Itai Epstein

Arbitrary Bending Plasmonic Light Waves

We demonstrate the generation of self-accelerating surface plasmon beams along arbitrary caustic curvatures. These plasmonic beams are excited by free-space beams through a two-dimensional binary plasmonic phase mask, which provides the missing momentum between the two beams in the direction of propagation and sets the required phase for the plasmonic beam in the transverse direction. We examine the cases of paraxial and nonparaxial curvatures and show that this highly versatile scheme can be designed to produce arbitrary plasmonic self-accelerating beams. Several different plasmonic beams, which accelerate along polynomial and exponential trajectories, are demonstrated both numerically and experimentally, with a direct measurement of the plasmonic light intensity using a near-field scanning optical microscope.

Dynamic generation of plasmonic bottle-beams with controlled shape

We demonstrate the generation of plasmonic bottle-beams based on self-accelerating surface plasmons. These beams are excited from free-space beams through a special binary phase mask. The mask generates two mirror-imaged self-accelerating surface plasmons, which form the plasmonic bottle-beam and a hot-spot at the point of convergence. The shape and area of the bottle-beams, together with the location of the hot-spot, are statically controlled by designing arbitrary convex trajectories for the two counter-accelerating beams and also are dynamically controlled by the illumination beam.

Polarization controlled coupling and shaping of surface plasmon polaritons by nanoantenna arrays

We demonstrate experimentally the use of ordered arrays of nanoantennas for polarization controlled plasmonic beam shaping and excitation. Rod- and cross-shaped nanoantennas are used as local point-like sources of surface plasmon polaritons, and the desired phase of the generated plasmonic beam is set directly through their spatial arrangement. The polarization selectivity of the optical nanoantennas allows us to further control the excitation, enabling the realization of a variety of complex and functional plasmonic beam shaping elements. We demonstrate this concept by generating plasmonic self-accelerating beams, plasmonic bottle beams, and switchable dual-focii plasmonic lenses. The freedom in the design and arrangement of these nanoantennas enables us to specifically tailor and control the shapes, wavelengths, and coupling efficiencies of complex plasmonic beams.

A 1.3 Tb/s parallel optics VCSEL link

A high bandwidth optical interconnect is designed based on parallel optical VCSEL links. Large matrices with 168 data channels are utilized exhibiting the highest reported full duplex aggregate bandwidth of 1.34Tb/s. Optical links of 300m are measured with BER < 10-12 while the power efficiency is 10.2 pJ/bit. The interconnect design is that of hybrid device with the III-V optoelectronics assembled directly onto the ASIC using Au/Sn eutectic bonding. Optical packaging is enabled using fiber bundle matrices whose dimensions are identical to those of the optoelectronic chips. The entire chip is assembled onto a system PCB in telecom and datacom applications. The backplane of the system becomes passive optical backplane and is entirely fiber based. The hybrid integration allows for a 3-fold increase in the number of SerDes available on a single package to about 500 lanes.

Arbitrary holographic spectral shaping of plasmonic broadband excitations

We demonstrate a new method for controlling the broadband excitations of surface plasmons. This method is based on computer-generated holographic gratings and enables not only the coupling of the broadband illumination with surface plasmons, but also the arbitrary shaping of their spectra. As an example, we demonstrate several spectral shapes numerically and measure them experimentally, finding a good agreement with the simulation results. In addition, we show the potential for shaping the plasmonic spatial profile simultaneously with its spectral profile. This method may be useful for on-chip communication and light filtering as well as for sensing and temporal manipulation of ultrashort pulses.

Generation of intensity-controlled two-dimensional shape-preserving beams in plasmonic lossy media

Two-dimensional surface-plasmon polariton waves, which propagate at a metal/dielectric interface, exhibit unique and attractive properties. These extraordinary properties, however, are accompanied by fundamentally inherent losses. The latter is probably the most pronounced challenge in the field of plasmonics and a true bottleneck for many applications. Shape-preserving beams, on the other hand, are unique solutions of the wave equation; they maintain their shape with propagation and also possess the ability to self-reconstruct. Here, we study the first realization of surface-plasmon shape-preserving beams, which maintain their shape and intensity over long distances, even when subjected to plasmonic losses. Moreover, their intensity distribution along propagation can be arbitrarily tailored. This is achieved without the use of any gain media, but rather by strictly controlling the initial plasmonic wavefront. This approach can be valuable for a variety of plasmonic applications, such as surface particle trapping and manipulation, on-chip communication, nonlinear optics, and more.

Observation of linear plasmonic breathers and adiabatic elimination in a plasmonic multi-level coupled system

We provide experimental and numerical demonstrations of plasmonic propagation dynamics in a multi-level coupled system, and present the first observation of plasmonic breathers propagating in such systems. The effect is observed both for the simplest symmetric case of a thin metal layer surrounded by two identical dielectrics, and also for a more complex system that includes five and more layers. By a careful choice of the permittivities and thicknesses of the intermediate layers, we can adiabatically eliminate the plasmonic waves in all the intermediate interfaces, thus enabling efficient vertical delivery and extraction of plasmonic signals between the top layer and deeply buried layers. The observation relies on controlling the excited mode by breaking the symmetry of excitation, which is crucial for obtaining the results experimentally. We also observe this breathing effect for transversely shaped plasmonic beams, with Hermite-Gauss, Airy and Weber wavefronts, that despite the oscillatory nature of propagation in such systems, still preserve all their unique wavefront properties. Finally, we show that such approaches can be extended to plasmonic propagation in a general multi-layered system, opening a path for efficient three-dimensional integrated plasmonic circuitry.

Controlling surface plasmon propagation by tilted optical beams incident on a 1D grating

Tailoring the properties of an optical beam incident on a one dimensional metallic grating can attain a substantial control over the excited surface plasmon polariton wave. In this work we derive the complete analytical relations between the optical angles of incidence and the resulting surface plasmon propagation angle. These relations are demonstrated both numerically and experimentally. Following we show that there is an optimal grating that can excite any surface plasmon propagation angle between ±82.46 degrees and efficient polarization schemes which lead to negligible losses. Finally we introduce a formalism that relates general surface plasmon beams to corresponding incident optical beams and using it we demonstrate numerically a varying position surface plasmon hotspot generation.

Compensating Plasmonic Losses by Wavefront Manipulation

We demonstrate experimentally the generation of unique surface-plasmon beams, which compensate the inherent losses of plasmons without using gain media, and show that these beams can extend the limited propagation length of surface-plasmons.