English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The miniaturization of nonlinear light sources is central to the integratedphotonic platform, driving a quest for high-efficiency frequency generation andmixing at the nanoscale. In this quest, the high-quality ($Q$) resonantdielectric nanostructures hold great promise, as they enhance nonlinear effectsthrough the resonantly local electromagnetic fields overlapping the chosennonlinear materials. Here, we propose a method for the enhanced sum-frequencygeneration (SFG) from etcheless lithium niobate (LiNbO$_{3}$) by utilizing thedual quasi-bound states in the continuum (quasi-BICs) in a one-dimensionalresonant grating waveguide structure. Two high-$Q$ guided mode resonancescorresponding to the dual quasi-BICs are respectively excited by twonear-infrared input beams, generating a strong visible SFG signal with aremarkably high conversion efficiency of $3.66\times10^{-2}$ (five orders ofmagnitude higher than that of LiNbO$_{3}$ films of the same thickness) and asmall full-width at half-maximum less than 0.2 nm. The SFG efficiency can betuned via adjusting the grating geometry parameter or choosing the input beampolarization combination. Furthermore, the generated SFG signal can bemaintained at a fixed wavelength without the appreciable loss of efficiency byselectively exciting the angle-dependent quasi-BICs, even if the wavelengths ofinput beams are tuned within a broad spectral range. Our results provide asimple but robust paradigm of high-efficiency frequency conversion on aneasy-fabricated platform, which may find applications in nonlinear lightsources and quantum photonics.

Enhanced sum-frequency generation from etchless lithium niobate empowered by dual quasi-bound states in the continuum