arXiv subjects

Shamir Rosen

Publications and source records attributed to Shamir Rosen.

4 recordsLinked to original sources

arXiv2015

Experimental tomography of NOON states with large photon numbers

We have performed experimental quantum state tomography of NOON states with up to four photons. The measured states are generated by mixing a classical coherent state with spontaneous parametric down-conversion. We show that this method produces states which exhibit a high fidelity with ideal NOON states. The fidelity is limited by the overlap of the two-photon down-conversion state with any two photons originating from the coherent state, for which we introduce and measure a figure of merit. A second limitation on the fidelity set by the total setup transmission is discussed. We also apply the same tomography procedure for characterizing correlated photon hole states.

quant-ph↗

arXiv2015

Focusing and Scanning through Flexible Multimode Fibers without Access to the Distal End

Multimode fibers (MMFs) are attractive ultra-thin replacements for state-of-the-art endoscopes, but the phase randomization in propagation through MMFs poses a major hurdle for imaging and focusing of light. Recently, this challenge has been addressed by pre-measuring the compensation for the fiber's complex input-output modes relations. Unfortunately, the sensitivity of this approach to fiber bending and temperature variations renders it inappropriate for many applications. Here, we demonstrate a truly endoscopic robust method for controlled in-situ focusing and scanning through a flexible uncharacterized MMF, whereby all the instrumentation is situated at the proximal end. We show that in graded-index (GRIN) fibers, light patterns at the proximal end allow retrieving information about the distal light distribution. We utilize these properties and two-photon fluorescence for robust controlled focusing through bended GRIN fibers. Our results carry potential for lensless two-photon micro-endoscopy.

physics.optics↗

arXiv2012

Sub-Rayleigh lithography using high flux loss-resistant entangled states of light

Quantum lithography achieves phase super-resolution using fragile, experimentally challenging entangled states of light. We propose a scalable scheme for creating features narrower than classically achievable, with reduced use of quantum resources and consequently enhanced resistance to loss. The scheme is an implementation of interferometric lithography using a mixture of an SPDC entangled state with intense classical coherent light. We measure coincidences of up to four photons mimicking multiphoton absorption. The results show a narrowing of the interference fringes of up to 30% with respect to the best analogous classical scheme using only 10% of the non-classical light required for creating NOON states.

quant-ph↗

arXiv2010

Photodarkening of blinking quantum dots is not governed by Auger recombination

The observed intermittent light emission from colloidal semiconductor nanocrystals has long been associated with Auger recombination assisted quenching. We test this view by observing transient emission dynamics of CdSe/CdS/ZnS semiconductor nanocrystals using time-resolved photon counting. The size and intensity dependence of the observed decay dynamics are inconsistent with the those expected from Auger processes. Moreover, the data suggests that in the `off' state the quantum dot cycles in a three-step process: photoexcitation, rapid trapping and subsequent slow nonradiative decay.

cond-mat.mes-hall↗