Viet Giang Truong - Okinawa Institute of Science and Technology Graduate University, Onna-son, Japan

Viet Giang Truong
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Name
Viet Giang Truong
Affiliation
Okinawa Institute of Science and Technology Graduate University, Onna-son, Japan
City
Onna
Country
Japan

Pubs By Year

Pub Categories

 
Physics - Optics (9)
 
Physics - Atomic Physics (2)
 
Physics - Mesoscopic Systems and Quantum Hall Effect (2)
 
Physics - Materials Science (2)
 
Physics - Instrumentation and Detectors (1)
 
Quantum Physics (1)

Publications Authored By Viet Giang Truong

We experimentally realized an optical nanofiber-based cavity by combining a 1-D photonic crystal and Bragg grating structures. The cavity morphology comprises a periodic, triplex air-cube introduced at the waist of the nanofiber. The cavity has been theoretically characterized using FDTD simulations to obtain the reflection and transmission spectra. Read More

We present a systematic treatment of higher-order modes of vacuum-clad ultrathin optical fibers. We show that, for a given fiber, the higher-order modes have larger penetration lengths, larger effective mode radii, and larger fractional powers outside the fiber than the fundamental mode. We calculate, both analytically and numerically, the Poynting vector, propagating power, energy, angular momentum, and helicity (or chirality) of the guided light. Read More

Particles trapped in the evanescent field of an ultrathin optical fibre inter-act over very long distances via multiple scattering of the fibre-guided fields. In ultrathin fibres that support higher order modes, these interac-tions are stronger and exhibit qualitatively new behaviour due to the cou-pling of different fibre modes, which have different propagation wave-vectors, by the particles. Here, we study one dimensional longitudinal opti-cal binding interactions of chains of 3 {\mu}m polystyrene spheres under the influence of the evanescent fields of a two-mode microfibre. Read More

While conventional optical trapping techniques can trap objects with submicron dimensions, the underlying limits imposed by the diffraction of light generally restrict their use to larger or higher refractive index particles. As the index and diameter decrease, the trapping difficulty rapidly increases; hence, the power requirements for stable trapping become so large as to quickly denature the trapped objects in such diffraction-limited systems. Here, we present an evanescent field based device capable of confining low index nanoscale particles using modest optical powers as low as 1. Read More

2015Jun
Affiliations: 1Okinawa Institute of Science and Technology Graduate University, Onna-son, Japan, 2Okinawa Institute of Science and Technology Graduate University, Onna-son, Japan, 3Okinawa Institute of Science and Technology Graduate University, Onna-son, Japan, 4Okinawa Institute of Science and Technology Graduate University, Onna-son, Japan

Precise control of particle positioning is desirable in many optical propulsion and sorting applications. Here, we develop an integrated platform for particle manipulation consisting of a combined optical nanofibre and optical tweezers system. Individual silica microspheres were introduced to the nanofibre at arbitrary points using the optical tweezers, thereby producing pronounced dips in the fibre transmission. Read More

2014Sep
Affiliations: 1Light-Matter Interactions Unit, OIST Graduate University, Onna-son, Okinawa, Japan, 2Light-Matter Interactions Unit, OIST Graduate University, Onna-son, Okinawa, Japan, 3Light-Matter Interactions Unit, OIST Graduate University, Onna-son, Okinawa, Japan, 4Light-Matter Interactions Unit, OIST Graduate University, Onna-son, Okinawa, Japan, 5Light-Matter Interactions Unit, OIST Graduate University, Onna-son, Okinawa, Japan

Optical manipulation in the vicinity of optical micro- and nanofibres has shown potential across several fields in recent years, including microparticle control, and cold atom probing and trapping. To date, most work has focussed on propagation of the fundamental mode through the fibre. However, along the maximum mode intensity axis, higher order modes have a longer evanescent field extension and larger field amplitude at the fibre waist compared to the fundamental mode, opening up new possibilities for optical manipulation and particle trapping. Read More

The evanescent field of an optical nanofiber presents a versatile interface for the manipulation of micron-scale particles in dispersion. Here, we present a detailed study of the optical binding interactions of a pair of 3.13 $\mu$m SiO$_2$ particles in the nanofiber evanescent field. Read More

Precise control of particle positioning is desirable in many optical propulsion and sorting applications. Here, we develop an integrated platform for particle manipulation consisting of a combined optical nanofiber and optical tweezers system. Individual silica microspheres were introduced to the nanofiber at arbitrary points using the optical tweezers, thereby producing pronounced dips in the fiber transmission. Read More

We propose an optical dipole trap for cold neutral atoms based on the electric field produced from the evanescent fields in a hollow rectangular slot cut through an optical nanofibre. In particular, we discuss the trap performance in relation to laser-cooled rubidium atoms and show that a far off-resonance, blue-detuned field combined with the attractive surface-atom interaction potential from the dielectric material forms a stable trapping configuration. With the addition of a red-detuned field, we demonstrate how three dimensional confinement of the atoms at a distance of 140 - 200 nm from the fibre surface within the slot can be accomplished. Read More

The use of tapered optical fibers, i.e., optical nanofibers, for spectroscopy and the detection of small numbers of particles, such as neutral atoms or molecules, has been gaining ground in recent years. Read More

Understanding the origin of hysteresis in the channel resistance from top gated graphene transistors is important for transistor applications. Capacitance - voltage measurements across the gate oxide on top gated bilayer graphene show hysteresis with a charging and discharging time constant of ~100 {\mu}s. However, the measured capacitance across the graphene channel does not show any hysteresis, but shows an abrupt jump at a high channel voltage due to the emergence of an order, indicating that the origin of hysteresis between gate and source is due to charge traps present in the gate oxide and graphene interface. Read More

The electromagnetic enhancement for surface enhanced Raman spectroscopy (SERS) of graphene is studied by inserting a layer of Al2O3 between epitaxial graphene and Au nanoparticles. Different excitation lasers are utilized to study the relationship between laser wavelength and SERS. The theoretical calculation shows that the extinction spectrum of Au nanoparticles is modulated by the presence of graphene. Read More