Article
Optics
Alexandre Stathopulos, Stefan Skupin, Luc Berge
Summary: In this study, the influence of multi-color femtosecond laser pulses with different polarization states ionizing air or noble gases on emitted terahertz radiation was investigated. It was found that circular laser polarization is more efficient for a few harmonics, while linear polarization is favorable for more than six pump colors. Experiment and numerical simulations confirmed this property.
Article
Optics
SongPo Xu, MingQing Liu, Wei Quan, XiaoPeng Yi, ShiLin Hu, LiBin Zheng, ZhiQiang Wang, Meng Zhao, ShaoGang Yu, RenPing Sun, YanLan Wang, LinQiang Hua, XuanYang Lai, Wilhelm Becker, Jing Chen, XiaoJun Liu
Summary: S-matrix theory and the Born expansion, particularly the second-order term, provide an effective theory for understanding atomic and molecular processes in intense laser fields. The convergence problem of the Born series arises when dealing with long-range potentials such as the Coulomb potential. By conducting experiments and simulations on an argon atom subjected to a strong laser field, we demonstrate that the second-order term of the S-matrix expansion can accurately reproduce the observed phenomena, while the lowest-order term cannot.
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
Meng Han, Peipei Ge, Yiqi Fang, Yunquan Liu
Summary: This study systematically investigates the wavelength scaling of photoionization circular dichroism of electron ring currents. It reveals that the transition of circular dichroism and the spin polarization of photoelectrons in a few-photon ionization regime is caused by the interference and competition of intermediate states with different angular quantum numbers.
Article
Optics
A. A. Silaev, A. A. Romanov, N. V. Vvedenskii
Summary: The study proposes the use of optical laser pulses to generate Brunel harmonics (BHs) for high-resolution gas-biased coherent detection in terahertz and mid-infrared ranges. However, the strong linearly polarized laser pulse introduces broadband noise interference, which can be effectively suppressed by using elliptical polarization of the gating pulse.
Article
Optics
Guo-Li Wang, Hai-Xia Qi, Ya-Ning Li, Zhi-Hong Jiao, Song-Feng Zhao, Lei Zhang
Summary: It is discovered that polarization-controlled THz radiation, including circularly polarized radiation, can be generated using two-color circularly polarized laser fields. This study demonstrates that by adjusting the symmetry of the laser field, circularly polarized THz radiation can be achieved.
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS
(2022)
Article
Chemistry, Physical
Soumitra Das, Pramod Sharma
Summary: This study investigated the photoionisation of ethanol clusters at different laser wavelengths and intensities, exploring the mechanism of higher charge state formation. The results suggest that multiphoton ionisation and electron impact ionisation are the main processes involved, and their efficiency is influenced by the stability and intermolecular interactions of ethanol clusters.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
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
Multidisciplinary Sciences
Shaoxian Li, Ashutosh Sharma, Zsuzsanna Marton, Priyo S. Nugraha, Csaba Lombosi, Zoltan Ollmann, Istvan Marton, Peter Dombi, Janos Hebling, Jozsef A. Fulop
Summary: The confinement of single-cycle THz waveform-driven electron emission to one of the two half cycles from a solid surface emitter is demonstrated, with the active half cycle controlled by reversing the field polarity. This finding has significant implications for the development of THz-powered electron acceleration and manipulation devices, as well as other related technologies.
NATURE COMMUNICATIONS
(2023)
Article
Optics
Kareem J. Garriga Francis, Mervin Lim Pac Chong, E. Yiwen, X-C Zhang
Summary: We observed terahertz field-induced second harmonic (TFISH) generation by directly mixing an optical probe beam onto femtosecond plasma filaments. The TFISH signal is spatially separated from the laser-induced supercontinuum by impinging on the plasma at a noncollinear angle. The efficiency of converting the fundamental probe beam to its second harmonic beam is over 0.02%, representing a significant improvement compared to previous experiments. We also demonstrated the terahertz spectral buildup along the plasma filament and retrieved coherent terahertz signal measurements. This analysis method has the potential to measure local electric field strength inside the filament.
Article
Multidisciplinary Sciences
Chen Gong, Iwao Kawayama, Hironaru Murakami, Takahiro Teramoto, Masayoshi Tonouchi
Summary: Investigating the influences of infrared pump energy and air dispersion on terahertz generation in dual-color laser filament, and observing the linear shift of optimum dual-color laser relative phase with increasing pump energy due to intensity-induced refractive index change, enhances our understanding of the theoretical framework for a higher power THz source.
SCIENTIFIC REPORTS
(2021)
Article
Optics
Dasom Kim, Dai-Sik Kim, Geunchang Choi
Summary: We showed that a terahertz peak field amplitude below 0.01 MV/cm can initiate Zener tunneling in a semi-insulating GaAs. Furthermore, we observed a 60% decrease in transmission with an electric field strength of up to 46 MV/cm (maximum incident peak field of about 0.29 MV/cm) in the semi-insulating GaAs. These experimental results were achieved by exploiting nonlinear effects, such as Zener tunneling, impact ionization, and metal-insulator-metal tunneling in 5 nm metallic nanogaps on the GaAs, where a strong field was localized. The approach used in this study reduces the threshold incident electric field for nonlinear responses and opens pathways for ultra-thin high-speed electronic devices and ultrafast light pumps.
Article
Nanoscience & Nanotechnology
Kamalesh Jana, Emmanuel Okocha, Soren H. Moller, Yonghao Mi, Shawn Sederberg, Paul B. Corkum
Summary: This study demonstrates the use of structured light instead of structured materials to construct metasurfaces, transferring structure from light to transient currents in a semiconductor. The spatial light modulator is utilized to control the spatial structure of currents and resulting terahertz radiation with exceptional flexibility, enabling the metasurface to be reconfigured with unprecedented flexibility.
Article
Chemistry, Physical
Ting-Ting Fu, Fu-Ming Guo, Shu-Shan Zhou, Yue Qiao, Xin-Yu Wang, Ji-Gen Chen, Jun Wang, Yu-Jun Yang
Summary: Research on ultrafast dynamics and coherent light sources benefits from polarization control in high-order harmonic generation (HHG). By adjusting the amplitude of a Terahertz (THz) field in combination with an infrared (IR) laser, researchers are able to control the harmonic intensity and create near-circularly polarized attosecond pulses. Additionally, changing the carrier-envelope phase of the IR laser pulse allows modification of the ellipticity of the attosecond pulse.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Optics
Dejan B. Milosevic
Summary: It has been shown that utilizing extreme terahertz (THz) pulses to assist strong-laser-field ionization can significantly increase the electron yield and emitted photoelectron energy with a lower THz field intensity. The vector potential amplitude of the THz field, comparable to that of the laser field, is the key control parameter. Numerical results are obtained using the improved strong-field approximation, and a physical explanation is provided using quantum-orbit theory.
Article
Optics
Tim Suter, Alessandro Tomasino, Matteo Savoini, Sarah Houver, Roberto Morandotti, Steven l. Johnson, Elsa Abreu
Summary: We report the coherent generation and detection of terahertz (THz) pulses with a spectral bandwidth of 0.1-9 THz using a high repetition rate laser system. By combining a solid-state biased coherent detector with a spintronic emitter, we successfully measured the ultra-broadband THz frequency optical properties of bulk crystalline materials using time-domain spectroscopy.
Review
Optics
Yang Sun, Jiayang Wu, Mengxi Tan, Xingyuan Xu, Yang LI, Roberto Morandotti, Arnan Mitchell, David J. MOss
Summary: Optical microcombs are compact chip-scale devices that generate laser frequency combs, which have supported many technological advances in fundamental science and industrial applications. Their applications have rapidly progressed in the past decade, not only in traditional fields such as frequency synthesis, signal processing, and optical communications, but also in interdisciplinary fields including LiDAR, astronomical detection, neuromorphic computing, and quantum optics.
ADVANCES IN OPTICS AND PHOTONICS
(2023)
Review
Biophysics
Arash Aghigh, Stephane Bancelin, Maxime Rivard, Maxime Pinsard, Heide Ibrahim, Francois Legare
Summary: This article introduces the importance of Second Harmonic Generation (SHG) microscopy in various applications, describing its history, physical principles, and strengths and weaknesses in biomedical applications. It also provides an overview of SHG and advanced SHG imaging in neuroscience and microtubule imaging, discussing how these methods aid in understanding microtubule formation, structuration, and involvement in neuronal function. Finally, the article offers a perspective on the future of these methods and how technological advancements can make SHG microscopy a more widely adopted imaging technique.
BIOPHYSICAL REVIEWS
(2023)
Article
Chemistry, Multidisciplinary
Stefano A. Mezzasalma, Joscha Kruse, Stefan Merkens, Eneko Lopez, Andreas Seifert, Roberto Morandotti, Marek Grzelczak
Summary: This study presents a new self-oscillator model for illuminated colloidal systems. It predicts that the surface temperature of thermoplasmonic nanoparticles and the number density of their clusters jointly oscillate at frequencies ranging from infrasonic to acoustic values. Experimental results with gold nanorods strongly support the theory. These findings expand our understanding of self-oscillation phenomena and suggest the potential of colloidal systems as hosts for light-propelled machineries.
ADVANCED MATERIALS
(2023)
Article
Physics, Applied
A. Cutrona, M. Rowley, A. Bendahmane, V. Cecconi, L. Peters, L. Olivieri, B. E. Little, S. T. Chu, S. Stivala, R. Morandotti, D. J. Moss, J. S. Totero Gongora, M. Peccianti, A. Pasquazi
Summary: A detailed study on the free-running stability properties of single solitons is presented, which are the most suitable states for developing robust ultrafast and high repetition rate comb sources. The carrier frequency and repetition rate can be controlled by modulating the laser pump current and the cavity length, providing a path for active locking and long-term stabilization.
APPLIED PHYSICS LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Xingyuan Xu, Weiwei Han, Mengxi Tan, Yang Sun, Yang Li, Jiayang Wu, Roberto Morandotti, Arnan Mitchell, Kun Xu, David J. Moss
Summary: Optical neural networks (ONNs) based on wavelength-division multiplexing (WDM) techniques offer high bandwidth and analog architecture for enhanced computing power and energy efficiency. Integrated microcombs have been used to implement ONNs, with successful applications such as optical convolution accelerators for human image processing at 11 Tera operations per second. However, challenges and limitations of ONNs still need to be addressed for future applications.
IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS
(2023)
Article
Physics, Multidisciplinary
Mangaljit Singh, Muhammad Ashiq Fareed, Valeryia Birulia, Alexander Magunov, Alexei N. Grum-Grzhimailo, Philippe Lassonde, Antoine Laramee, Romain Marcelino, Ramin Ghahri Shirinabadi, Francois Legare, Tsuneyuki Ozaki, Vasily Strelkov
Summary: Studying the dynamics of dark autoionizing states is challenging due to their short lifetime, but high-order harmonic generation has emerged as a promising method. In this study, a new type of ultrafast resonance state resulting from the coupling between Rydberg and a dark autoionizing state dressed by a laser photon is demonstrated. This induced resonance can be leveraged to investigate the dynamics of a single dark autoionizing state and the transient changes in real states due to their overlap with laser-dressed states. Additionally, the generation of coherent ultrafast extreme ultraviolet light for advanced science applications is possible.
PHYSICAL REVIEW LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Luke Peters, Juan Sebastian Totero Gongora, Vittorio Cecconi, Luana Olivieri, Jacob Tunesi, Alessia Pasquazi, Marco Peccianti
Summary: Efficiency in terahertz (THz) wave generation is a subject of intense research. Currently, generation via quadratic crystals is the most common method due to its simplicity and practicality. This study demonstrates a new approach, using quantum interference (QI) in noncentrosymmetric crystals in conjunction with phase-matched quadratic generation, to generate THz waves. This approach not only explores a new physical setting but also achieves higher conversion efficiencies and control over THz components. It has significant implications for spectroscopy and imaging applications.
ADVANCED OPTICAL MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Luana Olivieri, Luke Peters, Vittorio Cecconi, Antonio Cutrona, Maxwell Rowley, Juan Sebastian Totero Gongora, Alessia Pasquazi, Marco Peccianti
Summary: Terahertz time-domain imaging aims to reconstruct the full electromagnetic morphology of an object. This method enables three-dimensional microscopy by implementing field-sensitive microvolumetry using time-resolved nonlinear ghost imaging. The technique can separate and discriminate information from different depths and planes, making it suitable for objects with sparse micrometric details.
Article
Engineering, Electrical & Electronic
Yang Sun, Jiayang Wu, Yang Li, Mengxi Tan, Xingyuan Xu, Sai Tak Chu, Brent E. Little, Roberto Morandotti, Arnan Mitchell, David J. Moss
Summary: Photonic RF transversal signal processors, implemented with photonic technologies, offer high-speed information processing with reduced size, power consumption, and complexity. Optical microcombs generated from compact micro-resonators are ideal sources for RF photonics. This study provides a detailed analysis of the processing accuracy of microcomb-based photonic RF transversal signal processors. Theoretical limitations, practical error sources, and the relative contributions of both are investigated, highlighting the potential for further error reduction through feedback control.
IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS
(2023)
Article
Chemistry, Multidisciplinary
Bennet Fischer, Mario Chemnitz, Yi Zhu, Nicolas Perron, Piotr Roztocki, Benjamin Maclellan, Luigi Di Lauro, A. Aadhi, Cristina Rimoldi, Tiago H. Falk, Roberto Morandotti
Summary: This study presents an implementation of neuromorphic wave computing using broadband frequency conversion in a single-mode fiber. The results show that through phase encoding and frequency selection and weighting, energy-efficient emulation of various digital neural networks is possible. The experiments demonstrate an enhancement in computational performance with increasing system nonlinearity. The findings also suggest that broadband frequency generation accessible on-chip and in-fiber may challenge traditional approaches to brain-inspired hardware design, leading to energy-efficient and scalable computing.
Article
Materials Science, Multidisciplinary
Tie-Jun Wang, Mehdi H. Ebrahim, Ivi Afxenti, Dionysis Adamou, Adetunmise C. Dada, Ruxin Li, Yuxin Leng, Jean-Claude Diels, Daniele Faccio, Arnaud Couairon, Carles Milian, Matteo Clerici
Summary: Cumulative effects play a crucial role in the applications of laser filaments, such as energy transfer and electric discharge control. Previous studies have mainly focused on low repetition rates (<10 kHz), but this study experimentally characterizes the nonlinear effects of short plasma filaments generated by moderate energy pulses (0.4 mJ per pulse) at repetition rates up to 100 kHz. The results show that with increasing repetition rate, there is a decrease in absorption, fluorescence emission, and breakdown voltage, along with an increase in peak intensity and third-harmonic-generation efficiency. These findings provide valuable insights for applications involving laser-induced air waveguides or electric discharge and lightning control.
ADVANCED PHOTONICS RESEARCH
(2023)
Article
Optics
Yang Li, Yang Sun, Jiayang Wu, Guanghui Ren, Bill Corcoran, Xingyuan Xu, Sai T. Chu, Brent. E. Little, Roberto Morandotti, Arnan Mitchell, David J. Moss
Summary: In this study, we experimentally demonstrate the capability of microcomb-based MWP signal processors to handle diverse input signal waveforms, and quantify the processing accuracy for different waveforms. Theoretical analysis reveals the factors contributing to the difference in processing accuracy among different input waveforms.
Proceedings Paper
Nanoscience & Nanotechnology
Van-Thuy Hoang, Bruno P. Chaves, Yassin Boussafa, Lynn Sader, Alexis Bougaud, Bennet Fischer, Mario Chemnitz, Piotr Roztocki, Benjamin MacLellan, Christian Reimer, Michael Kues, Alessia Pasquazi, Marco Peccianti, Sebastien Fevrier, Vincent Couderc, Brent E. Little, Sai T. Chu, David J. Moss, Jose Azana, Roberto Morandotti, Benjamin Wetzel
Summary: This article reviews recent research on advanced optical processing using integrated and fibered platforms. The study shows that machine learning in photonics systems can be used to generate custom optical wave-packets relevant for specific applications. The extension of this approach within multimode fibers is also discussed.
2023 IEEE PHOTONICS SOCIETY SUMMER TOPICALS MEETING SERIES, SUM
(2023)
Proceedings Paper
Nanoscience & Nanotechnology
Luigi Di Lauro, Imtiaz Alamgir, Stefania Sciara, Pavel Dmitriev, Celine Mazoukh, Hao Yu, Seyedeh Nazanin. Kamali, Riza Fazili, Aadhi A. Rahim, Bennet Fischer, Brent E. Little, Sai T. Chu, David J. Moss, Zhiming Wang, Roberto Morandotti
Summary: In this study, we develop novel, highly efficient, and secure smart technologies for telecom signal processing using on-chip photonic devices that support multimode interaction via four-wave mixing.
2023 IEEE PHOTONICS SOCIETY SUMMER TOPICALS MEETING SERIES, SUM
(2023)
