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NEW YORK, USA: Prof. Gertrude Neumark Rothschild has reached a settlement with Mitsubishi Corp. regarding her assertion that the company and dozens of other major electronics manufacturers in Asia and Europe violated her patents for producing light emitting diodes and laser diodes in products, such as video players that are used for Sony’s Blu-ray format, Motorola Razr phones and Hitachi camcorders, backlighting for computers, as well as street lighting and optical storage of information.

Mitsubishi is the latest company to reach a global settlement with Rothschild, a professor emeritus at Columbia University. Others who have settled include BenQ, Dalien Lumei, Epistar Corp., FOREPI, Guangzhou Hongli, Hitachi, Hugo Optotech, LG, Motorola, Pioneer Corp., Samsung Electro Mechanics, Samsung Electronics, Sanyo Electric, Sewa Electric, Sharp Corp., Shenzhen Unilight, Showa Denko, Sony Corp., and Sony Ericcson. Earlier settlements were made with Nichia Chemical and Koninklijke Philips Electronics, which included Philips Lumilid Lighting Co. and Toyoda Gosei Co. Ltd.

Terms of the Mitsubishi agreement are confidential, according to Rothschild’s attorney, Albert Jacobs Jr. of Troutman Sanders LLP. However, the aggregate received from her settlements and licenses — which now have been concluded with more than 40 companies — amounts to over $27 million, Jacobs said.

“Dr. Rothschild made a seminal breakthrough in the production of LEDs and LDs, especially the blue, violet and ultraviolet LEDs that are essential to a wide variety of consumer electronics products today,” said Jacobs. “She richly deserves both scientific as well as commercial recognition for her work.”

Prof. Rothschild, who is the sole owner of US Patent Number 5,252,499, as well as the recently expired ‘618 patent and foreign patents related thereto, is currently Howe Professor Emeritus of Materials Science and Engineering at Columbia.

She conducted ground-breaking research in the 1980s and 1990s into the electrical and optical properties of so-called wide band-gap semiconductors. This research has proven pivotal in the development of short-wavelength emitting (blue and violet) diodes that are now widely used in consumer electronics.

She was issued two US patents in the early 1990s that cover methods of producing wide band-gap semiconductors for LEDs and LDs. Such LEDs and LDs have become increasingly popular in a variety of devices as a superior lighting source because of their reduced power consumption, greater reliability, longevity and greater storage capacity.

Recognized by the American Physical Society as a Notable Woman Physicist in 1998, Professor Rothschild was elected as a Fellow of the American Physical Society in 1982.

Prof. Rothschild began her research career in private industry, working with Sylvania Research Laboratories in Bayside, N.Y., in the 1950s, and later at Philips Laboratories in Briarcliff Manor, N.Y. She joined the faculty at Columbia University as a Professor of Materials Science in 1985. In 2008, she was selected as a recipient of Barnard College’s Distinguished Alumna Award. She has published approximately 90 research articles and given 28 invited talks since 1980.

Journal Science: Realization of an Excited, Strongly Correlated Quantum Gas Phase

Ultracold atomic physics offers myriad possibilities to study strongly correlated many-body systems in lower dimensions. Typically, only ground-state phases are accessible. Using a tunable quantum gas of bosonic cesium atoms, we realized and controlled in one-dimensional geometry a highly excited quantum phase that is stabilized in the presence of attractive interactions by maintaining and strengthening quantum correlations across a confinement-induced resonance. We diagnosed the crossover from repulsive to attractive interactions in terms of the stiffness and energy of the system. Our results open up the experimental study of metastable, excited, many-body phases with strong correlations and their dynamical properties.

Nanowerk has coverage

The researchers produced a quantum gas made up of bosonic caesium atoms in a vacuum chamber. Then, they generated an optical lattice using two laser beams; the lattice confined the atoms to vertical, one-dimensional structures with up to 15 atoms aligned in each ‘tube’. The laser beams prevented the atoms from shifting out of line or changing places. Once this was achieved, the scientists used a magnetic field to tune the interaction among the atoms.

‘By increasing the interaction energy between the atoms (attraction interaction), the atoms start coming together and the structure quickly decays,’ explained Dr Naegerl. This is called the ‘Bosenova effect’. When the interaction energy is minimised, the atoms are able to repel instead of attract each other; this allows them to align vertically and regularly along a one-dimensional structure. The resulting system is stable.

The researchers observed a surprising effect when the interactions were switched from strongly repulsive to strongly attractive. They achieved ‘an exotic, gas-like phase, where the atoms are excited and correlated but do not come together and the ‘Bosenova effect’ is absent’, said Dr Naegerl.

According to co-investigator Elmar Haller of the University of Innsbruck, the phase was predicted four years ago. ‘We have now been able to realise it experimentally for the first time,’ he stated.

The experimental setup will be used in future studies to investigate the properties of quantum wires, which have until now been extremely difficult to observe. Further research on low-dimensional structures may also shed light on the functioning of high-temperature superconductors.

4 pages of supplemental material

Lattice loading.
We produce a BEC of Cs atoms in the lowest hyperfine sublevel with hyperfine quantum
numbers F = 3 and mF = 3 in a crossed beam dipole trap with trap frequencies !x;y;z =
2 (15; 20; 13) Hz, where z denotes the vertical direction. The BEC is adiabatically transferred from the dipole trap to the array of tubes by exponentially ramping up the power in the lattice laser beams with waists 350 m within 500 ms. The repulsive interaction causes the atoms to move radially outwards during the initial phase of the lattice loading in response to the strong local compression. We use this effect to vary the total number of tubes loaded and hence the atom number per tube by setting a3D for the loading process to values between 40 a0 and 350 a0. For the data set in the repulsive regime (Fig.3A, circles), we exponentially ramp down the crossed beam dipole trap during the loading process and reach longitudinal and transversal trap frequencies of !D = 2 15:4(1) Hz and !? = 2 13:1(1) kHz with a transversal confinement length a? = 1440(6) a0. Here, depending on the regime of interaction to be studied, the number of atoms in the central tube is set to values between 8 and 25. For the data set in the sTG regime (Fig.3A, squares) we increase !D to 2 115:6(3) Hz to reduce the vertical extent of the sample and hence the variation of the magnetic field across the atom cloud. For this, we keep the depth of the crossed beam dipole trap constant during the loading process and then ramp up the power in one of the beams within 100 ms. The number of atoms in the central tube is set to values between 8 and 11.

Array of 1D tubes….

1. New Scientist reports that the codebreaking quantum computer algorithm (shors algorithm for factoring) has been run on a silicon chip.

Journal Science abstract: Shor’s Quantum Factoring Algorithm on a Photonic Chip

Shor’s quantum factoring algorithm finds the prime factors of a large number exponentially faster than any other known method, a task that lies at the heart of modern information security, particularly on the Internet. This algorithm requires a quantum computer, a device that harnesses the massive parellism afforded by quantum superposition and entanglement of quantum bits (or qubits). We report the demonstration of a compiled version of Shor’s algorithm on an integrated waveguide silica-on-silicon chip that guides four single-photon qubits through the computation to factor 15.

BBC News reports: The Bristol team’s approach makes use of waveguides – channels etched into the chips that provide a path for the photons around the chips like the minuscule wires in conventional electronics.

The work, reported in Science, is rudimentary but could easily be scaled up to handle more complex computing.

While Professor O’Brien said he is confident that such waveguides are the logical choice for future optical quantum computers, he added that there is still a significant amount of work to do before they make it out of the laboratory.

“To get a useful computer it needs to be probably a million times more complex, so a full-scale useful factoring machine is still at least two decades away,” he said.

“But this is one important step in that direction.”

The device performs a compiled version of the quantum routine in Shor’s algorithm.

A study demonstrates that complex quantum circuits can be built relatively easily out of silicon and silica – a significant milestone on the road to full-blown quantum computing.

Fifteen years ago, Peter Shor, a computer scientist at the Massachusetts Institute of Technology, predicted that quantum computers could beat even the most powerful supercomputers and crack the widely used RSA encryption algorithm.

The 26-millimetre-long chip was designed and built using standard fabrication processes by Jeremy O’Brien, Jonathan Matthews and Alberto Politi at the University of Bristol, UK. It can run Shor’s algorithm in cut-down form – confirming that 3 and 5 multiply to form 15, which is the simplest possible demonstration.

Unlike the silicon chips inside conventional computers, the Bristol team’s chip uses light rather than electricity. Light-transmitting silica on a silicon wafer guides photons with entangled quantum properties around, an approach first demonstrated by the same team last year.

White points out that the technology used to generate individual photons to feed into the chip, and to detect them as they emerge, is not efficient, fast or compact enough yet. Although the new chip is only 26 mm long, it has to be surrounded by a whole table top of that equipment.

2 pages of supplemental information on photonic quantum computing.

2. Abstract from Journal Science: Complete Methods Set for Scalable Ion Trap Quantum Information Processing

Large-scale quantum information processors must be able to transport and maintain quantum information and repeatedly perform logical operations. Here, we show a combination of all of the fundamental elements required to perform scalable quantum computing through the use of qubits stored in the internal states of trapped atomic ions. We quantified the repeatability of a multiple-qubit operation and observed no loss of performance despite qubit transport over macroscopic distances. Key to these results is the use of different pairs of 9Be+ hyperfine states for robust qubit storage, readout, and gates, and simultaneous trapping of 24Mg+ “re-cooling” ions along with the qubit ions.

The Supporting Online Materials provide further details about the sympathetic cooling, the use of state-dependent forces to implement a geometric phase gate using multiple motional modes, transfer between the gate and memory qubit manifolds, state detection and error analysis for quantum process tomography. [4 pages of Supplemental information]

Polarisation of laser emission from a plasmonic and
photonic lasers: the arrows indicate the direction of the |E| field. The |E| field of the plasmon laser mode is predominantly polarised along the nanowire axis and scatters most effectively to radiation with a similar polarisation

Plasmon lasers at deep subwavelength scale

Laser science has been successful in producing increasingly high-powered, faster and smaller coherent light sources. Examples of recent advances are microscopic lasers that can reach the diffraction limit, based on photonic crystals, metal-clad cavities and nanowires. However, such lasers are restricted, both in optical mode size and physical device dimension, to being larger than half the wavelength of the optical field, and it remains a key fundamental challenge to realize ultracompact lasers that can directly generate coherent optical fields at the nanometre scale, far beyond the diffraction limit. A way of addressing this issue is to make use of surface plasmons which are capable of tightly localizing light, but so far ohmic losses at optical frequencies have inhibited the realization of truly nanometre-scale lasers based on such approaches. A recent theoretical work predicted that such losses could be significantly reduced while maintaining ultrasmall modes in a hybrid plasmonic waveguide. Here we report the experimental demonstration of nanometre-scale plasmonic lasers, generating optical modes a hundred times smaller than the diffraction limit. We realize such lasers using a hybrid plasmonic waveguide consisting of a high-gain cadmium sulphide semiconductor nanowire, separated from a silver surface by a 5-nm-thick insulating gap. Direct measurements of the emission lifetime reveal a broad-band enhancement of the nanowire’s exciton spontaneous emission rate by up to six times owing to the strong mode confinement and the signature of apparently threshold-less lasing. Because plasmonic modes have no cutoff, we are able to demonstrate downscaling of the lateral dimensions of both the device and the optical mode. Plasmonic lasers thus offer the possibility of exploring extreme interactions between light and matter, opening up new avenues in the fields of active photonic circuits, bio-sensing and quantum information technology

29 page pdf with supplemental information on Plasmon lasers at deep subwavelength scale

PALO ALTO, USA: GigOptix Inc. today announced the use of its 100G LX8900 Mach-Zehnder Modulator (MZM) by Photon-X, LLC, a manufacturer of advanced fiber optic and RF photonic devices and subsystems.

The LX8900 with an optical bandwidth of 65GHz enables customers to modulate a signal’s phase and amplitude at ultra high frequencies in the optical domain.

Existing modulation mechanisms operating at these frequencies suffer from a number of drawbacks including narrow bandwidth and high power dissipation. Moreover, other optical modulator technologies such as Lithium Niobate and Indium Phosphide are not able to perform at these high speeds.

The LX8900, due to the intrinsic properties of the GigOptix’s EO polymer material, is not only able to operate at ultra high frequencies but also provide a broadband response in a small, low power, radiation hard form factor.

The LX8900 and its future derivatives are expected to have applicability in defense and aerospace and be used in phase array radar, antenna remoting, RF beam steering and ultra high frequency signal mixing applications.

“This collaboration with Photon-X is a great opportunity to leverage our technology beyond the high speed optical communications arena into new markets such as wide band RF Photonics in defense and aerospace systems,” said Andrea Betti-Berutto, Chief Technical Officer of GigOptix.

“The LX8900 is a unique product in terms of its high speed and broadband operation and it is a great addition to our expanding RF solution portfolio of broadband amplifier devices.”

“GigOptix electro-optic polymer technology provides a very exciting opportunity for us to develop new innovative high speed and wide band products in the RF photonics space,” said Renfeng Gao, Director of Photon-X, LLC. “The LX8900’s bandwidth and performance characteristics are very impressive and we believe will open up a whole new realm of RF photonic applications.”

Samples are available immediately.