Related papers: Characterization of the second- and third-order no…
Monolayer transition metal dichalcogenides (TMDs) exhibit high nonlinear optical (NLO) susceptibilities. Experiments on MoS$_2$ have indeed revealed very large second-order ($\chi^{(2)}$) and third-order ($\chi^{(3)}$) optical…
Efficient nonlinear wave mixing is of paramount importance for a wide range of applications. However, weak optical nonlinearities pose significant challenges for accessing nonlinear light-matter interaction in compact systems. Here, we…
We show that the lack of inversion symmetry in monolayer MoS2 allows strong optical second harmonic generation. Second harmonic of an 810-nm pulse is generated in a mechanically exfoliated monolayer, with a nonlinear susceptibility on the…
Since de discovery of graphene, the family of 2-dimensional materials has attracted much recent attention. In this work, the nonlinear optical properties of few-layer MoS2 two-dimensional crystals are studied using femtosecond laser pulses.…
Janus transition metal dichalcogenides are an emerging class of atomically thin materials with engineered broken mirror symmetry that gives rise to long-lived dipolar excitons, Rashba splitting, and topologically protected solitons. They…
We report observation of strong and anisotropic third harmonic generation (THG) in monolayer and multilayer ReS$_2$. The third-order nonlinear optical susceptibility of monolayer ReS$_2$, $\left| \chi^{(3)} \right|$ is on the order of…
Semiconducting Transition Metal Dichalcogenides (TMDs) have significant nonlinear optical effects. In this work we have used second-harmonic generation (SHG) and the four-wave mixing (FWM) spectroscopy in resonance with the excitons in…
3R-MoS2, a MoS2 polytype with broken inversion symmetry, enables unique light-matter interactions and is promising for linear and nonlinear integrated photonics beyond the monolayer limit. Yet, systematic studies of its thickness-dependent…
We report the first detailed characterization of the sheet third-harmonic optical susceptibility, $\chi_{s}^{(3)}$, of tungsten diselenide (WSe$_{2}$). With a home-built confocal microscope setup developed to study harmonics generation, we…
Nonlinear optical materials of atomic thickness--such as non-centrosymmetric 2H transition metal dichalcogenide monolayers--have a second order nonlinear susceptibility ($\chi^{(2)}$) whose intensity can be tuned by strain. However, whether…
We report ultra-strong high-order nonlinear multiphoton processes in monolayer MoS$_2$ (1L-MoS$_2$): the third harmonic is thirty times stronger than the second harmonic, and the fourth harmonic is comparable to the second harmonic. We find…
We calculate linear and nonlinear optical susceptibilities arising from the excitonic states of mono- layer MoS2 for in-plane light polarizations, using second-quantized bound and unbound exciton operators. Optical selection rules are…
The recent, rapid advances in nonlinear chipscale nanophotonics in the visible and near-infrared have been largely driven by manipulating the local dielectric environment proximate to decades-old workhorse bulk nonlinear optical materials,…
Due to the absence of interlayer coupling and inversion symmetry, transition metal dichalcogenide (MX$_2$) semiconductor monolayers exhibit novel properties that are distinctly different from their bulk crystals such as direct optical band…
Recent experimental results have demonstrated the ability of monolayer MoS$_2$ to efficiently generate second harmonic fields with susceptibilities between 0.1 and 100 nm/V. However, no theoretical calculations exist with which to interpret…
Silica-based optical fibers are a workhorse of nonlinear optics. They have been used to demonstrate nonlinear phenomena such as solitons and self-phase modulation. Since the introduction of the photonic crystal fiber, they have found many…
The success of isolating small flakes of atomically thin layers through mechanical exfoliation has triggered enormous research interest in graphene and other two-dimensional materials. For device applications, however, controlled large-area…
Materials can, in principle, be imaged at the level of individual atoms with aberration corrected transmission electron microscopy. However, such resolution can be attained only with very high electron doses. Consequently, radiation damage…
Second-order nonlinearity in solids gives rise to a plethora of unique physical phenomena ranging from piezoelectricity and optical rectification to optical parametric amplification, spontaneous parametric down-conversion, and the…
Two-dimensional materials such as graphene and transition metal dichalcogenides (TMDs) are ideal candidates to create ultra-thin electronics suitable for flexible substrates. Although optoelectronic devices based on TMDs have demonstrated…