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Li Zhang

Cette personne a quitté l’EPFL

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Publications associées (40)

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Iron Resonant Photoemission Spectroscopy on Anodized Hematite Points to Electron Hole Doping during Anodization

Michael Graetzel, Philippe Wyss, Kevin Sivula, Li Zhang

Anodization of a-Fe2O3 (hematite) electrodes in alkaline electrolyte under constant potential conditions the electrode surface in a way that an additional current wave occurs in the cyclic voltammogram. The energy position of this current wave is closely b ...

Wiley-Blackwell2012

Sum-Frequency Scattering Spectroscopy Reveals the Charging Mechanism and Surface Structure of hBN Nanoflakes in Solution

Aleksandra Radenovic, Sylvie Roke, Li Zhang, Nathan Cyprien Arsène Ronceray, Benjamin Rehl

A molecular understanding of the interactions between two-dimensional (2D) layered materials and liquids is crucial for nanofluidics, catalysis, and solution-based 2D material processing. Among 2D materials, hexagonal boron nitride (hBN) has a number of ou ...

American Chemical Society (ACS)2025

Study of backward Brillouin scattering in gas-filled anti-resonant fibers

Luc Thévenaz, Li Zhang, Malak Mohamed Hossameldeen Omar Mohamed Galal

Brillouin scattering in gas shows unmatched gain properties in hollow-core optical fibers filled at high pressure. Here, the gain characteristics are studied for two common gases, namely, N2 and CO2, which show distinct features and are compared to expecte ...

2023

Rayleigh-Based Distributed Optical Fiber Sensing Using Least Mean Square Similarity

Luc Thévenaz, Flavien Gyger, Zhisheng Yang, Li Zhang

Large frequency shift errors induced by cross-correlation are investigated in Rayleigh-based distributed sensing. A least mean square method is proposed to reduce those errors, thus increasing the reliability and extending the measurand range. ...

Optical Society of America2018

Distributed fiber temperature alarm system based on thermodynamic phase transition

Luc Thévenaz, Flavien Gyger, Li Zhang

A novel temperature sensing mechanism is proposed for the first time, based on thermodynamic phase transitions of CO2 in hollow-core fibers. A fast, sensitive and distributed fiber temperature alarm system is demonstrated using this concept. ...

Optica Publishing Group2020

Distributed Temperature Sensing Based on φ-OTDR Using Back-reflection-enhanced Fiber

Luc Thévenaz, Li Zhang, Malak Mohamed Hossameldeen Omar Mohamed Galal, Suneetha Sebastian

Distributed temperature sensing with 10 dB back-reflection-enhanced fiber is performed based on φ-OTDR. While the temperature sensitivity of such fibers is similar to that of standard single-mode fibers, a 3-times higher temperature resolution is observed. ...

Optical Society of America2021

Closed-loop technique based on gain balancing for real-time Brillouin optical time-domain analysis

Luc Thévenaz, Zhisheng Yang, Li Zhang, Ana Gabriela Correa Mena

A closed-loop servo control based on balancing the gain of two probing frequencies is proposed for real-time Brillouin optical time-domain analysis (BOTDA) without post-processing. With the most basic BOTDA hardware setup, the system can perform measuremen ...

2022

Minimizing distortion and enlarging group delay in Brillouin slow light systems by gain profile optimization

Luc Thévenaz, Marcelo Alfonso Soto Hernandez, Li Zhang

Optimal gain spectra minimizing distortion and enhancing delaying efficiency in linear slow light systems are predicted and experimentally validated by shaping the gain spectral profile in a Brillouin fiber amplifier. ...

Optical Society of America2014

Analysis and Reduction of Large Errors in Rayleigh-based Distributed Sensor

Luc Thévenaz, Marcelo Alfonso Soto Hernandez, Zhisheng Yang, Li Zhang

Commonly, the frequency shift of back-reflection spectra is the key parameter to measure quantitatively local temperature or strain changes in frequency-scanned Rayleigh-based distributed fiber sensors. Cross-correlation is the most common method to estima ...

IEEE Institute of Electrical and Electronics Engineers2019

[Erratum] Study of backward Brillouin scattering in gas-filled anti-resonant fibers (vol 8, 086104, 2023)

Luc Thévenaz, Li Zhang, Malak Mohamed Hossameldeen Omar Mohamed Galal

AIP Publishing2025

High spatial resolution distributed and dynamic strain sensing using direct detection

Luc Thévenaz, Zhisheng Yang, Li Zhang

A distributed dynamic strain sensing system based on frequency-scanned phase-sensitive optical time domain reflectometry is proposed and demonstrated. It demonstrates a record spatial resolution of 20 cm, compared with other direct-detection dynamic strain ...

Optica Publishing Group2021

Closed-loop technique using gain balance for fast Brillouin Optical Time-Domain Analysis

Luc Thévenaz, Zhisheng Yang, Li Zhang, Ana Gabriela Correa Mena

A closed-loop servo control based on the gain ratio of two probing frequencies is proposed for fast BOTDA, where the feedback is independent of probe and pump loss, making it robust in harsh environment. ...

Optica Publishing Group2022

Long-distance distributed pressure sensing based on frequency-scanned phase-sensitive optical time-domain reflectometry

Luc Thévenaz, Zhisheng Yang, Li Zhang

In this paper, a long-distance distributed pressure sensing system based on a special fiber and using frequency-scanned phase-sensitive optical time-domain reflectometry is proposed. The fiber shows high pressure sensitivity (159 MHz/bar) and low loss (3 d ...

2021

Distributed hydrostatic pressure measurement using phase-OTDR in a highly birefringent photonic crystal fibre

Luc Thévenaz, Kenny Hey Tow, Li Zhang

We demonstrate a distributed hydrostatic pressure measurement based on phase-sensitive optical time-domain reflectometry in a highly birefringent photonic crystal fibre with a 0.4 bar pressure resolution and a 10 cm spatial resolution. ...

Optical Society of America2018

Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition)

Françoise Gisou van der Goot Grunberg, Li Jin, Andreas Kern, Maurizio Molinari, Jun Ren, Wei Chen, Jian Zhang, Yi Sun, Ke Liu, Yang Sun, Wei Liu, Peng Wang, Fan Zhang, Jian Wang, Li Zhang, Giuseppe Russo, Hong Zhang, Liang Xu, Jun Li, Jian Yang, Chong Liu, Ke Li

Taylor & Francis Inc2016

Distributed hydrogen monitoring with phase-sensitive optical time-domain reflectometry

Luc Thévenaz, Li Zhang

We propose a distributed hydrogen sensing system based on ϕ-OTDR and a novel coating configuration with fiber adhesively bonding to palladium foils. An ultra-high sensitivedistributed hydrogen sensing with 5 cm spatial resolution is demonstrated ...

Optical Society of America2018

Finite Volume Effects in Water Nanodroplets: A Molecular Level Investigation

Sylvie Roke, Saranya Pullanchery Sankara Narayanan, Li Zhang

American Chemical Society (ACS)2025

Analytical prediction of the final error due to noise in a ϕ-OTDR system

Luc Thévenaz, Li Zhang, Malak Mohamed Hossameldeen Omar Mohamed Galal, Suneetha Sebastian, Yuting Yang

An analytical expression to estimate the uncertainty on the frequency shift in ϕ-OTDR systems is established and confirmed by actual data. ...

Optica Publishing Group2022

New Avenues in Optical Fiber Sensing Using Gas

Luc Thévenaz, Flavien Gyger, Marcelo Alfonso Soto Hernandez, Li Zhang, Malak Mohamed Hossameldeen Omar Mohamed Galal, Fan Yang, Yuting Yang

Gases turn out to be a very attractive medium for optical fiber sensing, showing highly flexible possibilities though widely unexploited so far. A new era opens for fiber sensing, exploiting the unprecedented potentialities of fluids. ...

Optica Publishing Group2023

Distributed Temperature Sensing Using Gas-filled Conjoined-tube Anti-resonant Fiber

Luc Thévenaz, Li Zhang, Malak Mohamed Hossameldeen Omar Mohamed Galal

Distributed temperature measurement is conducted for the first time in a gas-filled conjoined-tube hollow-core anti-resonant fiber (HC-CAF) at a pressure of 34.7 bar. A Brillouin gain of 0.08 m−1W−1 and a temperature sensitivity of 2 MHz/K are yielded. ...

Optica Publishing Group2022