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Junqiu Liu

Cette personne a quitté l’EPFL

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Publications associées (146)

Page 3 sur 8

Nanophotonic supercontinuum-based mid-infrared dual-comb spectroscopy

Luc Thévenaz, Tobias Kippenberg, Camille Sophie Brès, Junqiu Liu, Hairun Guo, Wenle Weng, Wolfgang Hänsel

High resolution and fast detection of molecular vibrational absorption is important for organic synthesis, pharmaceutical processes, and environmental monitoring, and is enabled by mid-infrared (mid-IR) laser frequency combs via dual-comb spectroscopy. Her ...

2020

Advanced dispersion engineering of dispersive waves in Si3N4 microresonators

Tobias Kippenberg, Junqiu Liu, Maxim Karpov, Anton Lukashchuk

We experimentally demonstrate the possibility of dispersive wave tuning via advanced dispersion engineering. We utilize hybridized modes of concentric coupled resonators for precise control of the dispersion profile. (C) 2019 The Author(s) ...

IEEE2019

Observation of Stimulated Brillouin Scattering in Silicon Nitride Integrated Waveguides

Luc Thévenaz, Tobias Kippenberg, Junqiu Liu, Rui Ning Wang, Jijun He, Arslan Sajid Raja, Flavien Gyger, Fan Yang

Silicon nitride (Si3N4) has emerged as a promising material for integrated nonlinear photonics and has been used for broadband soliton microcombs and low-pulse-energy supercontinuum generation. Therefore, understanding all nonlinear optical properties of S ...

2020

Photonic microwave generation in the X- and K-band using integrated soliton microcombs

Tobias Kippenberg, Junqiu Liu, Maxim Karpov, Rui Ning Wang, Johann Emmeram Riemensberger, Hairun Guo, Erwan Guillaume Albert Lucas, Jijun He, Arslan Sajid Raja, Romain Dany Bruno Bouchand

Microwave photonic technologies, which upshift the carrier into the optical domain, have facilitated the generation and processing of ultra-wideband electronic signals at vastly reduced fractional bandwidths. For microwave photonic applications such as rad ...

Nature Publishing Group2020

Low-noise, Frequency-agile, Hybrid Integrated Laser for LiDAR

Tobias Kippenberg, Junqiu Liu, Rui Ning Wang, Johann Emmeram Riemensberger, Wenle Weng, Jijun He, Anat Siddharth, Viacheslav Snigirev

We demonstrate a hybrid photonic integrated laser with intrinsic linewidth of 40 Hz, while offering megahertz actuation bandwidth with the tuning range larger than 1 GHz, attained by a DFB laser self-injection locking to a high-Q Si3N4 microresonator with ...

IEEE2021

Ultralow-Power Photonic Chip-Based Soliton Frequency Combs

Tobias Kippenberg, Junqiu Liu, Maxim Karpov, Martin Hubert Peter Pfeiffer, Hairun Guo, Arslan Sajid Raja, Michail Zervas, Nils Johan Engelsen, Bahareh Ghadiani

The generation of dissipative Kerr solitons in optical microresonators allow compact high repetition rate frequency combs. A particularly promising platform is photonic integrated Si3N4 microresonators. Yet to date, soliton formation in Si3N4 microresonato ...

IEEE2018

Thermorefractive noise in silicon-nitride microresonators

Tobias Kippenberg, Junqiu Liu, Erwan Guillaume Albert Lucas, Arslan Sajid Raja, Guanhao Huang, Nils Johan Engelsen

Thermodynamic noise places a fundamental limit on the frequency stability of dielectric optical resonators. Here, we present the characterization of thermorefractive noise in photonic-chip-based silicon-nitride (Si3N4) microresonators and show that thermor ...

AMER PHYSICAL SOC2019

Platicon microcomb generation using laser self-injection locking

Tobias Kippenberg, Junqiu Liu, Rui Ning Wang, Wenle Weng, Jijun He, Miles Henry Anderson

The past decade has witnessed major advances in the development and system-level applications of photonic integrated microcombs, that are coherent, broadband optical frequency combs with repetition rates in the millimeter-wave to terahertz domain. Most of ...

Nature Portfolio2022

Coupling Free Electrons and Cavity Photons in a Transmission Electron Microscope

Tobias Kippenberg, Junqiu Liu, Rui Ning Wang, Arslan Sajid Raja, Guanhao Huang, Zheru Qiu, Yujia Yang

We couple free electrons to the optical modes of a photonic microring resonator. Inelastic electron scattering leads to the generation of cavity photons, correlated to the electrons in time and energy loss. ...

Institute of Electrical and Electronics Engineers Inc.2024

Photonic Integrated K-Band Microwave Oscillator Based on Silicon Nitride Soliton Microcomb

Tobias Kippenberg, Junqiu Liu, Maxim Karpov, Rui Ning Wang, Hairun Guo, Erwan Guillaume Albert Lucas, Arslan Sajid Raja, Jijun He, Guanhao Huang, Nils Johan Engelsen, Romain Dany Bruno Bouchand

Using photonic integrated silicon nitride microresonators of quality factor exceeding 15 million, we demonstrate 19-GHz-repetition-rate single soliton with 35 mW optical power, and characterize the phase noise of the repetition rate in the K-band microwave ...

IEEE2019

Highly efficient coupling of crystalline microresonators to integrated photonic waveguides

Tobias Kippenberg, Michail Zervas, Junqiu Liu, Miles Henry Anderson, John David Jost

Crystalline optical whispering gallery mode resonators made from alkaline earth fluorides can achieve exceptionally large optical finesse, and are used in a variety of applications, from frequency stabilization and narrow linewidth lasers, to low-noise mic ...

2018

Generation of OH radicals at palladium oxide nanoparticle modified electrodes, and scavenging by fluorescent probes and antioxidants

Hubert Girault, Junqiu Liu

The reduction of palladium oxide nanoparticles in the presence of hydrogen peroxide or dissolved oxygen gives rise to a catalytic reduction current dependent on the hydrogen peroxide concentration or the oxygen concentration. Using terephthalic acid as an ...

2008

Gain-switched semiconductor laser driven soliton microcombs

Tobias Kippenberg, Junqiu Liu, Erwan Guillaume Albert Lucas, Wenle Weng, Jijun He

Using phase-engineered coherent laser pulses produced by gain-switched semiconductor lasers, we generate low-power-threshold soliton microcombs whose repetition frequencies are in the X-band and K-band microwave ranges. (c) 2021TheAuthor(s) ...

IEEE2021

Hybrid integrated photonics using bulk acoustic resonators

Tobias Kippenberg, Junqiu Liu, Michail Zervas

Integrated photonic devices based on Si3N4 waveguides allow for the exploitation of nonlinear frequency conversion, exhibit low propagation loss, and have led to advances in compact atomic clocks, ultrafast ranging, and spectroscopy. Yet, the lack of Pocke ...

Nature Research2020

Probing material absorption and optical nonlinearity of integrated photonic materials

Tobias Kippenberg, Junqiu Liu, Guanhao Huang

Optical microresonators with high quality (Q) factors are essential to a wide range of integrated photonic devices. Steady efforts have been directed towards increasing microresonator Q factors across a variety of platforms. With success in reducing microf ...

Nature Portfolio2022

Self-injection Locked Second-Harmonic Generation in Optically Poled Silicon Nitride Microresonators

Tobias Kippenberg, Camille Sophie Brès, Junqiu Liu, Edgars Nitiss, Marco Clementi

We present a narrow-linewidth second-harmonic source based on a laser diode injection locked to an optically poled silicon nitride microresonator. The device is a compact, highly-coherent dual-wavelength source, with high conversion efficiency up to 280%/W ...

2023

Nano-photonic Supercontinuum Based Mid-Infrared Dual-Comb Spectroscopy

Luc Thévenaz, Tobias Kippenberg, Camille Sophie Brès, Junqiu Liu, Hairun Guo, Wenle Weng, Fan Yang

We demonstrate an approach to dual-comb spectroscopy, based on dispersion engineered and ultra-broadband supercontinuum generation in photonic integrated nonlinear waveguides, and driven by low-noise fiber-laser combs. Both technologies arc statc-of-the-ar ...

IEEE2020

Magnetic-free Nitride Optical Isolator on Chip

Tobias Kippenberg, Junqiu Liu, Rui Ning Wang, Jijun He, Anat Siddharth, Terence Albert Emile Blésin

We demonstrated a magnetic-free optical isolator for Si3N4 photonics using AlN piezoelectric actuators. Maximum of 10 dB isolation and

IEEE2021

Nonlinear Frequency Conversion in the Hybrid Silicon Nitride - Lithium Niobate Integrated Platform

Tobias Kippenberg, Junqiu Liu, Rui Ning Wang, Mikhail Churaev, Viacheslav Snigirev, Terence Albert Emile Blésin

We demonstrate optical frequency comb generation in hybrid high-Q optical microresonators fabricated using direct wafer bonding of photonic Damascene silicon nitride wafer with thin-film lithium niobate-on-insulator (LNOI). The devices enable direct phase ...

IEEE2021

Photo-induced cascaded harmonic and comb generation in silicon nitride microresonators

Tobias Kippenberg, Camille Sophie Brès, Junqiu Liu, Wenle Weng, Jijun He, Jianqi Hu, Edgars Nitiss, Ozan Yakar

Silicon nitride (Si3N4) is an ever-maturing integrated platform for nonlinear optics but mostly considered for third-order [chi(3)] nonlinear interactions. Recently, second-order [chi(2)] nonlinearity was introduced into Si3N4 via the photogalvanic effect, ...

2022