Abstract-0.25 mW Pulsed Terahertz Radiation from Bias-Free, Telecommunication-Compatible Plasmonic Nanoantennas

Deniz Turan,  Nezih Tolga Yardimci. Mona Jarrahi

https://ieeexplore.ieee.org/document/8750171

We present a bias-free, telecommunication-compatible photoconductive terahertz source, which offers radiation powers exceeding 0.25 mW, enabling time-domain terahertz spectroscopy with more than a 90 dB dynamic range over a 0.1-3.5 THz bandwidth
. © 2019 The Author(s)

http://www.formation-continue-unil-epfl.ch/thz

TeraHertz: New opportunities for industry

Special Focus Session: THz Materials Measurements

3-5 February 2015

Target audience

R&D managers, engineers and scientists seeking a comprehensive update on TeraHertz technologies and applications, a disruptively evolving field.
A general background in science & technology is sufficient.

Overview

TeraHertz (THz), the frequencies between electronics and optics,
was until recently the last unexploited part of the electro-
magnetic spectrum. The harnessing of THz-based technologies has the potential of impacting globally a vast number of industries, like both electronics in the 70’s and optics in the 80’s did.
THz applications span over a wide array of fields, including:

• Quality Control and Non-destructive testing
• Surface analysis
• Security
• Chemical and Bio-Medical analysis
• Telecommunications

Filling the TeraHertz “gap” has led to unprecedented creativity in the development and commercialization of TeraHertz sources, transmission components and detectors.
This year’s edition will focus on THz materials measurements and applications.

Objectives

• Learn about the latest developments around material measurements towards TeraHertz
• Discover new application opportunities for THz material
 measurements
• Network with specialists in this emerging field

Topics and Hands-on

• THz test & measurements instrumentations: 
Network Analyzers
• THz solid state sources
• THz on-chip measurements and material measurements fixtures
• THz photonic measurements
• Application opportunities of THz material measurements

Keynote speakers from industry will give an overview of 
material measurements and challenges. The course also includes targeted exhibit with demonstrators.
Click here for more information on the event program, as well as on 
previous editions of this course.

Certification

A certificate of participation will be delivered at the end of the course.

Organization

• Nanostructured Materials Physics Laboratory (LPMN), Institute of Condensed Matter Physics (ICMP), School of Basic Sciences (FSB), Ecole Polytechnique Fédérale de Lausanne (EPFL)

In collaboration with

• SWISSto12 SA, a company issued from the EPFL Science Park

Steering committee

• Prof. Jean-Philippe Ansermet, School of Basic Sciences, ICMP, EPFL
• Dr. Alessandro Macor, SWISSto12 SA
• Dr. Emile de Rijk, SWISSto12 SA

Confirmed Speakers from

• Giovanni d’Amore, Keysight Technologies
• Glenn Oliver,
 Du Pont Electronics & Communications
• Philip Taday, Teraview
• Jeffrey Hesler, 
Virginia Diodes
• Fabian Friederich, 
Fraunhofer IPM
• Ferenc Murányi,
 Speag
• Andreas Henkel, 
Rohde & Schwarz
• Alvaro Diaz-Bolado,
 AstraZeneca
• David Daughton,
 Lake Shore Cryotronics
• Luis Rolo,
 European Space Agency
• Claire Watts,
 Boston College
• Dook van Mechelen,
 ABB
• Vessen Vassilev,
 Chalmers
• Emile de Rijk,
 SWISSto12

Dates and schedule

• Tuesday, 3 February 2015, 1.30 pm to 6 pm
• Wednesday, 4 February 2015, 9 am to 6 pm
• Thursday, 5 February 2015, 
9 am to 1 pm

Course venue

EPFL, Lausanne, Switzerland

Registration

800.- Swiss Francs (includes course material and refreshments)
Limited places available.
Registration deadline: 23 January 2015

- See more at: http://www.formation-continue-unil-epfl.ch/thz#sthash.87N5prmt.f5Qp6eQh.dpuf

OT- Raman scattering key to next-gen laser optical comms

http://global.ofweek.com/news/Raman-scattering-key-to-next-gen-laser-optical-comms-13900

The improvements in the performance of powerful lasers, optical fibres and peripheral technology have provided a sizable contribution to the proliferation of global telecommunications based on the transmission of 10GHz pulses of light. Particularly, the three most important properties of lasers for telecommunications are high power, single frequency and ultra-short pulse width.

Innovations pertaining to this technology can be found in the research being conducted by Professor Masayuki Katsuragawa, at the department of applied physics and chemistry, UEC.

"My research is focused on the manipulation of light-matter interaction for producing ultra-short pulses of laser light," stated Katsuragawa. "Our recent experiments on adiabatic stimulated Raman scattering in parahydrogen show potential for the realisation of laser light sources producing pulses at terahertz repetition-rate frequencies. These ultra-short pulses offer a new 'axis' in the evolution of laser based optical science."

Here, the 'axis' refers to ultrahigh-repetition-rate trains of monocycle pulses with precise control of the phase of the laser light pulses. Recently, Katsuragawa and his colleagues have reported on the realisation of ultrashort pulse trains of 1.8fs in duration and repetition frequency of 125THz by stimulated Raman scattering (SRSs) produced in parahydrogen. "The critical point in these experiments was driving Raman coherence adiabatically, that is, without dissipation," said Katsuragawa. "We achieved this by developing an injection-locked laser capable of emitting arbitrary pairs of two frequencies to irradiate the hydrogen gas, in order to control two photon detuning from the Raman resonance."

Recently, the UEC team has produced higher order series of stimulated Raman scattering using two driving lasers by the introduction of a second harmonic in one of the lasers. The resulting emission referred to as a 'Raman comb,' covered an octave spectrum range from the infrared to the ultraviolet.

"I am confident that our research has laid the foundations for the development of practical systems for the generation of trains of monocycle pulses with total control of the phase," noted Katsuragawa.

"Raman comb" generated by modulating single-frequency laser radiation with coherent molecular oscillations.

German researchers claim world record in silicon integrated nanophotonics

Paul Buckley
http://www.electronics-eetimes.com/en/german-researchers-claim-world-record-in-silicon-integrated-nanophotonics.html?cmp_id=7&news_id=222917486&vID=209


Researchers of the Institute of Electrical and Optical Communications Engineering (INT) at the and the Institut für Mikroelektronik Stuttgart (IMS CHIPS) are claiming a new world record in the energy efficient integration in silicon.

The achievement is an important step to decrease the energy consumption of data transfer in internet and telecommunication. The researchers optimized aperiodic grating couplers in the nanometer range with a new developed backside metal mirror. Through this new method a record coupling efficiency of 87 percent between optical fibers and photonic integrated waveguides on silicon wafers has been achieved.

The internet and telecommunications are based on an optical core network that connects cities worldwide using glass fibers. These can carry light with low losses over long distances. Based on a study published by CISCO, the mobile data transfer (smartphones) will solely increase from 885 petabytes per month (end of 2012) up to ten exabytes per month in the year 2017.

Researchers of the INT and IMS CHIPS have developed a fabrication process to realize complex sender and receiver structures that are integrated on silicon wafers. Existing optical senders and receivers are based on indium phosphide substrates, which are available only in small dimensions and to high costs. Experts predict that optical connections will be necessary in the home computer of the year 2020 to exchange the huge amount of data between individual components of the computer. The used light has a frequency of around 192 Terahertz and can offer bandwidths of several Terahertz and data rates beyond 1 Terabit/s. Worldwide researchers are trying to develop new components to make use of these tremendous data rates in commercial products. Because silicon is transparent at the used light frequency, this material can be utilized in waveguiding structures. Computing based on photons in nanoelectronic circuits can be then achieved in future computer components.

For this purpose light has to be efficiently guided in silicon waveguides and coupled from one component to another. The resulting energy losses have to be kept as small as possible. Researchers of the University of Stuttgart achieved the new world record in coupling efficiency between optical fibers and integrated silicon waveguides based on the new developed aperiodic grating coupler structures that are fabricated using the technology process of IMS CHIPS. With a record of 87 percent and a bandwidth of around 40 nm the new structures can pave the way for more efficient integration of optical senders and receivers in silicon.

In this complementary-metal-oxide-semiconductor fabrication process other components such as polarization beam splitters based on grating structures are also realized.

The results of the research will be published in September at the European Conference on Optical Communications in London (http://www.ecoc2013.org/).

Controlling Gigahertz and Terahertz Surface Electromagnetic Waves with Metamaterial Resonators

http://prx.aps.org/abstract/PRX/v1/i2/e021016

Popular Summary: In the rapidly advancing arena of modern telecommunication technology, new concepts or paradigms are being sought for guided and lossless transmission of surface electromagnetic waves at the terahertz and higher frequencies. In this paper of combined theoretical and experimental work, we put forward just such a concept that marries the classical idea of surface electromagnetic waves with some very recent advances in metamaterials research.

Surface electromagnetic waves, first predicted by Arnold Sommerfeld in 1899 in the form of an axial cylindrical wave, are low-frequency electromagnetic waves that are bound to a metallic interface between two different media and travel without radiation loss. They can serve as guided waves that are of vital importance in routing electromagnetic energy from a source to a device or receiver and become especially competitive for integrated telecommunication devices in the frequency range of terahertz. Metamaterials, emerged only recently, are a broad class of materials constructed of individual elements in a bottom-up approach, with the designed-on-demand capability of manipulating or modulating electromagnetic waves propagating in free space. Our concept combines a planar gigahertz or terahertz version of the Goubau transmission line—well known in the radio-frequency transmission technology—with a few coupled metamaterial elements (electric-ring resonators) judiciously placed next to the Goubau line. We have demonstrated that the metamaterial elements can be designed to either absorb or transmit the surface-wave energy in the Goubau line and yield narrow-band resonances with relatively high quality factors. By tuning the coupling between the metamaterial elements, we have also succeeded in achieving a large dynamic range of transmissivity.

Our proof-of-concept demonstration should trigger new developments in ultrahigh-speed data transmission and processing and lead to a place for metamaterials in future high-bandwidth terahertz communications.