Arrays of gold single-strip and double-strip nano-antennas, with resonance in the wavelength range of 1200-1600 nm, were fabricated on the top of InGaAs/InP multi quantum well structure. Photo-luminescence from the quantum-wells was measured and shown to be enhanced by a factor of up to 9, with maximum enhancement wavelength corresponding to the nano-antennas resonance. Emission enhancement is attributed to the coupling of emitting charge-carriers to the plasmonic nano-antennas, causing an estimated increase in the radiative recombination rate by a factor of ~25, thus making it dominant over non-radiative recombination. This effect will enable fast modulation of InP-based nano-emitters spontaneously emitting at telecom-wavelength.

Arrays of plasmonic nano-antennas were fabricated on InGaAs/InP multi quantum well structure. Photo-luminescence enhancement of x9 was measured in correspondence with nano-antennas resonance, attributed to x25 increase in radiative recombination rate.

In many plasmonic waveguides – modes are determined by the complex coupling of wedges within the structure. We examine systematically the mode stemming from wedge coupling and subsequently validate experimentally the generation of such modes.

Measurements of a W-shaped metal-coated surface Plasmon polariton waveguides are presented, showing complex confined modes both in the coupled pair of air filled metal V-grooves, as well as within the central metal-coated triangular silicon wedge. Mode calculations support the experimentally measured plasmonic modes. Such W-shaped plasmonic waveguides when integrated with Metal-Oxide-Silicon structures may be utilized for active plasmonic nano-optical devices.

A 50 nm diameter gold cylinder loaded on a semiconductor surface creates sub-wavelength field confinement in 3D. The virtual nano-cavity exhibits 180 nm modal volume with Q-factor of few hundreds, suitable for realizing a semiconductor based nano-laser.

Measurements of W-shaped metal-coated silicon plasmon waveguide exhibit confined modes in both silicon-metal wedge and air-metal V-grooves. The highly confined mode in silicon is included in design for high efficiency fast CMOS based plasmonic modulator.

The seamless transition between microscale photonics and nanoscale plasmonics requires overpassing different waveguiding mechanisms and a few orders of magnitude in the lateral dimension. Exploiting gap plasmon-polariton waves both at the microscale and nanoscale with an ultrashort (few micrometers) nonadiabatic tapered gap plasmon waveguide, we show theoretically that very high-power transfer efficiency (approximately 70%) is achieved. The same mechanism may be used to harvest impinging light waves and direct them into a nanohole or slit to exhibit an anomalous transmission without the conventional periodic structures. The interplay of plasmonic and oscillating modes is analyzed.

An ultrashort (2.5 microns) tapered plasmon waveguide coupler with overall 70% coupling efficiency from a micron size dielectric waveguide to a 50 nm metal-clad plasmon waveguide was proposed, and related plasmonic-oscillatory modes interactions were investigated.

Efficient interfacing (>60% efficiency) between micro-scale waveguides and nanoscale plasmon waveguides is achieved by an ultrashort (6 microns) tapered gap plasmon waveguide. The Interplay of related plasmonic and oscillating modes is analyzed.

We have explored theoretically and experimentally the steady-state transverse light fields emitted from ring-shaped lasers, specifically, those from vertical-cavity surface-emitting lasers (VCSELs). We saw the switching on of patterns of increasing spatial frequencies as a function of pump parameter. Furthermore, we were able to identify the mechanism for such an evolution as geometrical modulational instability within the nonlinear cavity. Other mechanisms such as the conventional gain-loss balance had no effect on the ring configuration that was modeled. The experiments with annular VCSELs gave results that matched the theoretical predictions well, although other mechanisms not considered in our model, such as carrier diffusion, took place in the experimental devices. We conclude that the nonlinear mechanisms presented here can be regarded as limiting cases in the interpretation of more-complex functions, such as patterns, modes, and filamentation switching, in VCSELs. (C) 2002 Optical Society of America.

A hybrid 40 GHz semiconductor pulse generating laser suitable for long-haul RZ (return-to-zero) transmission was constructed, emitting 5.5 ps pulses of >22 dB contrast ratio, and with a BER performance equivalent to a less compact EA modulator based transmitter. The actively mode-locked hybrid laser consists of a specially designed two gain section semiconductor laser chip coupled to an external fiber Bragg-grating (FBG).

The formation of a variety of stable complex transverse light patterns in nonlinear optical cavities was studied both in one and two dimensions [1-3]. A laser, which is based on a nonlinear resonator, can emit spontaneously some of these patterns [3,4].

We show that the basic on-switching of spatial patterns (modes) in lasers is a result of an intrinsic nonlinear dynamical effect-the modulation instability (MI) of the self consistent field patterns in the complex nonlinear medium-and present the threshold conditions for the formation of the patterns (modes). We emphasis a ring shaped laser-having no “hard ” boundary conditions-which makes it the best system to exhibit the “clean” phenomena both experimentally and theoretically. A vertical cavity surface-emitting laser (VCSEL) is a semiconductor laser with a 2-dimensional resonator and thus is ideal for the implementation of ring shaped laser with periodic boundary conditions in the azimuthal coordinate

The generation of stable dense soliton trains in passively mode locked ring fiber lasers was explored theoretically. We found equilibrium states of even and odd numbers of interacting solitons in a ring configuration by employing soliton perturbation theory. In a lossless ring, these equilibrium states were unstable due to the lack of a damping mechanism both for the oscillations in the solitons parameters as well as for modulation instability. In a passively mode-locked ring fiber laser, these dense soliton trains were self-stabilized to form ordered trains. The stabilization process was initiated by the local repulsive soliton-soliton interactions and preceeded by a global soliton phase locking stemming from multimode self-injection locking. We describe in detail the evolution from a disordered to ordered dense soliton train

We show that as a result of spatial solitons in a ring VCSEL has two thresholds - the first is the lasing threshold and the second is the solitonic threshold, where the VCSEL switches to be a soliton laser. We modeled the evolution of spatial solitons in the semiconductor laser medium using the 1D wave equation which is applicable for large enough ring shaped lasers

Periodic nanosecond pulses of microwave radiation were observed from a low-pressure magnetic-field-free hollow-cathode discharge. These microwave spikes were emitted when the discharge current exceeded the threshold for the periodic collapse of the cathode sheath, each collapse cycle corresponding to one spike. The spikes were found to appear at the same phase of the collapse cycle. The peak power of each spike was about 10 W. A wide frequency spectrum was observed above the electron plasma frequency of the discharge plasma, ranging from a few GHz up to at least 20 GHz.

calculated dependency of IVBA on the hole density being in very good agreement with absorption measurements on p-GaAs.',' At T = 300 K andp = 10" ~ m ~ , the calculated IVBA coefficients of GaAs are a(1.55 pm) = 33 cm-' with dddp(1.55 pm) = 3.4 X ~ m ~ a n d a ( 1 . 3 pm) = 16cm-'withda/dp(l.3 pm) = 1.6 X cm2. The temperature dependency will be discussed. Free carrier absorption (intraband transitions within one vamagnitude at A = 1.55 pm. Figure 2 shows the WEDNESDAY AFTERNOON / CLE0'97 / 235

Large circular VCSELs exhibit spontaneous transition from vertical to almost in-plane, quasi whispering gallery lasing modes. Enhancing this effect by coupling to concentric ring VCSELs is demonstrated and analyzed.