Fullerenes with μSR

The current status ofSR results on muonium states in the pure fullerenes C₆₀ and C₇₀ is summarized. The hyperfine interaction between the unpaired electron and the muon provides unique information on the molecular dynamics and local electronic structure of the fullerenes. Recent results on the alkali doped C₆₀ series are also presented.     

Ultrasound focusing with metamaterial

Ultrasonic waves,although not audible,naturally exist at high frequencies.Ultrasound can be controlled and unitized in various scenarios.Well-known examples are bats and dolphins,which produce ultrasound and detect the reflected signal for navigating and hunting.     

γγ interactions with KLOE

Studies of γγ interactions are performed with the KLOE detector, without tagging of the outgoing e^＋e^-. The data sample is from an integrated luminosity of 240 pb^-1. It was collected at the φ-factory DAONE with e^＋e^- beams colliding at √s ≌1 GeV, below the φ resonance peak. We present preliminary results concerning the observation of the γγ→η process and the evidence for γγ→π^0π^0 production at low π^0π^0 invariant masses.     

γγ interactions with KLOE

Studies of γγ interactions are performed with the KLOE detector,without tagging of the outgoing e+e-.The data sample is from an integrated luminosity of 240 pb-1.It was collected at the φ-factory DAΦNE with e+e-beams colliding at s～(1/2) 1 GeV,below the φ resonance peak.We present preliminary results concerning the observation of the γγ→η process and the evidence for γγ→π0π0 production at low π0π0 invariant masses.     

Superadditivity with Mixed States Ensemble

Superadditivity is a special property in quantum communication theory. We present the optimal measurement for a mixed-state ensemble and calculate the amount of one-shot capacity, which is connected to the intensity of noise of the channel. Then the property of superadditivity is preserved when the mixed-state ensemble is used to transmit information.     

Quantum counterfactuality with identical particles

Quantum self-interference enables the counterfactual transmission of information, whereby the transmitted bits involve no particles traveling through the channel. In this work, we show how counterfactuality can be realized even when the self-interference is replaced by interference between identical particles. Interestingly, the facet of indistinguishability called forth here is associated with first-order coherence, and is different from the usual notion of indistinguishability associated with ...     

Quantum Cryptography with Entangled QuNits

We propose an extension of quantum key distribution based on encoding the key into quiNits, i.e. quantum statesin an iv-dimensional Hilbert space. In our protocol, we adopt asymmetric measurement scheme resulting in an efficiency higher than previous protocols and a generalized Bell inequality [Phys. Rev. Lett. 92 (2004) 130404] is employed to detect the presence of an eavesdropper Eve. We also derive the information gained by a potential eavesdropper Eve applying a cloning-based attack and the maximal error rate which measures the robustness of the protocol. The result shows that the security of our scheme increases with the dimension N.     

Adaptive synchronization with nonlinear input

This paper considers the adaptive synchronization problem of the drive—response type chaotic systems. Using a transmitted scalar signal with an unknown time-delay, a response system is constructed. By appropriately selecting the observer gain and designing the controller, synchronization can be achieved in the presence of the drive system's disturbances and unknown parameters. A well-known chaotic system, Chua's circuit, is considered as an illustrative example to demonstrate the effectiveness of the proposed approach.     

Faithful Telecloning with Multiparticle Entanglement

We study the 1→N faithful telecloning of two linear-independent states of a one-qubit system.Based on the analysis of the probabilistic cloning machine,we construct a multiparticle entangled state,and present a telecloning scheme under local operations and classical communication (LOCC).The success probability is greater than half of the optimal probability of the probabilistic cloning machine.Specifically,we show how to prepare the three-particle entangled state meeded by 1→2 telecloning under LOCC using the Greenberger-Horne-Zeilinger state as a resource.All the operations in 1→2 telecloning are within the reach of current technology.     

Sub-30 nm lithography with near-field scanning optical microscope combined with femtosecond laser

We report direct laser writing of lithography patterns with a feature width of 20±5 nm on thin photoresist film by combining a double-frequency femtosecond laser and a near-field scanning optical microscope. The obtained feature size is much smaller than the laser wavelength () and the aperture diameter (d) with a resolution of /20 and d/2, respectively. The lithography patterns were analyzed with an atomic force microscope and a scanning electron microscope. The effects of laser energy and writing speed on the feature size were investigated. The underlying physical mechanism was also discussed. PACS 07.79.Fc; 07.79.Lh; 42.70.Jk; 68.37.Hk; 81.16.Nd     

Spread spectrum-based ultraviolet communication with experiments

We report experiments of ultraviolet （UV） communication based on spread-spectrum technique. Field measurements via online UV communication are conducted to compare the system performances with and without spectrum spreading. The results indicate that the spread-spectrum technique is capable of suppressing noise in UV atmospheric scattering channel and therefore improve the system performance evidently. Details of implementation are also provided to make the results useful for similar system design in research on optical wireless communications.     

Čerenkov Effect with Massive Photons

The equations of massive electrodynamics are derived and the power spectrum formula for the erenkov radiation of massive photons is found. It is argued that the massive erenkov effect can be observed in superconductive media, ionosphere plasma, waveguides, and in particle laboratories.     

Model with strong γ4 T-violation

We extend the T violating model of the paper on ``Hidden symmetry of the CKM and neutrino-mapping matrices" by assuming its T-violating phases χ_↑ and χ_↓ to be large and the same, with χ=χ_↑=χ_↓. In this case, the model has 9     

Optical Automatic Focusing with Interference Fringes

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SOI thermo-optic modulator with fast response

Silicon-on-insulator (SOI) technology offers tremendous potential for integration of optoelectronic functions on a silicon wafer. In this letter, a 1 x 1 multimode interference (MMI) Mach-Zender interferometer (MZI) thermo-optic modulator fabricated by wet-etching method is demonstrated. The modulator has an extinction ratio of -11.0 dB, extra loss of -4.9 dB and power consumption of 420 mW. The response time is less than 30μs.     

Video stabilization with sub-image phase correlation

A fast video stabilization method is presented, which consists of sub-image phase correlation based global motion estimation, Kalman filtering based motion smoothing and motion modification based compensation. Global motion is decided using phase correlation in four sub-images. Then, the motion vectors are accumulated to be Kalman filtered for smoothing. The ordinal motion compensation is applied to each frame with modification to prevent error propagation. Experimental results show that this stabilization system can remove unwanted translational jitter of video sequences and follow intentional scan at real-time speed.     

Oxide-apertured VCSEL with short period superlattice

Novel distributed Bragg reflectors (DBRs) with 4.5 pairs of GaAs/AlAs short period superlattice (SPS) used in oxide-apertured vertical-cavity surface-emitting lasers (VCSELs) were designed. The structure of a 22-period Al0.9Ga0.1 As (69.5 nm)/4.5-pair [GaAs (10 nm)-AlAs (1.9 nm)] DBR was grown on an n+ GaAs substrate (100) 2° off toward <111>A by molecular beam epitaxy. The emitting wavelength was 850 nm with low threshold current of about 2 mA, corresponding to the threshold current density of 2 kA/cm2. The maximum output power was more than 1 mW. The VCSEL device temperature was increased by heating ambient temperature from 20 to 100℃ and the threshold current increased slowly with the increase of temperature.