A5018120667- Laser-Matter Interactions and Applications
- Terahertz technology and applications
- Spectroscopy and Laser Applications
- Spectroscopy and Quantum Chemical Studies
- Molecular Spectroscopy and Structure
- Advanced Fiber Laser Technologies
- Molecular spectroscopy and chirality
- Strong Light-Matter Interactions
- Fullerene Chemistry and Applications
- Photonic and Optical Devices
- Laser Design and Applications
- Mass Spectrometry Techniques and Applications
- Thermal Radiation and Cooling Technologies
- Quantum chaos and dynamical systems
- Mechanical and Optical Resonators
- Photonic Crystal and Fiber Optics
- Advanced Chemical Physics Studies
- Graphene research and applications
- Laser Material Processing Techniques
- Molecular Junctions and Nanostructures
- Laser-induced spectroscopy and plasma
- Analytical Chemistry and Sensors
- Laser Applications in Dentistry and Medicine
- Plasmonic and Surface Plasmon Research
- Gyrotron and Vacuum Electronics Research
Tel Aviv University
2014-2024
Massachusetts Institute of Technology
1993-2014
Weizmann Institute of Science
2005-2012
University of California, Santa Barbara
2000
Vassar College
1996
Intense single-cycle THz pulses resonantly interacting with molecular rotations are shown to induce field-free orientation and alignment under ambient conditions. We calculate measure the degree of both induced by field in an OCS gas sample, correlate between two observables. The data presents first observation THz-induced phase.
Abstract Spectroscopy aims at extracting information about matter through its interaction with light. However, when performed on gas and liquid phases as well solid lacking long‐range order, the extracted spectroscopic features are in fact averaged over molecular isotropic angular distributions. The reason is that light–matter processes depend angle between transitional dipole polarization of light interacting it. This understanding gave birth to constantly expanding field “laser‐induced...
Abstract The past two decades have witnessed an ever-growing number of emerging applications that utilize terahertz (THz) waves, ranging from advanced biomedical imaging, through novel security applications, fast wireless communications, and new abilities to study control matter in all its phases. development deployment these technologies is however held back, due a substantial lack simple methods for efficient generation, detection manipulation THz waves. Recently it was shown uniform...
Ultrafast two-dimensional spectroscopy utilizes correlated multiple light-matter interactions for retrieving dynamic features that may otherwise be hidden under the linear spectrum. Its extension to terahertz regime of electromagnetic spectrum, where a rich variety material degrees freedom reside, remains an experimental challenge. Here we report ultrafast gas-phase molecular rotors at room temperature. Using time-delayed pulse pairs, observe photon echoes and other nonlinear signals...
We introduce a new scheme for controlling the sense of molecular rotation. By varying polarization and delay between two ultrashort laser pulses, we induce unidirectional rotation, thereby forcing molecules to rotate clockwise/counterclockwise under field-free conditions. show that unidirectionally rotating are confined plane defined by vectors which leads permanent anisotropy in angular distribution. The latter may be useful collisional cross-sections optical kinetic processes gases....
The interaction of carbonyl sulfide dipolar gas molecules with two time-delayed, single-cycle THz pulses is shown both experimentally and theoretically to induce two-quantum rotational coherences that are significantly enhanced respect those induced by one pulse, depending on the relative delay pulses. underlying phenomenon quite general in it can occur even after a single pulse if more than molecular species present, since free induction decay emitted (demonstrated here atmospheric water...
Abstract Several years ago, strong coupling between electronic molecular transitions and photonic structures was shown to modify the landscape of molecules affect their chemical behavior. Since then, this concept has evolved into a new field known as polaritonic chemistry. An important ingredient in progress demonstration with intra-molecular vibrations, which enabled modification processes occurring at ground-state. Here we demonstrate collective, inter-molecular vibrations organic...
We experimentally demonstrate field-free, spin-selective alignment of ortho- and para molecular spin isomers at room temperature. By means two nonresonant, strong, properly delayed femtosecond pulses within a four wave mixing arrangement, we observed selective for homonuclear diatomics composed $1/2$ ($^{15}\mathrm{N}$) or $1$ ($^{14}\mathrm{N}$) atoms. The achieved control the isomers' angular distribution rotational excitation may find applications to analysis, enrichment, actual physical...
We experimentally demonstrate isotope-selective alignment in a mixture of $^{14}\mathrm{N}_{2}$, $^{15}\mathrm{N}_{2}$ isotopes. Following strong ultrashort laser pulse rotational excitation, the angular distributions isotopes gradually become different due to mismatch their moments inertia. At predetermined times, desired isotope attains an aligned state while other component is antialigned, facilitating further selective manipulations by polarized light. By properly timed second pulse,...
We experimentally study the optical- and terahertz- induced rotational dynamics of asymmetric molecules in gas phase. Terahertz optical fields are identified as two distinct control handles over molecules, they couple to degrees freedom via molecular- dipole polarizability selectively. The distinction between those is highlighted by different types quantum revivals observed long duration (>100ps) field-free evolution. experimental results excellent agreement with Random Phase Wave Function...
Biofabrication has proved to be a versatile and valuable tool for tissue engineering cancer research in order mimic different tumor microenvironments. In the present study, four cell lines, including two melanoma Mel Im Wei, breast MDA-MB-231 MCF-7, were tested combination with hydrogels. The hydrogels composite ink consisting of alginate, hyaluronic acid gelatine (Alg/HA/Gel), pre-crosslinked oxidized alginate (ADA-GEL), methyl cellulose (Meth-Alg) acrylated (HAA). Rheological analysis...
We report optimization of a stretched-pulse erbium-doped fiber laser for second-harmonic generation and the evaluation several nonlinear crystals this application. With compressed fundamental pulse energies 2.7 nJ at 31.8 MHz, we achieved 10% conversion efficiency 86-fs, 771-nm pulses with 270 pJ. Frequency-resolved optical gating was used to analyze both frequencydoubled pulses.
We study the dynamics of rotational echoes in gas phase molecular ensembles and their dependence on delay intensity excitation pulses. explore unique alignment that arise from multilevel nature rotors impose severe difficulties utilizing echo responses for spectroscopy. show experimentally theoretically judicious control both second pulse enables "rotational spectroscopy." The proposed methodology paves way to spectroscopy high-density samples.
We study and demonstrate the rephasing property of echo response in a multilevel rotational system iodomethane via long time-resolved optical birefringence measurements. The strong centrifugal distortion is utilized as dephasing mechanism imprinted on signal shown to rephase throughout its evolution. dependence amplitude driving pulses' intensities theoretically experimentally explored. analogy Hahn's spin echoes discussed, quantum-mechanical version track runners provided for case system.
The decay of field-free rotational dynamics is experimentally studied by two complementary methods: laser-induced molecular alignment and terahertz-field-induced orientation. A comparison between the rates different species at various gas pressures reveals that oriented ensembles faster than aligned ensembles. discrepancy in attributed to coherent radiation emitted transiently absent from molecules. experimental results reveal dramatic contribution radiative emission observed underline a...
Vibrational strong coupling is a phenomenon in which vibrational transition material placed inside photonic structure hybridized with its optical modes to form composite light–matter excitations known as vibro-polaritons. Here we demonstrate new concept of coupling: show that monolithic crystal, made resonant material, can exhibit between the confined and terahertz same material. We study this system both experimentally numerically characterize dispersion for various sample thicknesses...
A planar Fabry-Perot cavity with intermirror spacing of
The initial, ultrafast scattering of optically excited carriers in M3C60 for M=K, Rb is investigated by femtosecond pump–probe measurements. An initial fast response (τ≊0.2 ps) similar magnitude both Rb3C60 and K3C60 observed, while τ undoped C60 more than an order longer. These results are discussed terms the molecular character bandlike M3C60.
Intense terahertz-frequency pulses induce coherent rotational dynamics and orientation of polar molecular ensembles. Exact numerical methods for at room temperature are computationally not feasible the vast majority rotors: asymmetric top molecules ambient temperatures. We exemplify use random phase wave functions (RPWFs) by calculating terahertz-induced sulfur dioxide temperatures high-field strengths show that RPWF method gains efficiency with increase in terahertz-field strengths. The...
We demonstrate selective control over rotational motion of small, linear molecules. By means sequential excitation the by ultrashort pulses, we first prepare transiently aligned molecules with periodically revived angular distribution. Upon further, properly timed excitation, energy can be increased or decreased, depending on exact timing second pulse. show how this approach applied for a single component in molecular mixture. discuss selectivity context isotopes (14N2, 15N2), where...
We demonstrate and explore an all-optical technique for direct monitoring of the orientation dynamics in gas-phase molecular ensembles. The termed "MOISH" utilizes transiently lifted inversion symmetry polar gas media provides a sensitive spatially localized probing second-harmonic generation signal that is directly correlated with gas. Our experimental results reveal selective electronic nuclear dynamical contributions to overall nonlinear optical decipher them apart using "reporter gas"...
We report the femtosecond impulsive excitation of coherent phonons in alkali metal-doped fullerenes. These excitations appear as small oscillations reflectivity (ΔR/R∼10−7) produced by pump an optical pump-probe experiment. The observed include previously unobserved highly damped modes near 150 cm−1 well long-lived Ag(1) 490 cm−1.