Gated Photon Transistor

research highlights

NANOPHOTONICS the control laser addressing the |d〉 → |s〉 numerical simulation results, demonstrating Black metals transition produced electromagnetically the important resonant behaviour of Appl. Phys. Lett. 102, 251105 (2013) induced transparency for gate photons structured graphene and hybridized systems. addressing the |g〉 → |d〉 transition. By They believe that this approach could reducing the control laser power to zero, a be extended to more complex systems, weak gate photon pulse could be stored in making it promising for investigating the atomic ensemble. This pulse could later and designing graphene-based THz and be retrieved by adiabatically reapplying the optoelectronic devices. SP control beam. When the average number of stored gate photons reached 2.9, the QUANTUM OPTICS transmission of the source light addressing Single-photon detectors the |s〉 → |e〉 transition was reduced by a Appl. Phys. Express 6, 072801 (2013) factor of five. The available gain outside the cavity was 1.4, demonstrating a gain Superconducting single-photon detectors

© 2013 AIP exceeding unity for transistor operation. NH (SSPDs) are widely used as high-performance devices in many fields, including quantum Mihail Bora and colleagues at Lawrence PLASMONICS information and quantum optics. The figure Livermore National Laboratory, USA, have Graphene metamaterials of merit of SSPDs is defined in terms of the investigated a metallic structure that absorbs Appl. Phys. Lett. 102, 253110 (2013) dark count rate (DCR) as η/(DCR × Δt), more than 95% of incident light. Their work where η is the detection efficiency and Δt builds on other recent research that typically Graphene-based metamaterials are is the timing jitter. The DCR is important uses metallic grooves or ‘funnels’ to minimize promising for developing new approaches because it governs the quantum bit error rate the impedance mismatch or reflection with to efficiently control terahertz (THz) in quantum key distribution experiments. the surroundings with the aim of trapping and infrared radiation. Two Japanese Now, Hiroyuki Shibata and colleagues from or nanofocusing light in the sample. Using researchers, Atsushi Ishikawa (RIKEN) and NTT Basic Research Laboratories, Japan, a square array of metal-coated nanowires, Takuo Tanaka (Hokkaido University), have have demonstrated an SSPD composed of the team showed that absorbance of the now experimentally and computationally NbN that has an ultralow DCR of less than substrates can be increased above 75% in investigated the THz plasmonic responses 1 cps. They found that the background the 400–800 nm range. The use of structures of structured graphene. Specifically, they signal at room temperature was produced fabricated from wires with more pronounced analysed plasmon hybridization in a by blackbody radiation propagating through matchstick-like tops formed more pronounced silicon oxide layer sandwiched between the optical fibre to the SSPD. To reduce the funnels, resulting in absorbances of over 90%. two graphene ribbons. The researchers DCR, they connected a coarse wavelength- Nanowire arrays were patterned on 4-inch produced this system by fabricating a division-multiplexer filter and a 1.6 μm wafers by laser interference lithography and single graphene ribbon on a thermally rejection short-wavelength-pass filter in were transferred to a silicon substrate by oxidized silicon oxide layer formed on a series to the SSPD and cooled the device directional deep reactive ion etching. The heavily doped p-type silicon substrate. The to 0.38 K. On inserting the filters, at a bias wire length and profile are determined by high reflectivity of the silicon substrate current of 22 μA, the DCR of the system the etch time. Such structures that employ effectively generated a mirror image of decreased from 14 cps to 0.1 cps, and the nanofocusing and dissipation to absorb light the structure. This configuration greatly system detection efficiency decreased have been dubbed ‘black metals’. DP simplifies the experimental study of the from 8.1% to 5.6%. As a consequence, the plasmonic responses of complex hybridized figure of merit increased by a factor of 97. QUANTUM OPTICS systems. The researchers found qualitative Numerical calculations indicate that if the Gated photon transistor agreement between experimental and SSPD system is connected to a standard Science http://dx.doi.org/10.1126/ science.1238169 (2013) ANGULAR MOMENTUM OF LIGHT Photons are excellent carriers of quantum Photonic wheel J. Europ. Opt. Soc. Rapid Pub. 8, 13032 (2013) information, but it is difficult to induce the strong interactions between individual Researchers at the University of Erlangen-Nuremberg, Germany have produced a novel photons required for all-optical quantum light beam that possesses angular momentum whose axis is orthogonal to the direction of information processing. Therefore, the propagation. The optical state, which the researchers call a ‘photonic wheel’, is analogous realization of an optical transistor exhibiting to a bicycle wheel in motion along a path. The two types of angular momentum of light — gain with gate signals at the few-photon level spin momentum resulting from the light’s polarization and orbital momentum produced remains a challenge. Now, Wenlan Chen and by a twisted phase front — are usually longitudinal as their axes are parallel to the beam’s co-workers from USA, Austria and Japan motion. Peter Banzer and co-workers realize the ‘photonic-wheel’ state by converting a have realized an optical transistor that is linearly polarized beam into two lateral components with opposing spin (one is left circularly gated by a single stored photon. The system polarized, whereas the other is right circularly polarized) using a special optical element consists of an ensemble of laser-cooled 133Cs consisting of two quarter waveplates. The beam is tightly focused using a microscope atoms optically trapped in a high-finesse objective. Its electric field is then analysed by measuring the light scattered from a gold optical cavity. Each atom has a four-state nanoparticle on a glass substrate that is scanned across the beam. The researchers propose N-type level structure with two stable ground that such a wheel state may find applications in various optical manipulation techniques, such states (|g〉 and |s〉) and two electronic excited as optical tweezers and spanners. OG states (|d〉 and |e〉). The group found that