Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · 2409.06825

Synthesis by Size Focusing of Lithium Tantalate Nanoparticles with a Tunable Second Harmonic Optical Activity

Rana Faryad Ali·Byron D. Gates
View original source ↗Read source document ↗Export metadata ↓

Abstract

Nonlinear optics at the nanoscale has emerged as a sought-after platform for sensing and imaging applications. The development of these materials is having an impact on fields that include advanced information technology, signal processing circuits, and cryptography. Lithium tantalate (LiTaO3) is an attractive nonlinear optical material due to its high optical damage threshold (e.g., tolerance to greater than 500 MW per cm^2 from a nanosecond pulsed laser) and broad range of ultraviolet-visible (UV-Vis) transparency relative to many other nonlinear optical materials. Despite many synthetic reports on metal oxides, very little is known about the preparation of uniform, crystalline LiTaO3 nanoparticles (NPs) of a pure phase, as well as details on their mechanism of nucleation and growth. In this article, we introduce a solution-phase method for the preparation of LiTaO3 NPs with tunable dimensions. This solution-phase process results in the formation of crystalline, uniform NPs of LiTaO3 of a pure phase when carried out at 220 C. This method can prepare crystalline LiTaO3 NPs without the need for further heat treatment or the use of an inert atmosphere. Results presented herein also provide insights into the growth mechanism of these NPs. The reaction included the processes of oriented attachment and Ostwald ripening. The results of our study also indicate that the growth of the LiTaO3 NPs was a result of a size focusing effect, which enables the ability to tune their diameters from 200 to 500 nm. The crystalline NPs were optically active towards second harmonic generation. These studies deepen our understanding of the methods by which NPs can be prepared from metal oxides. These studies specifically demonstrate the preparation of optically active LiTaO3 NPs of uniform and controllable dimensions that could be used in a broad range of fundamental studies and applications in nanophotonics.

Explore related subjects

physics.optics

Keep this discovery

BibTeXRIS

Rana Faryad Ali, Byron D. Gates. 2024-09-10. Synthesis by Size Focusing of Lithium Tantalate Nanoparticles with a Tunable Second Harmonic Optical Activity. https://doi.org/10.1039/d4tc03938f

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Two-step high-accuracy microwave frequency measurement and time-frequency analysis based on optical frequency combs

Broadband microwave frequency measurement and time-frequency analysis are crucial for applications such as electronic warfare. However, when it comes to ultra wideband signal analysis, traditional electronic methods have high analysis accuracy, but intrinsic electronic bottlenecks limit their real-time analysis. Here, we propose and experimentally demonstrate a two-step microwave frequency measurement and time-frequency analysis method based on optical frequency combs. The system first performs coarse frequency localization over the 0-40 GHz range using stimulated-Brillouin-scattering-assisted frequency-to-time mapping (FTTM) and dual-comb channelized reception. The dual-comb is then reapplied for downconverting the signal under test, followed by digital signal processing to achieve high-accuracy unambiguous frequency extraction. Experimental results show that the system achieves mean single-tone frequency measurement errors of less than 10 kHz over 0-40 GHz. We further experimentally measure multi-tone, linearly frequency-modulated, and V-shaped frequency-modulated signals, demonstrating the proposed method's capability for analyzing complex signals.

physics.optics↗
arXiv2026

A Two-Mirror Faceted Projection System for EUV Lithography

We propose an all-reflective two-mirror projection system for extreme ultraviolet (EUV) lithography operating at exposure wavelengths of $13.5$~nm (Mo/Si) and $11.2$~nm (Ru/Be), delivering a fourfold ($4\times$) demagnification of the periodic mask pattern at a numerical aperture approaching unity ($\mathrm{NA}_{\max} \approx 0.993$). In contrast to conventional EUV projection objectives that incorporate 6--10 aspheric mirrors with an overall optical throughput of less than $15\%$, the proposed design redirects each accepted discrete spatial diffraction order scattered by the mask onto the wafer via a dedicated pair of planar mirror facets. The number of reflections is strictly fixed at two for all accepted orders, retaining $50$--$60\%$ of the power leaving the mask in each accepted order. We derive a spatial geometry providing rigorous optical path length equalization across all diffraction orders, thereby removing order-dependent propagation phase shifts. Individually optimized 30-bilayer Bragg multilayer coatings are designed for each facet using the transfer matrix method combined with global evolutionary optimization algorithms. The architecture is generalized to a three-dimensional vector formulation with a two-dimensionally periodic mask. Utilizing inverse lithography technology, Fourier parameterization, and a differentiable electromagnetic modal waveguide solver, we solve the synthesis problem for binary absorber masks (La absorber on a Ru/Be/Sr multilayer mirror). We demonstrate simulated aerial images of sub-10-nm features on the wafer (isolated peaks with a full width at half maximum (FWHM) of approximately $5.4$~nm and line pairs with a critical dimension of $6$~nm) and find that the two peaks remain resolved for the tested wafer defocus values from $0$ to $5$~nm along the $z$-axis.

physics.optics↗
arXiv2026

Antimony for broadband nanophotonics across the ultraviolet, visible and infrared

Semimetal elemental antimony (Sb) nanostructures show great potential for applications where nanophotonic properties play a key role, such as phase-change optical memories, non-linear optical elements, photothermal therapy agents, photodetectors and photocatalysts. However, designing advanced Sb-based photonic devices critically requires an accurate and reliable knowledge of the optical response of bulk and nanoscale Sb. Herein, we report for the first time a fully consistent and accurately measured dielectric function for Sb nanoscale films in a wide spectral range from the ultraviolet to the far infrared (4 - 0.04 eV, i.e. ~ 0.3 - 30 $\mu$m), surpassing previous reports that explored a limited spectral range. It is found that the Sb spectral response is driven exclusively by giant interband transitions in the visible up to mid infrared (4 - 0.4 eV, i.e. ~ 0.3 - 3 $\mu$m), and that their contribution dominates over that of free carriers down to 0.12 eV (i.e. ~ 10 $\mu$m). Such spectral response enables Sb nanostructures to display spectrally selective and tunable nanophotonic resonances. First, we showcase interband plasmonic resonances in the visible-to-near infrared for Sb nanogratings. Second, we report giant refractive index dielectric resonances in the mid infrared for nanostructured Sb/dielectric/metal resonant cavities. These findings open a pathway to optimized planar Sb nanoscale designs enabling a tailored light-matter interaction, which will be useful for integrated data, telecom, medical, optoelectronic and energy conversion devices operating in a broad spectral range.

physics.optics↗