114 research outputs found
Large energy soliton erbium-doped fiber laser with a graphene-polymer composite mode locker
Due to its unique electronic property and the Pauli Blocking Principle,
atomic layer graphene possesses wavelength-independent ultrafast saturable
absorption, which can be exploited for the ultrafast photonics application.
Through chemical functionalization, a graphene-polymer nanocomposite membrane
was fabricated and firstly used to mode lock a fiber laser. Stable mode locked
solitons with 3 nJ pulse energy, 700 fs pulse width at the 1590 nm wavelength
have been directly generated from the laser. We show that graphene-polymer
nanocomposites could be an attractive saturable absorber for high power fiber
laser mode locking.Comment: Large energy soliton erbium-doped fiber laser with a graphene-polymer
composite mode locker. Applied Physics Letters, Accepte
Graphene mode locked, wavelength-tunable, dissipative soliton fiber laser
Atomic layer graphene possesses wavelength-insensitive ultrafast saturable
absorption, which can be exploited as a full-band mode locker. Taking advantage
of the wide band saturable absorption of the graphene, we demonstrate
experimentally that wide range (1570 nm - 1600nm) continuous wavelength tunable
dissipative solitons could be formed in an erbium doped fiber laser mode locked
with few layer graphene
Long Range Intrinsic Ferromagnetism in Two Dimensional Materials and Dissipationless Future Technologies
The inherent susceptibility of low-dimensional materials to thermal
fluctuations has long been expected to poses a major challenge to achieving
intrinsic long-range ferromagnetic order in two-dimensional materials. The
recent explosion of interest in atomically thin materials and their assembly
into van der Waals heterostructures has renewed interest in two-dimensional
ferromagnetism, which is interesting from a fundamental scientific point of
view and also offers a missing ingredient necessary for the realization of
spintronic functionality in van der Waals heterostructures. Recently several
atomically thin materials have been shown to be robust ferromagnets. Such
ferromagnetism is thought to be enabled by magneto crystalline anisotropy which
suppresses thermal fluctuations. In this article, we review recent progress in
two-dimensional ferromagnetism in detail and predict new possible
two-dimensional ferromagnetic materials. We also discuss the prospects for
applications of atomically thin ferromagnets in novel dissipationless
electronics, spintronics, and other conventional magnetic technologies.
Particularly atomically thin ferromagnets are promising to realize time
reversal symmetry breaking in two-dimensional topological systems, providing a
platform for electronic devices based on the quantum anomalous Hall Effect
showing dissipationless transport. Our proposed directions will assist the
scientific community to explore novel two-dimensional ferromagnetic families
which can spawn new technologies and further improve the fundamental
understanding of this fascinating area.Comment: To be appear in Applied Physics Review
Large nonlinear Kerr effect in graphene
Under strong laser illumination, few-layer graphene exhibits both a
transmittance increase due to saturable absorption and a nonlinear phase shift.
Here, we unambiguously distinguish these two nonlinear optical effects and
identify both real and imaginary parts of the complex nonlinear refractive
index of graphene. We show that graphene possesses a giant nonlinear refractive
index n2=10-7cm2W-1, almost nine orders of magnitude larger than bulk
dielectrics. We find that the nonlinear refractive index decreases with
increasing excitation flux but slower than the absorption. This suggests that
graphene may be a very promising nonlinear medium, paving the way for
graphene-based nonlinear photonics.Comment: Optics Letters received 12/02/2011; accepted 03/12/2012; posted
03/21/2012,Doc. ID 15912
Vector Dissipative Solitons in Graphene Mode Locked Fiber Lasers
Vector soliton operation of erbium-doped fiber lasers mode locked with atomic
layer graphene was experimentally investigated. Either the polarization
rotation or polarization locked vector dissipative solitons were experimentally
obtained in a dispersion-managed cavity fiber laser with large net cavity
dispersion, while in the anomalous dispersion cavity fiber laser, the phase
locked NLSE solitons and induced NLSE soliton were experimentally observed. The
vector soliton operation of the fiber lasers unambiguously confirms the
polarization insensitive saturable absorption of the atomic layer graphene when
the light is incident perpendicular to its 2D atomic layer
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