Femtosecond Laser-written Waveguide Arrays Research Articles

Rogue waves in disordered 1D photonic lattices

In this work, we study the phenomena of Rogue waves (RW) on one-dimensional (1D) photonic lattices presenting diagonal and non-diagonal disorder. Our results show the appearance of extreme events coming from the superposition of different, extended and localized, linear waves for weak disorder. We perform experiments on femtosecond laser written waveguide arrays having disorder in coupling constants, which is originated from a random waveguide distribution. Both, numerics and experiments, are in good agreement and show that RW are generically present in 1D lattices for weak disorder only, after a mandatory data filtering process.

Nonlinear symmetry breaking of Aharonov-Bohm cages

We study the influence of mean field cubic nonlinearity on Aharonov-Bohm caging in a diamond lattice with synthetic magnetic flux. For sufficiently weak nonlinearities the Aharonov-Bohm caging persists as periodic nonlinear breathing dynamics. Above a critical nonlinearity, symmetry breaking induces a sharp transition in the dynamics and enables stronger wavepacket spreading. This transition is distinct from other flatband networks, where continuous spreading is induced by effective nonlinear hopping or resonances with delocalized modes, and is in contrast to the quantum limit, where two-particle hopping enables arbitrarily large spreading. This nonlinear symmetry breaking transition is readily observable in femtosecond laser-written waveguide arrays.

Observation of discrete solitons in lattices with second-order interaction

We present what we believe to be the first experimental demonstration of discrete solitons under the influence of first- and second-order lattice site interaction in zigzag femtosecond laser-written waveguide arrays. We show how the formation of these entities is affected by different ratios of the interaction strength. Increasing the second-order coupling between the lattices sites yields an almost linear increase of the input power required for soliton formation.

Bloch-Zener Oscillations in Binary Superlattices

Bloch-Zener oscillations, i.e., the coherent superposition of Bloch oscillations and Zener tunneling between minibands of a binary lattice, are experimentally demonstrated for light waves in curved femtosecond laser-written waveguide arrays. Visualization of double-periodicity breathing and oscillation modes is reported, and synchronous tunneling leading to wave reconstruction is demonstrated.

Image reconstruction in segmented femtosecond laser-written waveguide arrays

We present the first experimental realization of image reconstruction in finite femtosecond laser-written waveguide arrays with segmentation. The results show that arbitrary field distributions can be imaged in one-dimensional as well as in two-dimensional geometries.

Decay Control via Discrete-to-Continuum Coupling Modulation in an Optical Waveguide System

Control of optical tunneling via modulation of the coupling to the continuum is experimentally reported in femtosecond laser written waveguide arrays. The experiment demonstrates for optical tunneling in photonic lattices the universal mechanism of decay control recently proposed for quantum systems by Kofman and Kurizki [Phys. Rev. Lett. 87, 270405 (2001)]. In particular, we prove that the formation of a dressed discrete-continuum bound state in the regime of fractional decay can be suppressed by dynamic modulation of discrete-to-continuum coupling.

Fresnel's laws in discrete optical media

We present the discrete analog of Snell's refraction law at the interface between two dissimilar waveguide arrays. Additionally, reflection and transmission coefficients for the Bloch waves are derived analytically. The theoretical findings were confirmed by analyzing the evolution of light in femtosecond laser written waveguide arrays.

Observation of Two-Dimensional Surface Solitons in Asymmetric Waveguide Arrays

We report on the experimental observation of two-dimensional surface waves localized at the edge or in the corner of femtosecond laser-written waveguide arrays in fused silica. Increasing the power of the input beam allows one to observe a clear transition from a linear diffraction pattern to localized nonlinear surface states, which can exist at the interface only above a certain power threshold. This constitutes the first ever experimental observation of two-dimensional nonlinear surface solitons in optics.