong exciton–photon coupling in an organic semiconductor microcavity

We report a room temperature study of the strong exciton-photon coupling regime in a planar microcavity, containing cyanine dye aggregates with delocalized exciton wave functions ( $J$ aggregates). Giant Rabi splittings of 80 meV between upper and lower polariton branches are observed and cavity polariton emission is detected from the lower polariton branch. The small linewidth and large oscillator strength characteristic of $J$ aggregates make them a favorable physical structure to allow the observation of strong coupling for organic semiconductors.

Room Temperature Polariton Emission from Strongly Coupled Organic Semiconductor Microcavities

Vertical-cavity electrically driven lasers with three GaInAs quantum wells and diameters of several μm exhibit roomtemperature pulsed current thresholds as low as 1·3mA with 958 nm output wavelength.

Low-Threshold Electrically Pumped Vertical Cavity Surface-Emitting Microlasers

Vertical-cavity electrically driven lasers with three GaInAs
quantum wells and diameters of several μm exhibit room-temperature pulsed current thresholds as low as 1.3mA with 958 nm output wavelength.

Low-Threshold Electrically Pumps Vertical-Cavity Surface-Emitting Microlasers

We demonstrate successful transmission of 4-Gbps uncompressed video over a 60-GHz orbital angular momentum (OAM) wireless channel. Matlab simulation was employed to support the experimental work and to generate the holographic masks used. Matlab coding is a unique approach which can produce any desired shape on copper or dielectric plates by mean of a commercial routing tool. We believe this is the first reported transmission of 4-Gbps uncompressed video over the 60-GHz OAM wireless channel. Good agreement was achieved between the simulated and measured results. Practical opportunities for multi-gigabit future wireless communications are available.

Stuart D. Walker

Papers

Strong exciton–photon coupling in an organic semiconductor microcavity

Room Temperature Polariton Emission from Strongly Coupled Organic Semiconductor Microcavities

Low-Threshold Electrically Pumped Vertical Cavity Surface-Emitting Microlasers

Low-Threshold Electrically Pumps Vertical-Cavity Surface-Emitting Microlasers

4-Gbps Uncompressed Video Transmission over a 60-GHz Orbital Angular Momentum Wireless Channel