Estimation of the rate of entangled-photon-pair interaction with metallic nanoparticles based on classical-light second-harmonic generation measurements

Abstract

Entangled-photon-pair interaction (EPPI) with matter is a key element in many suggested quantum-light applications and an enhancement of this interaction is of great importance. In this paper, we suggest and investigate the use of metallic nanoparticles (MNPs), with their exceptional capability of light-matter coupling at their localized surface plasmon resonance, for a potential enhancement of EPPI. We specifically investigate second-harmonic generation and theoretically estimate the rate of EPPI with MNPs using measurements with classical-light. We perform a simple measurement based on approximating the optical-setup factor G, of hyper-Rayleigh scattering. Experimental results, obtained for solutions of silver NPs (SNPs) with different densities, show a hyperpolarizability of about 10 esu . 24-[ ] The results indicate that the use of SNPs can indeed be advantageous for EPPI, with an estimated three orders-of magnitude enhancement of the hyperpolarizability, relative to the best organic molecules. However, we show that further optimization of the SNPs should be carried out to enlarge their EPPI crosssection even more.

Setting bounds on two-photon absorption cross-sections in common fluorophores with entangled photon pair excitation

“…There are other publications in this field that support our findings. In particular, Ashkenazy et al [46], argued that using "typical" values of A e (50 µm 2 ) and T e (50 fs), they can estimate σ E ≈ 10 −29 cm 2 for metallic nanoparticles with a large σ C ≈ 100 GM. Cross-sections of this size are in agreement with our established bounds of σ E .…”

Hot-Band Absorption Can Mimic Entangled Two-Photon Absorption

“…More recently, however, a number of studies have reported conflicting results which cast doubt on the large enhancements claimed in those reports. [15][16][17][18][19] For example, three different groups employed E2PEF measurements to determine the σ E2PA of Rhodamine 6G (Rh6G). 4,20,21 Tabakaev et al 20 measured E2PEF using CW SPDC excitation at 1064 nm with up to 5 × 10 8 pairs/sec.…”

Measurement of the Second-Order Polarizability of Silver Nanoparticles With Reference-Free Hyper-Rayleigh Scattering for Entangled Photon Pair Interaction

“…In [22], Ashkenazy et al have proposed a different approach, a RFHRS method, in which the NPs are modeled as dipoles oscillating at the SH frequency, and the G-factor (for setups in which the SH signal is collected in reflection or transmission) is approximated as:…”

“…These SNPs were embedded in polyvinyl-alcohol (PVA), making it the first report of RFHRS measurements on NPs embedded in a homogenous media and not in a solution. Moreover, unlike previous experimental setups [21,22] in which the transmitted second-harmonic (SH) signal was 2 > REPLACE THIS LINE WITH YOUR MANUSCRIPT ID NUMBER (DOUBLE-CLICK HERE TO EDIT) < measured, in our implementation the SH signal was measured in reflection.…”

“…One suggested way to achieve stronger EPPI is to make use of metallic nanoparticles (NPs), whose localized surfaceplasmon resonance (LSPR) can enhance linear and nonlinear interactions [16][17][18][19][20]. Ashkenazy et al have described how the expected enhancement of EPPI (specifically, SHG) with NPs can be deduced from classical-light SHG measurements performed in a novel reference-free hyper-Rayleigh scattering (RFHRS) method [21,22]. They have shown that, for an aqueous solution of a mixture of triangular and spherical silver NPs (SNPs), LSPR results in NPs having hyperpolarizability that is three orders-of-magnitude larger than best organic molecules.…”