Article
Optics
Amy L. Lytle, Eric Dyke, Julia Novella, Thomas Branch, Etienne Gagnon
Summary: Counter-propagating ultrafast pulses disrupt the phase of harmonic generation and can achieve quasi-phase matching. By comparing numerical simulations and experimental measurements of second harmonic generation (SHG), we find that a frequency-domain model that takes into account the broadband nature of ultrafast pulses better reproduces the observed features.
Article
Optics
A. Ovchinnikov, O. Chefonov, M. B. Agranat, A. Kudryavtsev, E. D. Mishina, A. A. Yurkevich
Summary: The study demonstrates that under the action of high-intensity terahertz pulses, an inhomogeneous distribution of charge carrier concentration is formed in silicon, which persists for several microseconds. This inhomogeneity is attributed to a sharp increase in the rate of filling the conduction band with free carriers in the subsurface input layer of the silicon wafer at field strengths above 15 MV/cm.
Article
Optics
Miguel Lopez-Ripa, Inigo J. Sola, Benjamin Alonso
Summary: This study presents a simple, compact, and ultra-stable spatiotemporal characterization technique based on bulk lateral shearing spectral interferometry using a birefringent uniaxial crystal, which allows for accurate measurement of ultrashort laser beams and retrieval of complex spatiotemporal structures of ultrafast optical vortices.
PHOTONICS RESEARCH
(2022)
Article
Optics
Wei-Chao Jiang, Mu-Xue Wang, Liang-You Peng, Joachim Burgdorfer
Summary: We investigate the features of stabilization in the angle-resolved spectra of photoelectrons when ground-state atomic hydrogen is exposed to an intense (around 10(18) W/cm(2)) linearly polarized ultrashort XUV pulse. In this scenario, atomic stabilization is attributed to the temporal destructive interference between wave packets released by the intense field at different time instants. By comparing numerical solutions of the time-dependent Schrodinger equation with a semi-analytical model, we are able to identify observed oscillations in momentum distribution and suppression of photoemission into the laser polarization direction as direct consequences of stabilization. The impact of nondipole corrections on angular distribution is also explored.
Article
Optics
Ana Cutuk, Marius Grossmann, Michael Jetter, Peter Michler
Summary: We introduce a new saturable absorber device principle with potential applications across a wide spectral range. By combining an active region membrane with a dielectric mirror, we create a membrane saturable absorber mirror (MESAM) that resembles a semiconductor saturable absorber mirror (SESAM) but without the limitations of a distributed Bragg reflector (DBR). In a red-emitting VECSEL, stable mode-locking was achieved using MESAM at a pump power of 4.25 W, resulting in a pulse duration of 3.06 ps at a repetition rate of 812 MHz. We compare the performance and pulses of both SESAM and MESAM in a z-shaped VECSEL cavity.
Article
Engineering, Electrical & Electronic
Dan Cheng, Yujun Feng, Meng Ding, Debasis Pal, Johan Nilsson
Summary: We demonstrate that random phase modulation using an intra-cavity electro-optic phase modulator does not inhibit the generation of ultrashort pulses in an erbium-doped fiber ring-laser. The laser is stable and self-starting, even when the phase modulator is driven with sufficiently fast and strong random sequences that render the laser cavity modeless. The lack of phase-sensitive elements in the cavity explains the insensitivity to random phase modulation.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Instruments & Instrumentation
Wanggen Sun, Kai Jiang, Wenjing Tang, Jian Su, Kang Chen, Qi Liu, Wei Xia
Summary: The mode-locked and harmonic mode-locked operations were achieved in an erbium-doped fiber laser using a high-quality germanene-polyvinyl alcohol film. The germanene film showed promising potential as a nonlinear photonic device for pulse lasers.
INFRARED PHYSICS & TECHNOLOGY
(2022)
Article
Optics
Zelin Hao, Wenwei Liu, Zhancheng Li, Zhi Li, Guangzhou Geng, Yanchun Wang, Hua Cheng, Hammad Ahmed, Xianzhong Chen, Junjie Li, Jianguo Tian, Shuqi Chen
Summary: Metasurfaces have shown great potential in optical wave manipulation but face challenges in multidimensional manipulation of harmonic waves generated by nonlinear metasurfaces. This study presents an efficient design strategy based on the hydrodynamic model of free electron dynamics, allowing for full complex-amplitude modulation of second harmonic generation. The proposed nonlinear metasurfaces demonstrate spin-selective SHG optical vortices with independent topological charges, opening up new possibilities for nonlinear metasurface applications in optical information and multifunctional integration.
LASER & PHOTONICS REVIEWS
(2021)
Article
Chemistry, Multidisciplinary
Binghao Yu, Qiang Hao, Cheng Tang, Kangwen Yang, Huaixi Chen, Wanguo Liang, Heping Zeng
Summary: In this paper, we demonstrate the creation of a femtosecond green laser using a MgO-doped periodically poled lithium niobate crystal pumped by a home-made Yb-doped MOPA laser system. The laser system produces stable laser pulses with high conversion efficiency and low intensity fluctuations, making it suitable for two-photon photopolymerization applications.
APPLIED SCIENCES-BASEL
(2022)
Article
Multidisciplinary Sciences
Maxim R. Shcherbakov, Haizhong Zhang, Michael Tripepi, Giovanni Sartorello, Noah Talisa, Abdallah AlShafey, Zhiyuan Fan, Justin Twardowski, Leonid A. Krivitsky, Arseniy Kuznetsov, Enam Chowdhury, Gennady Shvets
Summary: The researchers demonstrated highly efficient high harmonic generation on a nanoscale platform using a resonant gallium phosphide metasurface, which covers a wide range of photon energies while minimizing reabsorption and material damage. This study facilitates the exploration of the controllable transition between perturbative and non-perturbative regimes of light-matter interactions at the nanoscale.
NATURE COMMUNICATIONS
(2021)
Article
Optics
Shin Nakamura, Masahiro Sato, Takashi Fujii, Akiko Kumada, Yuji Oishi
Summary: The paper introduces a method for electric field measurement based on second-harmonic generation, proposing a new approach to calibrate and restore the electric field distribution by changing the focusing spot position.
Article
Chemistry, Multidisciplinary
Heming Xia, Xinyu Chen, Song Luo, Feng Qin, Alexander Idelevich, Saptarshi Ghosh, Toshiya Ideue, Yoshihiro Iwasa, Alla Zak, Reshef Tenne, Zhanghai Chen, Wei-Tao Liu, Shiwei Wu
Summary: This study reports an optical SHG study on multiwalled WS2 nanotubes at the single-tube level, revealing multiple structural domains within a single nanotube and observing different chirality within the same tube. Additionally, excitonic states of individual WS2 nanotubes were observed using SHG excitation spectroscopy, overcoming challenges posed by the material's indirect band gap.
Article
Optics
Xiaohui Ma, Shaoqing Liu, Wenwen Dai, Wu Chen, Liang Tong, Shanshan Ye, Ziqi Zheng, Yangyang Wang, Yong Zhou, Wei Zhang, Wentan Fang, Xiaolin Chen, Rui Wang, Ronghua Yu, Meisong Liao, Weiqing Gao
Summary: TiCN serves as a saturable absorber in a thulium-doped fiber laser, achieving harmonic mode-locking and generating ultrashort pulses with high repetition rates. Multiple harmonics are observed in the laser output.
OPTICS AND LASER TECHNOLOGY
(2022)
Article
Physics, Applied
Li-Hong Hong, Bao-Qin Chen, Chen-Yang Hu, Zhi-Yuan Li
Summary: Researchers have developed a theoretical approach called ST-BNCWT to evaluate the spatial and temporal evolution behaviors of femtosecond laser pulse second harmonic generation in a nonlinear medium. By analyzing the transmission characteristics of ultrashort laser pulses, they have revealed variations in key physical quantities.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Multidisciplinary Sciences
Mingzhou Li, Lihong Hong, Zhi-Yuan Li
Summary: We report a new type of ultrabroadband laser source with high pulse energy, which has attracted much attention in the fields of physics, chemistry, biology, material science, and other disciplines.
Article
Optics
Jan Tross, Shashank Pathak, Adam Summers, Dimitrios Rompotis, Benjamin Erk, Christopher Passow, Bastian Manschwetus, Rebecca Boll, Patrik Grychtol, Sadia Bari, Vinod Kumarappan, Anh-Thu Le, Cheng Jin, Carlos Trallero, Daniel Rolles
Summary: We present the results of an experiment investigating the generation of high-order harmonics through XUV-assisted high-order harmonic generation. Our findings demonstrate that the overlap of XUV and NIR pulses enhances the harmonic yield, while the XUV preceding the NIR pulse decreases the HHG yield.
Article
Physics, Multidisciplinary
Xiaochun Gong, Wenyu Jiang, Jihong Tong, Junjie Qiang, Peifen Lu, Hongcheng Ni, Robert Lucchese, Kiyoshi Ueda, Jian Wu
Summary: This study investigates the molecular-frame photoionization time delay near the shape resonance of the NO molecule using an attosecond interferometer. A 150 attosecond difference in the time delay between photoemission from the N/O end is observed. Quantum scattering theoretical simulations reproduce the experimental findings and demonstrate that the asymmetric time delay originates from the interference between resonant and nonresonant photoionization pathways.
Article
Chemistry, Physical
Kirk A. Larsen, Roger Y. Y. Bello, Robert R. Lucchese, C. William McCurdy, Daniel S. S. Slaughter, Thorsten Weber
Summary: We investigate the non-dissociative photoionization dynamics of neutral O-2 molecules using experimental and theoretical energy- and angle-resolved methods. By detecting photoelectrons and O-2(+) cations produced from one-color, two-photon ionization in coincidence, we find that the involved superposition of two intermediate electronic states dominates the process. The observed agreement between measured and calculated photoelectron angular distributions suggests that wavepacket motion on near-resonantly populated intermediate states does not significantly affect the two-photon ionization dynamics.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Physics, Multidisciplinary
Jennifer Joseph, Fabian Holzmeier, David Bresteau, Thierry Ruchon, Jean-Christophe Houver, Robert R. Lucchese, Danielle Dowek
Summary: We present experimental results for XUV-IR two-photon ionization of Ar, Ne, NO, and O-2 using attosecond pulse trains and synchronized IR pulses. The experiments provide temporally resolved photoelectron angular distributions and electron-ion kinetic energy correlation diagrams for different ionization processes. The results contribute to a better understanding of the ionization dynamics in these systems.
EUROPEAN PHYSICAL JOURNAL-SPECIAL TOPICS
(2023)
Article
Optics
Xiangyu Tang, Baochang Li, Kan Wang, Zhiming Yin, Chi Zhang, Zhong Guan, Bincheng Wang, C. D. Lin, Cheng Jin
Summary: We studied the role of the Porras factor (or laser focusing effect) in macroscopic high-order harmonic generation (HHG) driven by a focused broadband few-cycle laser beam. Our analysis revealed that the phase mismatch, caused by the induced-dipole phase, varies with the Porras factor, particularly in low gas pressure conditions. However, in highly ionized mediums with high gas pressure, the nonlinear propagation is dominated by plasma effects, mitigating the focusing effect and resulting in poor phase matching of HHG regardless of the Porras factor. These findings can guide experimentalists in optimizing conditions for HHG using ultrashort laser pulses.
Article
Physics, Multidisciplinary
Antoine Camper, Amelie Ferre, Valerie Blanchet, Dominique Descamps, Nan Lin, Stephane Petit, Robert Lucchese, Pascal Salieres, Thierry Ruchon, Yann Mairesse
Summary: By resolving the emission from two families of electronic quantum paths, this study avoids the need for advanced theoretical modeling and provides insights into attosecond electronic and vibrational dynamics. The quantum-path resolved spectroscopy opens up prospects for investigating ultrafast ionic dynamics, including charge migration.
PHYSICAL REVIEW LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Andrew J. Howard, Mathew Britton, Zachary L. Streeter, Chuan Cheng, Ruaridh Forbes, Joshua L. Reynolds, Felix Allum, Gregory A. McCracken, Ian Gabalski, Robert R. Lucchese, C. William McCurdy, Thomas Weinacht, Philip H. Bucksbaum
Summary: Filming atomic motion within molecules is an active pursuit of molecular physics and quantum chemistry, and laser-induced Coulomb Explosion Imaging (CEI) is a promising method. However, the rapid motion during ionization distorts the CEI results. Our study on water revealed the rapid slingshot motion that enhances ionization and distorts CEI results, providing insights into the geometry and mechanism of this enhancement, which can inform CEI experiments in other polyatomic molecules.
COMMUNICATIONS CHEMISTRY
(2023)
Article
Chemistry, Physical
W. Iskandar, T. N. Rescigno, A. E. Orel, T. Severt, K. A. Larsen, Z. L. Streeter, B. Jochim, B. Griffin, D. Call, V. Davis, C. W. Mccurdy, R. R. Lucchese, J. B. Williams, I. Ben-Itzhak, D. S. Slaughter, Th. Weber
Summary: This study investigates the relaxation dynamics of deuterated water molecules after direct photo-double ionization at 61 eV. It focuses on the rare D+ + O+ + D reaction channel where sequential fragmentation mechanisms dominate. The state-selective formation and breakup of transient OD+ are traced, and the most likely dissociation path, involving a combination of spin-orbit and non-adiabatic charge transfer transitions, is determined. The multi-step transition probability of the intermediate fragment ion is directly evaluated, reproducing the general trends of multi-state relative transition rates towards three-body fragmentation channels.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Physics, Multidisciplinary
Kan Wang, Yong Fu, Baochang Li, Xiangyu Tang, Bincheng Wang, Zhong Guan, C. D. Lin, Cheng Jin
Summary: In this study, we propose a method to retrieve an isolated attosecond pulse (IAP) in the time domain through the modulation of high-harmonic generation (HHG) spectra, using a time-delayed intense few-cycle infrared or mid-infrared laser. The retrieval algorithm is derived based on the strong-field approximation and a quantitative rescattering model. We demonstrate that both narrowband extreme ultraviolet (XUV) pulses and broadband soft x-ray (SXR) pulses can be characterized accurately using the HHG streaking spectra.
NEW JOURNAL OF PHYSICS
(2023)
Article
Optics
Zhiming Yin, Xiangyu Tang, Xuhong Li, Beiyu Wang, Jiaxin Han, C. D. Lin, Cheng Jin
Summary: Experimental simulations show that high-order harmonic generation from a long intense femtosecond laser can produce multiple shorter attosecond sub-bursts within each half optical cycle, which is different from the well-known attosecond pulse trains. The duration of each sub-burst scales approximately with the driving laser wavelength, and their origin is attributed to the interference of quantum orbits from the first two returns of the recombining electron. These sub-bursts can be phase matched and observed experimentally under specific laser focusing conditions and gas cell positioning.
Article
Optics
C. H. Yuen, P. Modak, Yan Song, Song-Feng Zhao, C. D. Lin
Summary: A density matrix approach for sequential double ionization of molecules has been developed and extended to the O2 system. The model shows good agreement with previous experiments on the kinetic energy release spectrum of O+ + O+. The low computational cost of the model allows for exploration of ionization and dissociation dynamics as well as laser effects on the spectrum.
Article
Optics
Ashley P. Fidler, Yen-Cheng Lin, James D. Gaynor, C. William McCurdy, Stephen R. Leone, Robert R. Lucchese, Daniel M. Neumark
Summary: This study investigates the dynamics of excited Rydberg states of CO2 molecule using attosecond extreme ultraviolet (XUV) four-wave mixing (FWM) spectroscopy, and observes emission signals from specific Rydberg series with consistent lifetimes. The calculated oscillator strengths confirm that the nonlinear spectra are dominated by specific excitation and emission pathways. The results demonstrate that nonlinear spectroscopic techniques are versatile tools for measuring ultrafast dynamics in polyatomic systems and accessing difficult-to-probe dynamics.
Article
Optics
C. H. Yuen, C. D. Lin
Summary: This study develops a simple model based on density-matrix approach to describe the sequential double ionization of molecules. The model can predict important information about molecular dynamics and shows good agreement with experimental results. This theoretical development opens up new opportunities for studying molecular dynamics using infrared laser pulses.
Article
Optics
Changzhi Jiang, Haoran Jiang, Yanbo Chen, Baochang Li, C. D. Lin, Cheng Jin
Summary: In this paper, a method using genetic algorithm is proposed to retrieve the alignment distribution of CO2 molecules from HHG spectra. The retrieval method is based on the quantitative rescattering model and considers the uncertainty and multiple orbital contribution. The results show that the alignment distribution can be more accurately retrieved using the minima in the HHG spectra driven by a long-wavelength laser.
Article
Optics
Xi Zhao, Siqi Li, Taran Driver, Van-Hung Hoang, Anh-Thu Le, James P. Cryan, Agostino Marinelli, C. D. Lin
Summary: Most traditional attosecond pulse retrieval algorithms cannot be used for attosecond pulses generated from free-electron x-ray lasers. However, using a circularly polarized infrared laser, a modified retrieval algorithm has been successfully applied to characterize single-shot attosecond pulses in recent experiments.
