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We demonstrate second order optical nonlinearity in aluminum nitride on insulator substrates. Using sputter-deposited aluminum nitride thin films we realize nanophotonic waveguides coupled to micro-ring resonators that simultaneously…

Optics · Physics 2012-06-13 W. H. P. Pernice , C. Xiong , C. Schuck , H. X. Tang

We report experimental results on second-harmonic generation in a z-cut quartz crystal under conditions of free-space quasi-phase matching in a multi-pass cell. In a 62-pass configuration, an efficiency of 0.027% or 1.4x10-4 %/MW/cm2 was…

Optics · Physics 2026-04-10 Nazar Kovalenko , Ankit Pai , Oleg Pronin

We report on double-resonant highly efficient sum-frequency generation in the blue range. The system consists of a 10-mm-long periodically poled KTP crystal placed in a double-resonant bow-tie cavity and pumped by a fiber laser at 1064.5 nm…

High-$Q$ optical nanocavities are fundamental to modern optics and photonics, enabling enhanced light-matter interactions. Previous studies have demonstrated that high-$Q$ supercavity modes can be constructed within a single dielectric…

Optics · Physics 2026-01-21 Xu Tu , Meibao Qin , Huifu Qiu , Feng Wu , Tingting Liu , Lujun Huang , Shuyuan Xiao

Second harmonic generation (SHG) extensively employs periodically poled nonlinear crystals through forward quasi-phase-matching to achieve efficient frequency conversion. As poling periods approach sub-micrometers, backward…

Optics · Physics 2024-07-15 Fengyan Yang , Juanjuan Lu , Mohan Shen , Guangcanlan Yang , Hong X. Tang

In this letter we experimentally demonstrate second harmonic conversion in the opaque region of a GaAs cavity with efficiencies of the order of 0.1% at 612nm, using 3ps pump pulses having peak intensities of order of 10MW/cm2. We show that…

Optics · Physics 2010-10-25 V. Roppo , F. Raineri , C. Cojocaru , R. Raj , J. Trull , I. Sagnes , R. Vilaseca , M. Scalora

Multi-longitudinal-mode lasers have been believed to be good candidates as pump sources for optical frequency conversion. However, we present a semi-classical model for frequency conversion of optical signals with a multimode pump laser,…

Optics · Physics 2015-06-04 J. S. Pelc , G. -L. Shentu , Q. Zhang , M. M. Fejer , J. -W. Pan

Nonlinear frequency conversion in optics can originate the coherent light at the wavelength where it is hard or unlikely to achieve by directly lasing and is a fundamental topic in science and engineering covering both classical and quantum…

Optics · Physics 2019-12-02 Mingchuan Shao , Fei Liang , Haohai Yu , Huaijin Zhang

Quasi-phasematched interactions in waveguides with quadratic nonlinearities enable highly efficient nonlinear frequency conversion. In this article, we demonstrate the first generation of devices that combine the dispersion-engineering…

We propose and experimentally demonstrate a scheme allowing to reach noncollinear phase-matching of high harmonic generation in solids, which may potentially lead to an enhancement of the generation efficiency. The principle is based on…

Optics · Physics 2026-02-24 Pavel Peterka , František Trojánek , Petr Malý , Martin Kozák

Quantum repeaters rely on an interfacing of flying qubits with quantum memories. The most common implementations include a narrowband single photon matched in bandwidth and central frequency to an atomic system. Previously, we demonstrated…

Microresonators are powerful tools to enhance the efficiency of second-order nonlinear optical processes, such as second-harmonic generation, which can coherently bridge octave-spaced spectral bands. However, dispersion constraints such as…

On-chip bright quantum sources with multiplexing ability are extremely high in demand for the integrated quantum networks with unprecedented scalability and complexity. Here, we demonstrate an ultrabright and broadband biphoton quantum…

Typical microresonators exhibit a large frequency spacing between resonances and a limited tunability. This impedes their use in a large class of applications which require a resonance of the microcavity to coincide with a predetermined…

Optics · Physics 2010-07-06 M. Pöllinger , D. O'Shea , F. Warken , A. Rauschenbeutel

We demonstrate supermode-based second harmonic generation in an integrated nonlinear interferometer made of linear and nonlinear directional couplers. We use a fully-fibered pump shaper to demonstrate second harmonic generation pumped by…

In whispering gallery mode (WGM) resonators light is guided by continuous total internal reflection along a curved surface. Fabricating such resonators from an optically nonlinear material one takes advantage of their exceptionally high…

Optical whispering-gallery microresonators are useful tools in microphotonics, and nonlinear optics at very low threshold powers. Here, we present details about the fabrication of ultra-high-Q whispering-gallery-mode resonators made by…

Optics · Physics 2015-06-16 Pascal Del'Haye , Scott A. Diddams , Scott B. Papp

Improving the conversion efficiency is critical for advancing nonlinear photonic devices, enabling applications in ultrafast optics, quantum light sources, and high-resolution imaging. Herein, we present a bilayer waveguide integrated with…

Optics · Physics 2025-08-21 Xin Huang , Qi Lin , Sheng-Xuan Xia , Xiang Zhai , Gui-Dong Liu

We report the observation of second-harmonic generation in stoichiometric silicon nitride waveguides grown via low-pressure chemical vapour deposition. Quasi-rectangular waveguides with a large cross section were used, with a height of 1…

Second harmonic conversion from 1550~nm to 775~nm with an efficiency of 400% W$^{-1}$ is demonstrated in a gallium phosphide (GaP) on oxide integrated photonic platform. The platform consists of doubly-resonant, phase-matched ring…