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We propose and experimentally demonstrate a quantum-enhanced fiber Mach-Zehnder interferometer for low-frequency phase measurement beyond the shot-noise limit using a high-frequency squeezing technique. The local oscillator field is amplitude-modulated in the MHz range and is then demodulated to avoid the technical noise that occurs at low frequencies. After measurement of the phase noise at a frequency of tens of kHz, an improvement of ~2 dB relative to the shot-noise level is achieved. Additionally, the amplitude modulation depth has no significant effect on the phase noise improvement of the interferometer when deployed in our experimental configuration. The current scheme introduces a quantum technique into the fiber-based measurements, particularly for the low frequency range, and this scheme has potential applications in the high-precision fiber sensing of temperature, strain, and various other parameters. [ABSTRACT FROM AUTHOR]

We present Raman, terahertz transmission, and transport measurements on (Bi1-xInx)2Se3 films to study the evolution of phonon modes and resistivity with an increasing indium content across the metal-insulator phase transition. The frequencies of two Raman-active modes E2g and A21g as well as an infrared-active mode Eu increase with an increasing indium content due to the smaller atomic weight of indium compared to bismuth. Terahertz data are fitted by a Drude-Lorentz model. Drude scattering rates increase from 47 to 75cm-1 with an increasing indium content from 0% to 16% due to stronger impurity scattering. The carrier concentration drops significantly for x=24%. The temperature dependence of the resistivity switches from metallic at x=16% to insulating at x=24%, indicating a metal-insulator transition in between. [ABSTRACT FROM AUTHOR]

We propose a workable scheme for the generation of full spin polarization in ferromagnetic graphene system with strain or Rashba spin-orbit interaction. A spin energy gap can be opened in ferromagnetic graphene system in the presence of strain or Rashba spin-orbit interaction, leading to the full polarization in the spin energy gap. In addition, under the combined modulation of strain and Rashba spin-orbit interaction, the ferromagnetic graphene system can generate significantly large spin-polarized current with a full polarization in the spin energy gap. It is anticipated to apply such a phenomenon to design the electron spin devices based on the graphene. [ABSTRACT FROM AUTHOR]

The two-surface-plasmon-polariton-absorption (TSPPA) at the vacuum wavelength of 400 nm is observed, and the subwavelength lithography, by using this nonlinear phenomenon, is demonstrated. Resist patterns with the period of ~138nm have been obtained by exciting the SPP at the Al/resist interface with the 400 nm femtosecond laser. By altering the exposure time, the exposure linewidth reduces from ~90 nm to ~55 nm, which explores the ability of the TSPPA based lithography at the short wavelength. The factors limiting the performance of the proposed TSPPA based lithography are discussed in detail. [ABSTRACT FROM AUTHOR]

To connect the surface plasmon polariton (SPP) based devices with the conventional dielectric devices is a significant issue for the further development of SPP and related applications. In this paper, extremely high efficient coupling (>99%) between long range SPP (LRSPP) waveguide mode and TM mode of dielectric waveguide has been demonstrated from a hybrid coupler, which composed of an Au (LRSPP) waveguide and a SiN (dielectric) waveguide. Based on this hybrid coupler, a polarization splitter with pure TM mode output from one arm and TE mode output from the other arm with high TE/TM extinction ratio has been realized. [ABSTRACT FROM AUTHOR]

The nonlinear behaviors of the dielectric and piezoelectric responses of <001> oriented Pb(Zn[sub 1/3]Nb[sub 2/3])O[sub 3]-xPbTiO[sub 3] (PZN-PT) single crystals for x=4.5% and 8% have been investigated as a function of ac electric fields and dc bias fields. At relatively low applied fields, the polarization and strain of PZN-PT single crystals poled along the <001> direction show little hysteresis and have a linear dependence on the applied field, which is a consequence of engineered domain stability. Hence the dielectric and piezoelectric coefficients of the material do not exhibit any field dependence. However, when the applied electric field exceeds a threshold value, the strain and dielectric responses become nonlinear. The dielectric and piezoelectric constants are a function of the applied field, and hysteresis loops are observed. The results suggest that the observed nonlinear behavior in the PZN-PT single crystals is caused by domain motion/switching in response to the large ac fields. A positive dc bias effectively stabilizes the domain configuration in the crystals and enhances the linear response. The threshold field, at the onset of nonlinearity, is a linear function of the dc bias field in the field range investigated. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

We report a waveguiding excitation-based approach for surface-enhanced fluorescence. As high as 17-fold enhanced fluorescence intensity of Rhodamine 6G molecules is realized by gold nanoparticles embedded in polymer nanofibers. The enhancement results not only from the spatial confinement of light by the nanofibers but also from the wavelength match among the excitation laser, the localized surface plasmon resonance of nanoparticles, and the absorption band of dyes. On the basis of the enhancement and high-efficient waveguiding regime, the required excitation power for detectable fluorescence is decreased to the 20 nW level, which is about 50 times lower than that by free-space excitation. These fluorophore/nanoparticle-doped nanofibers may find applications in compact and energy-efficient optical devices of chemical analysis and biosensing. [ABSTRACT FROM AUTHOR]

Fabricating superhydrophobic surfaces via self-assembly of organic conjugated small molecules is realized by spray-drying the thiophene derivates organic solutions. Formation of microsized pores and arrayed nanofibers or nanorods on the surfaces is responsible for the superhydrophobicity of the coatings. This technique can be applied for fabrication of large area superhydrophobic surfaces with conjugated molecules on different substrates. [ABSTRACT FROM AUTHOR]

A single-layer polymer stabilized liquid crystal (PSLC) film reflecting both right- and left-circularly polarized light has been developed by a wash-out/refill method. The PSLC film was achieved by prefabricating the polymer network with a left-handed helical structure and then refilling a cholesteric liquid crystal with a right-handed helical structure into the network. The reflection intensity of the PSLC film is close to 100% when the pitch lengths of the two opposite helical structures are the same. It was demonstrated that the memory effect of the polymer network is an important mechanism for the resulting film properties. [ABSTRACT FROM AUTHOR]