The development of optical gain in chemically synthesized semiconductor nanoparticles (nanocrystal quantum dots) has been intensely studied as the first step toward nanocrystal quantum dot lasers. We examined the competing dynamical processes involved in optical amplification and lasing in nanocrystal quantum dots and found that, despite a highly efficient intrinsic nonradiative Auger recombination, large optical gain can be developed at the wavelength of the emitting transition for close-packed solids of these dots. Narrowband stimulated emission with a pronounced gain threshold at wavelengths tunable with the size of the nanocrystal was observed, as expected from quantum confinement effects. These results unambiguously demonstrate the feasibility of nanocrystal quantum dot lasers.

http://science.sciencemag.org/content/sci/290/5490/314.full.pdf

Optical gain and stimulated emission in nanocrystal quantum dots.

Influences on the semiconductor laser properties of external optical feedback, i.e., return of a portion of the laser output from a reflector external to the laser cavity, have been examined. Experimental observations with a single mode laser is presented with analysis based on a compound cavity laser model, which has been found to explain essential features of the experimental results. In particular, it has been demonstrated that a laser with external feedback can be multistable and show hysteresis phenomena, analogous to those of non-linear Fabry-Perot resonator. It has also been shown that the dynamic properties of injection lasers are significantly affected by external feedback, depending on interference conditions between returned light and the field inside the laser diode.

External optical feedback effects on semiconductor injection laser properties

Slow light with a remarkably low group velocity is a promising solution for buffering and time-domain processing of optical signals. It also offers the possibility for spatial compression of optical energy and the enhancement of linear and nonlinear optical effects. Photonic-crystal devices are especially attractive for generating slow light, as they are compatible with on-chip integration and room-temperature operation, and can offer wide-bandwidth and dispersion-free propagation. Here the background theory, recent experimental demonstrations and progress towards tunable slow-light structures based on photonic-band engineering are reviewed. Practical issues related to real devices and their applications are also discussed. The unique properties of wide-bandwidth and dispersion-free propagation in photonic-crystal devices have made them a good candidate for slow-light generation. This article gives the background theory of slow light, as well as an overview of recent experimental demonstrations based on photonic-band engineering.

/pdf/slow-light-in-photonic-crystals-59fjoaj79v.pdf

Slow light in photonic crystals

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

An overview of analog microwave photonics will be presented. The performance requirements for externally-modulated analog microwave photonic links will be reviewed with specific emphasis placed on modulator efficiency, laser noise, detected photocurrent, and link linearity.

http://ieeexplore.ieee.org/iel5/6387506/6403300/06403360.pdf

Microwave photonics

An analysis and experimental results are described for the automatic polarization control of the polarization plane of the output light from a single-mode fiber with a standard axisymmetric core. This automatic polarization control device consists of two phase shifters made of z-cut LiNbO3 exhibiting the electrooptic effect. The phase shifters are oriented with their transverse planes inclined to each other. The state of the polarization is detected by two Rochon prisms and is fed back to the phase shifters. The analysis has been done for the change of the polarization of the incident light in the polarization control device. The range of the voltage applied to the phase shifter for the control and the condition of the angle between the phase shifters are clarified. Next, experiments have been performed and the single polarization control in the desired direction has been attained. A proposal is made to simplify the control mechanism.

Light polarization control due to electrooptic effect

Linewidth Enhancement Factor of Distributed Reflector (DR) DSM Laser

http://ieeexplore.ieee.org/iel5/5/31087/01446932.pdf

Equivalent relation for wave theory of the Gunn diode using the negative mobility and the distribution function model

Direct modulation properties of bundle-integrated-guide dynamic single mode (BIG-DSM) lasers

A novel resonant electron transfer triode (RETT), which uses electron resonant tunneling utilizing a metal insulator multilayer superlattice as an artificial semiconductor, is proposed and its basic properties are estimated theoretically. Possibility for high speed response in room temperature, such as response time \tau = 0.25-0.38 ps, cutoff frequency f_{T} = 420-640 GHz, maximum oscillation frequency f_{\max} = 530-610 GHz, and the common-emmitter current gain \beta = 8- 34 are expected theoretically with the transverse area of 1000 × 1000 A2and the total base length of 30-100 A. It is also shown theoretically that this triode has common transistor static characteristics.

Yasuharu Suematsu

Papers

Light polarization control due to electrooptic effect

Linewidth Enhancement Factor of Distributed Reflector (DR) DSM Laser

Equivalent relation for wave theory of the Gunn diode using the negative mobility and the distribution function model

Direct modulation properties of bundle-integrated-guide dynamic single mode (BIG-DSM) lasers

Analysis of novel resonant electron transfer triode device using metal-insulator superlattice for high speed response