A5039238470- Cold Atom Physics and Bose-Einstein Condensates
- Laser-Matter Interactions and Applications
- Orbital Angular Momentum in Optics
- Quantum Electrodynamics and Casimir Effect
- Quantum, superfluid, helium dynamics
- Quantum Information and Cryptography
- Quantum Mechanics and Applications
- Mechanical and Optical Resonators
- Laser Design and Applications
- Advanced Fiber Laser Technologies
- Atomic and Subatomic Physics Research
- Spectroscopy and Quantum Chemical Studies
- Atomic and Molecular Physics
- Strong Light-Matter Interactions
- High-pressure geophysics and materials
- Particle Accelerators and Free-Electron Lasers
- Physics of Superconductivity and Magnetism
- Cryospheric studies and observations
- Quantum optics and atomic interactions
- Catalytic C–H Functionalization Methods
- Lanthanide and Transition Metal Complexes
- Magnetic properties of thin films
- Synthesis of Indole Derivatives
- Plasmonic and Surface Plasmon Research
- Spectroscopy and Laser Applications
Ulsan National Institute of Science and Technology
2012-2024
Fritz Haber Institute of the Max Planck Society
2008-2012
Seoul National University
2000-2009
Harvard University
2003
Quantum reflection allows an atom or molecule to be reflected from a solid before it reaches the region where would encounter repulsive potential of surface. We observed nondestructive scattering helium dimer (He(2)), which has binding energy 10(-7) electron volt, grating. scattered beam containing as well atomic and larger clusters, but could differentiate by its diffraction angle. Helium dimers are quantum tens nanometers above surface, surface-induced forces too weak dissociate fragile bond.
A cylindrical molecular lens is formed by focusing a nanosecond IR laser pulse. Trajectories of CS2 beam deflected the are traced using velocity map imaging technique. The characteristic parameters including focal length, minimum width, and distance to minimum-width position determined. intensity dependence in good agreement with theoretical predictions. Exciting possibilities for optics new type optical chromatography opened up.
We observe high-resolution diffraction patterns of a thermal-energy helium atom beam reflected from microstructured surface grating at grazing incidence. The consists $10\text{\ensuremath{-}}\ensuremath{\mu}\mathrm{m}$-wide Cr strips patterned on quartz substrate and has periodicity $20\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{m}$. Fully resolved peaks up to the seventh order are observed angles $20\phantom{\rule{0.3em}{0ex}}\mathrm{mrad}$. With changes in de Broglie wavelength or...
We report coherent reflection of thermal He atom beams from various microscopically rough surfaces at grazing incidence. For a sufficiently small normal component k(z) the incident wave vector probability is found to be function only. This behavior explained by quantum attractive branch Casimir-van der Waals interaction potential. larger values overall decreases rapidly and also depend on parallel k(x) vector. The material specific dependence for this classic repulsive potential discussed in...
Annulative π-extension chemistry provides a concise synthetic route to polycyclic arenes. Herein, we disclose nondirected annulation approach of unactivated simple The palladium-catalyzed 2-fold C-H arylation event facilitates tandem C-C linkage relays furnish fully benzenoid triphenylene frameworks using cyclic diaryliodonium salts. inseparable regioisomeric mixture 1- and 2-methyltriphenylenes is identified by the combined analysis ion mobility-mass spectrometry, gas-phase infrared...
A molecular lens of the nonresonant dipole force formed by focusing a nanosecond IR laser pulse has been applied to benzene and CS2 beams. Using velocity map imaging technique for ray tracing, characteristic parameters including focal length (f ), minimum beam width (W), distance position (D) were determined. The intensity dependence observed was in good agreement with theoretical predictions. W independent peak (I0), whereas f D varied linearly 1/I0. differences between species well...
In molecule optics, a matter wave of molecules is manipulated by molecule-optical component made out external, typically radiative, fields. The index refraction, n, for nonresonant IR laser pulse focused onto molecular beam can be obtained from the energy conservation and properties molecules. Experimentally measured values n benzene nitric oxide agreed well with calculated values. Since depends on as those field, prism composed field separate multi-component into several components...
We demonstrate one-dimensional (1D) focusing of a thermal helium atom beam by quantum reflection from cylindrical concave quartz mirror at near-grazing incidence. The smallest width the focus achieved is 1.8 μm, essentially limited spherical aberration. various effects that contribute to finite focal have been investigated. propose apply two elliptical mirrors in Kirkpatrick–Baez arrangement for two-dimensional (2D) beam, paving way microprobe.
We report on the observation of emerging beam resonances, well known as Rayleigh-Wood anomalies and threshold resonances in photon electron diffraction, respectively, an atom-optical diffraction experiment. Diffraction He atom beams reflected from a blazed ruled grating at grazing incidence has been investigated. The total reflectivity intensities diffracted reveal Rayleigh angles incidence, i.e., when another emerges parallel to surface. observed are discussed terms classical wave-optical...
We report on the non-destructive scattering and diffraction of He, He2 He3 from a plane ruled reflection grating. At grazing incidence normal component particle’s wave-vector is sufficiently small to allow for quantum at attractive Casimir–van der Waals particle–surface interaction potential. Quantum occurs tens nanometres in front surface, before dimers trimers reach region where surface-induced forces would inevitably cause breakup fragile bonds. The reflected particles are identified via...
Researchers observed universal diffraction of He, He 2 , and D quantum-reflected tens nanometers above a ruled grating.
We produce a cool pulsed supersonic molecular beam of CaF radicals essentially without recourse to pumping. The are generated by laser ablating solid precursor target in small ablation cell volume about 0.01 cm3. is ablated through 750 μm orifice Nd:YAG laser. plume supersonically expands into vacuum chamber and cools the initially hot molecules seeded it. enhance character expansion feeding 10 Torr He, Ar, or Xe carrier gas. probed time-dependent absorption spectroscopy. With carrier, 1012...
We report on reflection and diffraction of beams He D_{2} from square-wave gratings a 400-μm period strip widths ranging 10 to 200 μm at grazing-incidence conditions. In each case we observe fully resolved matter-wave patterns including the specular diffracted up second order. With decreasing width, observed efficiencies exhibit transformation known regime quantum grating strips edge half-plane array. The latter is described by single-parameter model developed previously describe phenomena...
The properties of molecule-optical elements such as lenses or prisms based on the interaction molecules with optical fields depend in a crucial way molecular quantum state and its alignment created by field. Herein, we consider effects state-dependent estimating dipole force acting and, to this end, introduce an effective polarizability which takes proper account is directly related alignment-dependent force. We illustrate significance including trajectory study that compares previously used...
A simple method to control molecular translation with a chemical reaction is demonstrated. Slow NO molecules have been produced by partially canceling the beam velocity of 2 recoil photofragment. The were photodissociated using UV laser pulse polarized parallel beam. spatial profiles showed two peaks corresponding decelerated and accelerated molecules, in agreement theoretical prediction. significant portion stayed around initial dissociation positions even several hundred nanoseconds after...
We report on emerging beam resonances appearing in diffraction patterns of a helium atom reflected at grazing incidence from grating. The plane ruled grating is mounted an out-of-plane configuration. present the measured angular as function atom's energy change along normal. This presentation allows us to readily trace back peak positions and widths geometry In patterns, interference effect due found progress side by with new beam.
We report on the rotational-state-dependent, transverse acceleration of CS_{2} molecules affected by pulsed optical standing waves. The steep gradient wave potential imparts far stronger dipole forces than propagating pulses do. Moreover, large changes in velocities (i.e., up to 80 m/s) obtained with waves are well reproduced numerical simulations using effective polarizability that depends molecular rotational states. Our analysis based rotational-state-dependent can therefore serve as a...
Molecular beams of He and D2 are scattered from a ruled diffraction grating in conical-mount geometry under grazing-incidence conditions. Fully resolved patterns as function detection angle recorded for different azimuth angles two kinetic energies the particle beams. Variations peak widths traced back to velocity spreads determined by time-of-flight measurements. A comprehensive analysis intensities confirms universal diffraction, that is, identical de Broglie wavelengths, relative same....
The optical dipole force acting on molecules is enhanced by decreasing the rotational temperature of molecule and aligning molecular axis with a linearly polarized nonresonant laser beam. decreased increasing source pressure from 2 to 81 bar. By using effective polarizability directly pertaining force, resulting change in velocity can be evaluated. Theoretical calculations are compared measurements based map imaging techniques. If reduced 295 1 K, maximum alignment increased <cos2 θ>=0.33...
We demonstrate efficient specular reflection of He atoms and molecules from inexpensive, readily available, robust optical gratings. The mechanism is based on diffraction the de Broglie waves by fine grating ridges.
Thermal energy atom scattering at a surface with grazing incidence conditions is an innovative method for investigating dispersive atom-surface interactions potential application in quantum sensing interferometry.The complete establishment of this technique would require detailed peak analysis, which has yet to be achieved.We examined peak-width fluctuations atomic and molecular beams diffracted by grating under conditions.Careful measurements analyses the diffraction patterns He atoms D2...