Alexandros Emboras

Nanoscale Plasmonic Memristor with Optical Readout Functionality

We experimentally demonstrate for the first time a nanoscale resistive random access memory (RRAM) electronic device integrated with a plasmonic waveguide providing the functionality of optical readout. The device fabrication is based on silicon on insulator CMOS compatible approach of local oxidation of silicon, which enables the realization of RRAM and low optical loss channel photonic waveguide at the same fabrication step. This plasmonic device operates at telecom wavelength of 1.55 μm and can be used to optically read the logic state of a memory by measuring two distinct levels of optical transmission. The experimental characterization of the device shows optical bistable behavior between these levels of transmission in addition to well-defined hysteresis. We attribute the changes in the optical transmission to the creation of a nanoscale absorbing and scattering metallic filament in the amorphous silicon layer, where the plasmonic mode resides.

Electrically Controlled Plasmonic Switches and Modulators

Plasmonic modulators and switches have recently attracted considerable attention because they offer ultracompact size, high bandwidths, and potentially low-power consumption. In this paper, we review and compare the current state of the art of plasmonic switches and discuss the various physical phenomena that are used to perform efficient switching. More precisely, we discuss plasmonic devices based on the thermal effect, the free carrier dispersion effect, the Pockels effect, phase change materials and switching caused by electrochemical metallization.

Atomic Scale Plasmonic Switch

The atom sets an ultimate scaling limit to Moores law in the electronics industry. While electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling, similar to electronics, is only limited by the atom. More precisely, we introduce an electrically controlled plasmonic switch operating at the atomic scale. The switch allows for fast and reproducible switching by means of the relocation of an individual or, at most, a few atoms in a plasmonic cavity. Depending on the location of the atom either of two distinct plasmonic cavity resonance states are supported. Experimental results show reversible digital optical switching with an extinction ratio of 9.2 dB and operation at room temperature up to MHz with femtojoule (fJ) power consumption for a single switch operation. This demonstration of an integrated quantum device allowing to control photons at the atomic level opens intriguing perspectives for a fully integrated and highly scalable chip platform, a platform where optics, electronics, and memory may be controlled at the single-atom level.The atom sets an ultimate scaling limit to Moores law in the electronics industry. And while electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling-similar to electronics-is only limited by the atom. More precisely, we introduce an electrically controlled single atom plasmonic switch. The switch allows for fast and reproducible switching by means of the relocation of an individual or at most -- a few atoms in a plasmonic cavity. Depending on the location of the atom either of two distinct plasmonic cavity resonance states are supported. Experimental results show reversible digital optical switching with an extinction ration of 10 dB and operation at room temperature with femtojoule (fJ) power consumption for a single switch operation. This demonstration of a CMOS compatible, integrated quantum device allowing to control photons at the single-atom level opens intriguing perspectives for a fully integrated and highly scalable chip platform -- a platform where optics, electronics and memory may be controlled at the single-atom level.

Plasmonic Organic Hybrid Modulators—Scaling Highest Speed Photonics to the Microscale

Complementing plasmonic slot waveguides with highly nonlinear organic materials has rendered a new generation of ultracompact active nanophotonic components that are redefining the state of the art. In this paper, we review the fundamentals of this so-called plasmonic- organic-hybrid (POH) platform. Starting from simple phase shifters to the most compact IQ modulators, we introduce key devices of high-speed data communications. For instance, all-plasmonic Mach-Zehnder modulators (MZMs) are reviewed and long-term prospects are discussed. This kind of modulator already features unique properties such as a small footprint (<; 20 μm2), a large electro-optic bandwidth (> 110 GHz), a small energy consumption (~25 fJ/b), a large extinction ratio (> 25 dB) in combination with a record small voltage-length product of 40 Vμm. Finally, as an example for seamless integration we introduce novel plasmonic IQ modulators. With such modulators we show the generation of advanced modulation formats (QPSK, 16-QAM) on footprints as small as 10 μm × 75 μm. This demonstration ultimately shows how plasmonics can be used to control both phase and amplitude of an optical carrier on the microscale with reasonably low losses.

Ultra-compact plasmonic IQ-modulator

Plasmonic IQ-modulators with a record small footprint are demonstrated to operate up to 72 GBd. The devices have shown the ability to encode QPSK and 16-QAM modulation formats with power consumption as low as 27 fJ/bit at 18 GBd-16QAM.

Optical memristive switches

Optical memristive switches are particularly interesting for the use as latching optical switches, as a novel optical memory or as a digital optical switch. The optical memristive effect has recently enabled a miniaturization of optical devices far beyond of what seemed feasible. The smallest optical – or plasmonic – switch has now atomic scale and in fact is switched by moving single atoms. In this review, we summarize the development of optical memristive switches on their path from the micro- to the atomic scale. Three memristive effects that are important to the optical field are discussed in more detail. Among them are the phase transition effect, the valency change effect and the electrochemical metallization.

Plasmonic devices for communications

Plasmonic modulators and detectors are the building blocks of a new generation of ultra-fast and ultra-compact optical interconnects. In this paper we review some of the recent successes towards the realization of a plasmonic interconnect solution.

Plasmonic modulators and switches (Conference Presentation)

A rich variety of plasmonic modulators and switches is emerging. They offer ultra-compact size in the order of a few micrometers, bandwidths from the MHz to the THz, low power consumption and they operate across a large spectral range. Some plasmonic devices are latching and others offer linear performance. Plasmonic devices not only come in a variety of shapes but also rely on various physical phenomena such as the thermal effect, the free carrier dispersion effect, the Pockels effect, the material phase change effect or they may rely on electrochemical metallization effects. After a discussion on the physics of plasmonics we will conclude the talk with a discussion of the opportunities and challenges related to plasmonics in optical communications and in particular with respect to applications in optical interconnects.

Atomic scale plasmonic devices

The arrival of the Single-Atom Transistor (SAT) in 2004, a quantum device operated at room temperature, allowed for the first controlled switching of an electrical current by the reproducible relocation of one single metal atom [1]. At the same time this component established the feasibility of transistors completely made of metals. Meanwhile, many experiments have followed, demonstrating the control of this three-terminal device on the atomic level and even showing a first simple integrated circuit [2]-[4]. A comparable device for plasmonic switching has not been realized yet. However, the fact that this Single Atom Transistor is made of silver - which is an ideal metal for plasmonics - opens intriguing perspectives for combining electronic and plasmonic switching in one and the same device at the atomic level. In this paper, we will demonstrate that photonic scaling is only limited by the atom. In particular we will present a novel plasmonic switch and photodetector featuring digital response at atomic scale. The principle of operation is based on the light-atom interaction in a memristive filament [5].

Wired and wireless high-speed communications enabled by plasmonics

Speed, footprint, power consumption and economiy of costs are key factors in the field of communications. The new field of plasmonics promises THz bandwidth devices with a micrometer footprint operating with fJ/bit at prices that scale similar to what is known from the CMOS industry. In this paper we will review recent advances in the field of plasmonics. An emphasis will be on the plasmonic organic hybrid platform with which we recently demonstrated the first 108 Gbit/s modulator, introduced a novel ultra-dense plasmonic interconnect solution or demonstrated a new radio-over-fiber scheme.