Article
Optics
Christian Brahms, John C. Travers
Summary: We demonstrate a bright, efficient, and compact source of tuneable deep ultraviolet (DUV) ultrafast laser pulses based on resonant dispersive wave emission in hollow capillary fiber.
Article
Optics
Jiafeng Lu, Jing Tian, Bertrand Poumellec, Enrique Garcia-Caurel, Razvigor Ossikovski, Xianglong Zeng, Matthieu Lancry
Summary: Chiral nanostructures in glass can exhibit polarization-selective optical properties, which can be controlled using femtosecond laser direct writing. A phenomenological model based on two-layers phase shifters has been proposed to explain laser-induced optical chirality in initially achiral materials. This model allows for optical rotation in silica glass with the highest value reported in glass to date, providing new opportunities for photonics applications.
LIGHT-SCIENCE & APPLICATIONS
(2023)
Article
Optics
M. Reduzzi, M. Pini, L. Mai, F. Cappenberg, L. Colaizzi, F. Vismarra, A. Crego, M. Lucchini, C. Brahms, J. C. Travers, R. Borrego-varillas, M. Nisoli
Summary: This article reports on the complete temporal characterization of ultrashort pulses generated by resonant dispersive wave emission in gas-filled hollow-capillary fibers. The energy of these pulses ranges from deep-ultraviolet to ultraviolet and they are continuously tunable. Temporal characterization of these ultrabroad pulses, which is particularly challenging in this spectral region, was achieved using an all-in-vacuum setup for self-diffraction frequency resolved optical gating (SD-FROG). Sub-3-fs pulses were measured, tunable from 250 nm to 350 nm, with a minimum pulse duration of 2.4 ± 0.1 fs.
Article
Optics
Junchi Zhang, W. R. Donaldson, Govind P. Agrawal
Summary: This study investigates the impact of the finite rise time of a spatiotemporal boundary inside a dispersive medium on the reflection and refraction of optical pulses. It is found that the frequency range over which reflection can occur decreases as the rise time increases. Additionally, total internal reflection can occur even for boundaries with long rise times, suggesting the possibility of realizing spatiotemporal waveguides through cross-phase modulation with pump pulses of relatively long rise and fall times.
Article
Optics
Louis Daniault, Zhao Cheng, Jaismeen Kaur, Jean-Francois Hergott, Fabrice Reau, Olivier Tcherbakoff, Nour Daher, Xavier Delen, Marc Hanna, Rodrigo Lopez-Martens
Summary: This study reports the nonlinear temporal compression of mJ energy pulses from a Ti:Sa chirped pulse amplifier system in a multipass cell filled with argon. The compressed pulses are brought down from 30 fs to 5.3 fs, corresponding to two optical cycles, with excellent spatial quality and homogeneity in the post-compressed beam. These results offer guidelines for optimizing compressed pulse quality and scaling multipass-cell-based post-compression down to the single-cycle regime.
Article
Physics, Multidisciplinary
Hannes Kempf, Philipp Sulzer, Andreas Liehl, Alfred Leitenstorfer, Ron Tenne
Summary: Measuring electric field waveforms beyond radio frequencies typically requires the challenging synthesis of gate pulses shorter than half of the field's oscillation period. In this study, the authors demonstrate an alternative approach by directly measuring the electric-field transient via a third-order nonlinear interaction without the need for high-energy laser pulses.
COMMUNICATIONS PHYSICS
(2023)
Article
Optics
Yunlong Mo, Wei Cao, Huiyao Xu, Kang Mi, Xuechun Sun, Qingbin Zhang, Peixiang Lu
Summary: This study shows that a thick crystal can achieve sufficient spectrum bandwidth response when the phase-matching wavelength is tuned outside of the spectral window of the measured pulse, enabling successful characterization of ultrashort laser pulses. The accuracy of the method was confirmed by comparing it with traditional pulse retrieval approaches.
Article
Chemistry, Multidisciplinary
Nikoleta Kotsina, Christian Brahms, Sebastian L. Jackson, John C. Travers, Dave Townsend
Summary: By exploiting the phenomenon of resonant dispersive wave emission, we have achieved time-resolved photoelectron imaging measurements with extremely short temporal resolution, advancing the current state of the art in ultrafast photoelectron spectroscopy. Our research findings can contribute to a better understanding of ultrafast photochemical reactions and provide a novel approach for future spectroscopic applications.
Article
Materials Science, Multidisciplinary
Migle Kuliesaite, Vygandas Jarutis, Jokubas Pimpe, Julius Vengelis
Summary: This paper investigates the generation of ultraviolet-visible light in a short photonic crystal fiber pumped by short pulses of 110 fs duration and 1028 nm wavelength, presenting a partially coherent nonlinear phenomenon occurring simultaneously.
RESULTS IN PHYSICS
(2021)
Article
Optics
Cheng Zhang, Tiandao Chen, Jinyu Pan, Zhiyuan Huang, Donghan Liu, Ding Wang, Fei Yu, Dakun Wu, Yu Zheng, Ruochen Yin, Xin Jiang, Meng Pang, Yuxin Leng, Ruxin Li
Summary: In this study, we demonstrate the first time-domain measurement of sub-microjoule, few-femtosecond ultraviolet dispersive-wave pulses generated in gas-filled hollow capillary fibers in an atmosphere environment. The measured pulse temporal profiles, obtained using a self-diffraction frequency-resolved optical gating setup, show pulse widths close to the Fourier-transform limits at 384 nm and 430 nm. The temporal width and shape of the measured dispersive-wave pulses are strongly influenced by the driving pulse energy and Ha' length. The obtained ultraviolet pulses with microjoule-level pulse energy, few-femtosecond pulse width, and broadband wavelength tunability are ready to be utilized in various applications.
Article
Multidisciplinary Sciences
Tommy Boilard, Real Vallee, Martin Bernier
Summary: We propose an efficient method to determine the effective refractive index of step-index optical fibers and infer their dispersion properties. The validity of the method is confirmed through the writing of fiber Bragg gratings and applied to different materials.
SCIENTIFIC REPORTS
(2022)
Article
Optics
Yitan Gao, Yabei Su, Siyuan Xu, Xiaoxian Zhu, Kun Zhao, Shaobo Fang, Jiangfeng Zhu, Zhiyi Wei
Summary: Femtosecond few-cycle pulses with annular shape are generated by propagating 40fs laser pulses through 6 solid thin plates in numerical simulations and experiments. The generation of such pulses relies on the conical emission caused by plasma effect, inducing negative dispersion leading to self-compression of the pulse and formation of an annular beam. By adjusting input pulse energy and the position of thin plates relative to laser focus, control over plasma density can be achieved, modifying the ratio between ionization and positive dispersion effects to regulate laser intensity and plasma density, thereby managing the negative dispersion experienced by the pulse during propagation.
Article
Optics
Francois Labaye, Valentin J. Wittwer, Marin Hamrouni, Norbert Modsching, Eric Cormier, Thomas Suedmeyer
Summary: A novel pumping scheme relying on cross polarization has been developed to overcome performance limitations commonly seen in standard collinear pumping schemes, leading to high-efficiency and high-power ultrafast bulk laser oscillators.
Article
Optics
Olivier Bernard, Andrea Kraxner, Assim Boukhayma, Jeff A. Squier, Christian Enz, Yves Bellouard
Summary: In the last two decades, ultrafast in-volume laser-based processing of transparent materials has become a key 3D-printing method. However, determining suitable laser process parameters for a given substrate is still a time-consuming task. This study introduces a method using in situ full-field third-harmonic generation (THG) microscopy to quickly identify the entire processing space and extract incubation laws governing the laser exposure process, enabling accelerated implementations of laser processes and closed-loop process control.
Article
Construction & Building Technology
Wenchao He, Wallace Wai-Lok Lai, Xin Sui, Antonios Giannopoulos
Summary: Detection of delamination in asphalt pavement using non-destructive ground penetrating radar (GPR) is valuable for maintenance and repair. However, limitations in GPR survey resolution and wave interferences make it challenging to characterize thin delamination layers. This paper proposes a new method using the GPR waveguide dispersion model in a wide-angle reflection and refraction (WARR) configuration to characterize delamination layers. The approach is validated through synthetic and laboratory experiments, showing sensitivity to air-filled and water-filled delamination, enabling the detection and identification of delamination layers in asphalt pavement structures.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Correction
Optics
P. Roth, Y. Chen, M. C. Gunendi, R. Beravat, N. N. Edavalath, M. H. Frosz, G. Ahmed, G. K. L. Wong, P. St. J. Russell
Summary: Recent work has identified an error in the dispersion relation of helical Bloch modes in a ring of capillaries. The error has been corrected, and a revised version of Fig. 2 is provided.
Article
Optics
Jie Luan, Philip St. J. Russell, David Novoa
Summary: We successfully achieved self-compression of near-UV pulses using numerical modeling of nonlinear pulse dynamics in the fiber. The experimental results demonstrate the significance of this technique for time-resolved studies in spectroscopy, chemistry, and materials science.
PHOTONICS RESEARCH
(2022)
Article
Multidisciplinary Sciences
Xinglin Zeng, Philip St J. Russell, Christian Wolff, Michael H. Frosz, Gordon K. L. Wong, Birgit Stiller
Summary: This study reports a light-driven nonreciprocal isolation system for optical vortex modes based on topology-selective stimulated Brillouin scattering (SBS) in chiral photonic crystal fiber. The experimental results show a vortex isolation of 22 decibels (dB), which is at the state of the art in fundamental mode isolators using SBS. This device may find applications in optical communications, fiber lasers, quantum information processing, and optical tweezers.
Article
Optics
Philip St. J. Russell, Yang Chen
Summary: This paper investigates the localization of light in disordered or periodically structured dielectric media, with a focus on coreless photonic crystal fiber (PCF) drawn in a chiral form. A novel analytical model for twisted coreless PCF is presented, which offers excellent agreement with numerical solutions of Maxwell's equations and significantly reduces computational time. The study reveals the existence of exponentially localized helical Bloch modes (HBMs) in chiral coupled sub-core lattices, opening up new possibilities for 2D localization of light.
LASER & PHOTONICS REVIEWS
(2023)
Article
Physics, Multidisciplinary
Allan S. Johnson, Daniel Perez-Salinas, Khalid M. Siddiqui, Sungwon Kim, Sungwook Choi, Klara Volckaert, Paulina E. Majchrzak, Soren Ulstrup, Naman Agarwal, Kent Hallman, Richard F. Haglund, Christian M. Guenther, Bastian Pfau, Stefan Eisebitt, Dirk Backes, Francesco Maccherozzi, Ann Fitzpatrick, Sarnjeet S. Dhesi, Pierluigi Gargiani, Manuel Valvidares, Nongnuch Artrith, Frank de Groot, Hyeongi Choi, Dogeun Jang, Abhishek Katoch, Soonnam Kwon, Sang Han Park, Hyunjung Kim, Simon E. Wall
Summary: Using time- and spectrally resolved coherent X-ray imaging, the researchers track the prototypical light-induced insulator-to-metal phase transition in vanadium dioxide on the nanoscale with femtosecond time resolution. They observe that the early-time dynamics are independent of the initial spatial heterogeneity and show a 200 fs switch to the metallic phase. Heterogeneous response emerges only after hundreds of picoseconds.
Article
Optics
Christian Brahms, John C. Travers
Summary: We demonstrate a bright, efficient, and compact source of tuneable deep ultraviolet (DUV) ultrafast laser pulses based on resonant dispersive wave emission in hollow capillary fiber.
Article
Physics, Applied
Francesco Tani, Jacob Lampen, Martin Butryn, Michael H. Frosz, Jie Jiang, Martin E. Fermann, Philip St. J. Russell
Summary: We integrate soliton dynamics in gas-filled hollow-core photonic crystal fibers with a cutting-edge fiber laser to create a turnkey system that can generate few-femtosecond pulses at an 8-MHz repetition rate, even at low pump energies. By utilizing soliton self-frequency shift in a second hydrogen-filled hollow-core fiber, we are able to efficiently produce pulses as short as 22 fs, continuously tunable from 1100 to 1474 nm.
PHYSICAL REVIEW APPLIED
(2022)
Article
Optics
Christian Brahms
Summary: Gas-filled hollow-core fibers are used to manipulate ultrafast laser pulses through nonlinear optical effects. The coupling efficiency is affected by self-focusing in gas-cell windows. The interplay of nonlinear reshaping and linear dispersion of the window depends on material, pulse duration, and wavelength, and longer-wavelength beams are more tolerant to high intensity in the window. The simulations provide a simple expression for the minimum distance between the window and the fiber entrance facet, which has implications for the design of hollow-core-fiber systems.
Article
Optics
Mohammed Sabbah, Federico Belli, Christian Brahms, Fei Yu, Jonathan Knight, John C. Travers
Summary: We investigate soliton self-compression and photoionization effects in an argon-filled antiresonant hollow-core photonic crystal fiber pumped with a commercial Yb:KGW laser. Before the onset of photoionization, we demonstrate selfcompression of our 220 fs pump laser to 13 fs in a single and compact stage. By using the plasma driven soliton selffrequency blueshift, we also demonstrate a tunable source from 1030 to similar to 700 nm. We fully characterize the compressed pulses using sum-frequency generation time-domain ptychography, experimentally revealing the full time-frequency plasma-soliton dynamics in hollow-core fiber for the first time.
Article
Optics
M. Reduzzi, M. Pini, L. Mai, F. Cappenberg, L. Colaizzi, F. Vismarra, A. Crego, M. Lucchini, C. Brahms, J. C. Travers, R. Borrego-varillas, M. Nisoli
Summary: This article reports on the complete temporal characterization of ultrashort pulses generated by resonant dispersive wave emission in gas-filled hollow-capillary fibers. The energy of these pulses ranges from deep-ultraviolet to ultraviolet and they are continuously tunable. Temporal characterization of these ultrabroad pulses, which is particularly challenging in this spectral region, was achieved using an all-in-vacuum setup for self-diffraction frequency resolved optical gating (SD-FROG). Sub-3-fs pulses were measured, tunable from 250 nm to 350 nm, with a minimum pulse duration of 2.4 ± 0.1 fs.
Article
Optics
Teodora Grigorova, Christian Brahms, Federico Belli, John C. Travers
Summary: We investigated the nonlinear optical pulse dynamics of ultrashort laser pulses in gas-filled hollow capillary fibers with different dispersion regimes achieved by adjusting the gas pressure. The results showed various soliton-plasma effects in the anomalous dispersion regime, pulse splitting and cross-phase modulation near the zero-dispersion wavelength, and the generation of a broad and flat supercontinuum in the normal dispersion regime. The experimental results in the latter regime were influenced by self-focusing and ionization effects, which altered the spatial and temporal shape of the pulse.
Article
Physics, Multidisciplinary
L. Genovese, M. Kellermeier, F. Mayet, K. Floettmann, G. K. L. Wong, M. H. Frosz, R. Assmann, P. St. J. Russell, F. Lemery
Summary: Emerging accelerator concepts are using high-frequency electromagnetic radiation to manipulate electron beams, which supports a variety of advanced applications. In this study, we propose a scheme using laser-driven large-core antiresonant optical fibers to manipulate the electron beams. We explore two general cases using different modes and demonstrate the potential for large energy modulations and the production of attosecond microbunches. These findings have wide applicability in high-charge pump-probe experiments, metrology, and accelerator science.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Chemistry, Multidisciplinary
Nikoleta Kotsina, Christian Brahms, Sebastian L. Jackson, John C. Travers, Dave Townsend
Summary: By exploiting the phenomenon of resonant dispersive wave emission, we have achieved time-resolved photoelectron imaging measurements with extremely short temporal resolution, advancing the current state of the art in ultrafast photoelectron spectroscopy. Our research findings can contribute to a better understanding of ultrafast photochemical reactions and provide a novel approach for future spectroscopic applications.
