Publications

2014
Liron Stern, Meir Grajower, and Uriel Levy. 2014. “Fano resonances and all-optical switching in a resonantly coupled plasmonic–atomic system.” Nature Communications, 5. Abstract
The possibility of combining atomic and plasmonic resonances opens new avenues for tailoring the spectral properties of materials. Following the rapid progress in the field of plasmonics, it is now possible to confine light to unprecedented nanometre dimensions, enhancing light–matter interactions at the nanoscale. However, the resonant coupling between the relatively broad plasmonic resonance and the ultra-narrow fundamental atomic line remains challenging. Here we demonstrate a resonantly coupled plasmonic–atomic platform consisting of a surface plasmon resonance and rubidium (85Rb) atomic vapour. Taking advantage of the Fano interplay between the atomic and plasmonic resonances, we are able to control the lineshape and the dispersion of this hybrid system. Furthermore, by exploiting the plasmonic enhancement of light–matter interactions, we demonstrate all-optical control of the Fano resonance by introducing an additional pump beam.
2013
Jonathan Bar-David, Gilad M. Lerman, Liron Stern, Noa Mazurski, and Uriel Levy. 2013. “Generation of a periodic array of radially polarized Plasmonic focal spots.” Optics Express. Abstract
This paper demonstrates experimentally the tight focusing of a 3X3 array of radially polarized diffraction orders, and the coupling of this array of spots to surface plasmon polaritons (SPPs), propagating on a uniform metal film, and effectively generating a periodic structure of plasmonic sources by the use of structured illumination pattern, rather than by structuring the plasmonic sample. Using near field measurements, we observed coherent interactions between these multiple plasmonic sources as they propagate towards each other. The demonstrated setup exploits the previously demonstrated advantages of radially polarized light in coupling to SPPs and in generating sharper plasmonic hot spots and expends its use towards mitigating parallel processing challenges. The experimental results are in good agreement with the theory, showing interference fringes having periodicity compatible with the plasmonic SPP wavelength. The demonstrated approach of generating array of hot spots on flat metallic films is expected to play a role in variety of applications, e.g. microscopy, lithography, sensing and optical memories.
Liron Stern, Boris Desiatov, Ilya Goykhman, and Uriel Levy. 2013. “Nanoscale light–matter interactions in atomic cladding waveguides.” Nature Communications, 4, Pp. 1548. Abstract
Alkali vapours, such as rubidium, are being used extensively in several important fields of research such as slow and stored light nonlinear optics quantum computation, atomic clocks and magnetometers. Recently, there is a growing effort towards miniaturizing traditional centimetre-size vapour cells. Owing to the significant reduction in device dimensions, light–matter interactions are greatly enhanced, enabling new functionalities due to the low power threshold needed for nonlinear interactions. Here, taking advantage of the mature platform of silicon photonics, we construct an efficient and flexible platform for tailored light–vapour interactions on a chip. Specifically, we demonstrate light–matter interactions in an atomic cladding waveguide, consisting of a silicon nitride nano-waveguide core with a rubidium vapour cladding. We observe the efficient interaction of the electromagnetic guided mode with the rubidium cladding and show that due to the high confinement of the optical mode, the rubidium absorption saturates at powers in the nanowatt regime.
Alexandros Emboras, Ilya Goykhman, Boris Desiatov, Noa Mazurski, Liron Stern, Joseph Shappir, and Uriel Levy. 2013. “Nanoscale Plasmonic Memristor with Optical Readout Functionality.” Nano Letters. Abstract
We experimentally demonstrate for the first time a nanoscale resistive random access memory (RRAM) electronic device integrated with a plasmonic waveguide providing the functionality of optical readout. The device fabrication is based on silicon on insulator CMOS compatible approach of local oxidation of silicon, which enables the realization of RRAM and low optical loss channel photonic waveguide at the same fabrication step. This plasmonic device operates at telecom wavelength of 1.55 ?m and can be used to optically read the logic state of a memory by measuring two distinct levels of optical transmission. The experimental characterization of the device shows optical bistable behavior between these levels of transmission in addition to well-defined hysteresis. We attribute the changes in the optical transmission to the creation of a nanoscale absorbing and scattering metallic filament in the amorphous silicon layer, where the plasmonic mode resides.
2012
Liron Stern, Ilya Goykhman, Boris Desiatov, and Uriel Levy. 2012. “Frequency locked micro disk resonator for real time and precise monitoring of refractive index.” Optics Letters, 37, 8, Pp. 1313–1315. Abstract
We experimentally demonstrate a frequency modulation locked servo loop, locked to a resonance line of an on-chip microdisk resonator in a silicon nitride platform. By using this approach, we demonstrate real-time monitoring of refractive index variations with a precision approaching 10−7  RIU, using a moderate Q factor of 104. The approach can be applied for intensity independent, dynamic and precise index of refraction monitoring for biosensing applications.
In this paper we analyze the transmission and time delay properties of light propagating through a microring resonator (MRR) consisting of a solid core waveguide surrounded by an atomic vapor cladding. Using the atomic effective susceptibility of Rubidium we derive the complex transmission spectrum of the integrated system. We show, that when the system is under-coupled, the transmission can exceed the standalone MRR's background transmission and is accompanied by enhanced positive time delay. It is shown that in this case the contrast of the atomic lines is greatly enhanced. This allows achieving high optical densities at short propagation length. Furthermore, owing to its features such as small footprint, high tunability, and high delay-transmission product, this system may become an attractive choice for chip scale manipulations of light.
2011
L Stern, B Desiatov, I Goykhman, GM Lerman, and U Levy. 2011. “Near field phase mapping exploiting intrinsic oscillations of aperture NSOM probe.” Opt. Express, 19, Pp. 12014–12020.
2010
Gilad M Lerman, Liron Stern, and Uriel Levy. 2010. “Generation and tight focusing of hybridly polarized vector beams.” Optics express, 18, 26, Pp. 27650–27657.
2009
Liron Stern, Avinoam Stern, and Benny Levy. 2009. “The Nano-Atomic-Clock.” In 2009 IEEE International Conference on Microwaves, Communications, Antennas and Electronics Systems, Pp. 1–1. IEEE.

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