| Fluctuations and Squeezing in Resonance Fluorescence Emitted Near a Phase Conjugator |
APR 92 |
15 pages |
| Authors:
Henk F. Arnoldus; Thomas F. George; UNIV OF WASHINGTON SEATTLE DEPT OF CHEMISTRY
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 | Atomic resonance fluorescence, emitted near the surface of a four- wave mixing phase conjugator, exhibits squeezing for certain values of the optical parameters of the incident laser field and for a certain range of the phase-conjugate reflectivity. A condition for the occurrence of squeezing is derived, and it is shown that the presence of the phase-conjugating medium tends to increase the quantum fluctuations, thereby diminishing the squeezing. |
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| Spontaneous Decay of an Atom Near a Phase Conjugator |
MAR 92 |
64 pages |
| Authors:
Henk F. Arnoldus; Thomas F. George; WASHINGTON STATE UNIV PULLMAN DEPT OF CHEMISTRY
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| Relaxation of the density operator of an atom near a four-wave mixing phase conjugator (PC) is studied. The relaxation operator Tau can be expressed in the Cartesian components of the atomic dipole operator and correlation functions of the vacuum electromagnetic field. We evaluate these correlation functions in terms of the Fresnel coefficients for reflection and transmission of a polarized monochromatic plane wave. Our expression for Tau includes both linear and ... |
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| Statistics of Fluorescent Photons Emitted Near a Phase Conjugator |
JAN 92 |
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| Authors:
Henk F. Arnoldus; Thomas F. George; Chung I. Um; WASHINGTON STATE UNIV PULLMAN DEPT OF CHEMISTRY
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 | Temporal photon correlations and photon count statistics of fluorescence radiation, emitted by an atom in the vicinity of a phase conjugator, are considered. The fluorescent intensity and the two-photon correlation function are expressed in terms of photon emission operators. An explicit evaluation shows their dependence on the phase-conjugate reflectivity of the surface. The variance of the photon count distribution for long counting times is expressed in terms of the Q-factor, ... |
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| Conditions for Sub-Poissonian Photon Statistics in Phase-Conjugated Resonance Fluorescence |
SEP 91 |
24 pages |
| Authors:
Henk F. Arnoldus; Thomas F. George; WASHINGTON STATE UNIV PULLMAN
|
| Photon correlations and statistics of phase-conjugated resonance fluorescence of a two-state atom is considered. The Q factor, as a function of the incident laser power, the deturning, the laser linewidth and the phase- conjugate reflectivity, has been calculated. It is shown that for small and large reflectivity the statistics is predominantly sub-poissonian. For unit reflectivity the statistics appears to be exactly poissonian (Q = O) for all values of the ... |
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| Phonon Relaxation and Line Shapes of Adsorbates |
JUL 91 |
18 pages |
| Authors:
Henk F. Arnoldus; Thomas F. George; WASHINGTON STATE UNIV PULLMAN DEPT OF CHEMISTRY
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| Relaxation through phonon exchange of adsorbates on the surface of a crystal is considered. The effect of the thermal phonon field on the time evolution of the adsorbate is taken into account with finite memory time reservoir theory. Also, the low-intensity photon absorption profile is evaluated. The spectrum has a sharp cutoff at the Debye frequency of the crystal and a memory induced extra resonance. |
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| Resonance Fluorescence Spectrum of an Atom Near a Phase Conjugator |
APR 91 |
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| Authors:
Henk F. Arnoldus; Thomas F. George; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
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| Resonance fluorescence by an atom near the surface of a phase conjugator is studied. The atom is irradiated by a finite-linewidth laser beam, and the bandwidth is modeled by a randomly fluctuating phase. Expressions for the steady-state atomic density operator and the resonance fluorescence spectrum are obtained. For a small laser linewidth the spectrum contains two delta peaks: the usual peak at the laser frequency, and its phase conjugate image. ... |
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| Heisenberg Approach to Photon Emission Near a Phase Conjugator |
MAR 91 |
26 pages |
| Authors:
Henk F. Arnoldus; Thomas F. George; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
|
| An expression for the emitted fluorescence radiation by an atom near a phase conjugator is derived from a plane-wave expansion of the electric field operator and Heisenberg's equation of motion for the annihilation operator. The result is compared to a solution which was found previously, based on the classical Maxwell equations, where it is shown that both theories yield the same expression for the field in the radiation zone, in ... |
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| Phase-Conjugated Fluorescence |
JAN 91 |
56 pages |
| Authors:
Henk F. Arnoldus; Thomas F. George; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
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| Fluorescent emission by an atom near a phase conjugator (PC) based on four-wave mixing is studied from first principles. The Maxwell Heisenberg equations are solved for the radiation field, and with an asymptotic expansion an expression is derived for the field in the far zone. The total emitted power which can be measured by a detector in this region is evaluated, and it is found that this power acquires three ... |
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| Spectral and Temporal Distribution of Phase-Conjugated Fluorescent Photons |
DEC 90 |
25 pages |
| Authors:
Henk F. Arnoldus; Thomas F. George; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
|
| Spontaneous emission of fluorescence radiation by an atom near the surface of a four-wave mixing phase conjugator is considered. It is shown that the spectral photon distribution consists of two Lorentzians, which have their peaks symmetrically located at the two sides of the pump frequency omega (bar) of the nonlinear crystal. With omega sub 0, the atomic resonance, the line at 2 omega(bar)-omega sub 0 is more than twice as ... |
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| Detection of Three-Photon Relaxation of an Atom near a Phase Conjugator through Absorption Measurements |
SEP 90 |
12 pages |
| Authors:
Henk F. Arnoldus; Thomas F. George; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
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| Spontaneous excitation of an atom near a phase conjugator should be amenable to experimental verification through a measurement of the atomic probe absorption profile. It is shown that the absorption decreases quickly with increasing reflectivity, due to a population of the excited state. The responsible physical process is a three-photon event. Keywords: Phase conjugator, Four wave mixing, Three photon relaxation, Detection, Absorption measurements. (jhd) |
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| Observation of Atomic Relaxation Near an Interface through Detection of Emitted Fluorescence |
NOV 89 |
20 pages |
| Authors:
Henk F. Arnoldus; Thomas F. George; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
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| In this Comment we discuss the general features of spontaneous decay of an atom which is close to the surface of a dielectric (or metal) layer, and this is compared to atomic decay near a four-wave mixing phase conjugator. It is pointed out that the decay or relaxation constants can be expressed entirely in terms of the classical Fresnel coefficients for reflection and transmission of a plane wave, independent of ... |
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| Extraordinary Behavior of Atoms Near a Phase Conjugator |
JUN 89 |
10 pages |
| Authors:
Henk F. Arnoldus; Thomas F. George; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
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| An atom near a phase conjugator (PC) is theoretically seen to behave quite differently than an atom in empty space or an atom near an ordinary (linear) surface. With two laser beams which pump the nonlinear crystal (PC), it is found that an atom in its ground state can fluoresce if it is sufficiently close to a PC. The possible mechanism involves the atomic transition dipole polarizing the PC, which ... |
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| Interference Phenomena in Atomic Emission Near an Interface: Pure Classical Effects in Quantum Radiation |
MAR 89 |
29 pages |
| Authors:
Henk F. Arnoldus; Thomas F. George; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
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| The emission of fluorescence by an atom which is close to the surface of an optically-reflecting medium is examined. All linear media, like a dielectric, a metal, a thin film on a substrate, etc., are dealt with in a unified way. It appears that only the classical Fresnel coefficients for reflection of a plane wave enter the expression for the radiation field. The reflection by nonlinear media is also considered, ... |
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| Fresnel Coefficients for a Phase Conjugator |
OCT 88 |
33 pages |
| Authors:
Henk F. Arnoldus; Thomas F. George; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
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| Optical phase conjugation via four-wave mixing is examined in detail. The Fresnel coefficients for reflection and transmission of a plane wave irradiating the surface of the phase conjugator are calculated. It appears that for normal incidence and a weak nonlinear interaction the device produces the phase-conjugated beam with respect to the incoming beam. For finite angles of incidence or stronger nonlinearities in the crystal, the generated wave deviates from ... |
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| Light Scattering by a Phase Conjugator in the Four-Wave Mixing Configuration |
JUN 88 |
51 pages |
| Authors:
Henk F. Arnoldus; Thomas F. George; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
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| Reflection of travelling and evanescent plane waves by a four-wave mixing phase conjugator is studied in detail. No restrictions are imposed on the nonlinear interaction strength, the angle of incidence or the frequency mismatch between the pump beams and the incoming waves. The incident field is assumed to be weak compared to the pump fields, which justifies a classical-field description of the pumps. The wave vectors, amplitudes and phases for ... |
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| Symmetries of Spontaneous Decay for Atoms Near Any Surface |
JUN 88 |
44 pages |
| Authors:
Henk F. Arnoldus; Thomas F. George; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
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| The structure of spontaneous decay of atoms in the vicinity of a surface is shown to be determined by spatial symmetries. The spontaneous decay operator for a degenerate two level atom is derived, and with symmetry considerations the number of free parameters is reduced to two. Only the dimensionless and normalized inverse lifetimes b-parallel and b-perpendicular for a parallel and perpendicular dipole moment with respect to the surface, respectively, enter ... |
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| Memory-Induced Extra Resonances of Adsorbates |
MAR 88 |
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| Authors:
Henk F. Arnoldus; Thomas F. George; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
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| The optical absorption profile of an atom-surface vibrational bond is studied. From Markovian relaxation theory it follow that the line shape is a Lorentzian around the adsorbate resonance frequency omega sub 0. Dispersion relations for crystals have fairly small cutoff frequency omega sub D, which prohibits the use of such a simple theory. We calculated the spectral profile with finite memory-time reservoir theory, and we found that the modified Lorentzian ... |
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| Memory Effects on Infrared Adsorbate Spectra |
NOV 87 |
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| Authors:
Henk F. Arnoldus; Thomas F. George; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
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| A vibrational bond between an adsorbed atom and a crystal can absorb photons from a weak (probe) laser field (frequency omega). The line shape for this process is usually assumed to be a Lorentzian, which reflects that the kinetic coupling to the phonon reservoir is supposed to be a memoryless process. Due to the finite cutoff of the phonon dispersion relation (Debye frequency omega), this is not an accurate approximation ... |
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| Spontaneous Decay and Atomic Fluorescence Near a Metal Surface of an Absorbing Dielectric |
OCT 87 |
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| Authors:
Henk F. Arnoldus; Thomas F. George; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
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| Optical properties of an atom in the vicinity of a metal or dielectric are different from those in free space. The spontaneous decay of an atom with two degenerate levels is studied, where the relaxation operator is obtained as a function of the atom-surface separation and the complex bulk dielectric constant epsilon(omega). The Einstein coefficient A(m)(e) of an excited state jeme> appears to depend on the magnetic quantum number me. ... |
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| Correlations between Photons in Resonance Fluorescence Emitted by an Atom Near a Metal Surface |
OCT 87 |
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| Authors:
Henk F. Arnoldus; Thomas F. George; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
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| The photon correlations of resonance fluorescence emitted by a degenerate two-level atom near a metal surface are studied. An intense non monochromatic optical laser drives a low lying atomic transition, and the emitted fluorescence is detected by a photon counter. An expression for the spontaneous decay operator is derived, and it appears that the various substates of the upper level have a different lifetime due to the presence of the ... |
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| Correlation Functions in Finite Memory-Time Reservoir Theory |
JUL 87 |
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| Authors:
Henk F. Arnoldus; Thomas F. George; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
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| Interaction of a small system S with a large reservoir R amounts to thermal relaxation of the reduced system density operator rho (t) subs. The presence of the reservoir enters the equation of motion for rho (t) subs through the reservoir correlation functions. Commonly, this time scale is much smaller than the inverse relaxation constants for the time evolution of rho (t) subs . Then a series of approximations can ... |
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| Fluorescence at a Surface |
JUN 87 |
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| Authors:
Henk F. Arnoldus; P. T. Leung; Thomas F. George; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
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| Fluorescence emitted by an atom near a metal surface and the coupling of the surface plasmon field of a dielectric substrate to a molecular electronic transition are studied. Explicit expressions for the atomic and molecular lifetimes are derived. It is shown how the (classical) phase shift of a plane wave upon reflection at the surface is responsible for the alteration of atomic lifetimes. Subsequently, it is demonstrated that the dipole ... |
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| Quantum Theory of Atomic Fluorescence Near a Metal Surface |
JUN 87 |
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| Authors:
Henk F. Arnoldus; Thomas F. George; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
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| Quantum electrodynamics of an atom near a surface is a timely problem in current theoretical research. It appears, however, that a full dynamical theory, which includes both the time evolution of the atomic density operator and the details of the fluorescence radiation (temporal photon distribution) has never been formulated. In this paper the quantum theory of an atom near a perfect conductor is presented, and it is indicated how the ... |
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| Non-Markovian Line Shapes of Physisorbed Atoms on a Crystal |
APR 87 |
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| Authors:
Henk F. Arnoldus; Thomas F. George; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
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| An atom adsorbed on the surface of a harmonic crystal is considered. The binding potential well supports many vibrational bound-harmonic and the coupling of the motion of the atom with the substrate gives rise to phonon- exchange reactions, which subsequently amount to atomic transitions between the bound states. This process of thermal relaxation of the adatom density operator is commonly described with reservoir theory, in which the crystal is regarded ... |
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| Confinement and Redistribution of Charges and Currents on a Surface by External Fields |
JAN 87 |
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| Authors:
Henk F. Arnoldus; Daniel Jelski; Thomas F. George; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
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| The old problem of light scattering from a perfectly conducting surface is addressed. An electromagnetic field is incident upon the boundary, where it induces a charge and current distribution. These charges and currents emit the reflected fields. A set of equations for the charges and currents on the surface is derived by eliminating the E- and B-fields from Maxwell's equations with the aid of the appropriate boundary conditions. An explicit ... |
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| Interaction of an Adsorbed Atom with a Laser |
DEC 86 |
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| Authors:
Henk F. Arnoldus; Sander van Smaalen; Thomas F. George; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
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| The irradiation by infrared laser light of an atom adsorbed on the surface of a harmonic crystal is considered. The dynamic coupling between the atom (its motion) and the substrate degrees of freedom (phonon field) in the presence of a confining potential well (van der Waals bond between atom and crystal) gives rise to thermal relaxation of this adbond configuration. Both the atom and the substrate are assumed to be ... |
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| Role of Coherences in the Relaxation of Adsorbates |
DEC 86 |
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| Authors:
Henk F. Arnoldus; Thomas F. George; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
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| Adsorbed species on a solid-state surface interact with the large number of substrate modes, which gives rise to thermal relaxation. Commonly, the temporal evolution of the quantum state of the adsorbate is described by a master equation for the level populations (vibrational bond, internal modes, etc). It is pointed out that this approach does not necessarily give a correct account of the coupling to the solid when the effective level-widths ... |
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| Laser-Heating of a Transparent Crystal via Adsorbed Atoms |
OCT 86 |
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| Authors:
Sander van Smaalen; Henk F. Arnoldus; Thomas F. George; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
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| A coated surface of a crystal is irradiated by intense infrared light. The optically active atomic bonds absorb photons from the laser field, and the subsequent spontaneous decay goes together with emissions of phonons into the crystal. This photon phonon conversion results in an energy flux into the crystal. An equation for this flux is derived from the master equation for the level populations of the dressed atomic states. The ... |
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| Dynamics of a Laser-Irradiated Adatom |
SEP 86 |
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| Authors:
Sander van Smaalen; Andre Peremans; Henk F. Arnoldus; Thomas F. George; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
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| The dynamics of an adsorbed atom irradiated by an IR laser in resonance with a single pair of states of the vibrational adbond is studied. Using a non-perturbative treatment for the laser adbond interaction, a master equation is derived, which governs the time evolution of the populations of the laser dressed states of the adbond. The effect of resonant heating and laser induced desorpton, as an example of a possible ... |
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| Multiplicative Stochastic Processes Involving the Time-Derivative of a Markov Process |
JUL 86 |
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| Authors:
Henk F. Arnoldus; Thomas F. George; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
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| The characteristic functional of the derivative phi(t) of a Markov process phi(t) and the related multiplicative process sigma(t), which obeys the stochastic differential equation isigma(t) = (A + phi(t)B)sigma(t), have been studied. Exact equations for the marginal characteristic functional and the marginal average of sigma(t) are derived. The first equation is applied to obtain a set of equations for the marginal moments of phi(t) in terms of the prescribed properties ... |
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| Thermal Relaxation of Adsorbed Atoms in an Intense Laser Field |
JUL 86 |
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| Authors:
Henk F. Arnoldus; Sander van Smaalen; Thomas F. George; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
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| Adsorbed atoms on the surface of a harmonic lattice are immersed in a strong laser field. The optical Bloch equations are derived, which include the thermal relaxation and the coherent excitation of the adbond. This is accomplished by a transformation to dressed states, which diagonalizes the interaction with the laser. The single phonon couplings are then understood as transitions between dressed states. The radiative contributions for arbitrary strong fields are ... |
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| Laser-Linewidth Effects on the Photon-Phonon Conversion Rate at a Gas- Solid Interface |
JUL 86 |
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| Authors:
Henk F. Arnoldus; Thomas F. George; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
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| An atom, bounded to the surface of a crystal, absorbs photons from a strong incident laser field and subsequently emits phonons into the solid. This paper studies the influence of the laser linewidth of this photon phonon conversion process. The appearance of coherences obscures the interpretation of the equation of motion in terms of transition rates and prohibits the derivation of a master equation in the transient region. The absorbed ... |
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Reports by Author
