A laser-excited three-level atom

1990 ◽  
Vol 68 (3) ◽  
pp. 321-333 ◽  
Author(s):  
Constantine Mavroyannis
Keyword(s):  
Excited States ◽  
Laser Field ◽  
Excitation Spectra ◽  
Spectral Functions ◽  
Laser Fields ◽  
At Resonance ◽  
Level Atom ◽  
Short Lifetime ◽  
Strong Transition ◽  
Long Lifetime

We considered the excitation spectra for the excited states of a three-level atom, where the strong and the weak atomic transitions are driven by resonant and nonresonant laser fields, respectively. The spectral functions describing the excitation spectra for the electric dipole allowed excited state and for the metastable state of the atom have been derived when both laser fields are quantized as well as when they are treated as classical entities. In the low-intensity limit of the laser field operating in the strong transition, there are two short-lifetime excitations, the spontaneous one and the induced one, which appear at the same frequency, and a long-lifetime excitation induced by the weak laser field. These excitations compete with each other at resonance as well as at finite detunings of the weak laser field. In the high-intensity limit of the laser field operating in the strong transition, the competition is between the short- and the long-lifetime side bands, which are induced by the strong and the weak laser fields, respectively. The ratio of the maximum intensities of the peaks describing the long- and the short-lifetime excitations exhibits a resonance variation with the detuning of the weak laser field. Comparison between the results obtained when the laser fields are treated as quantized and as classical entities is made.

A laser-excited three-level atom. II numerical results

1990 ◽  
Vol 68 (4-5) ◽  
pp. 411-421 ◽  
Author(s):  
Constantine Mavroyannis
Keyword(s):  
Excited State ◽  
Laser Field ◽  
Spectral Width ◽  
Spectral Functions ◽  
Laser Fields ◽  
Atomic Transitions ◽  
Level Atom ◽  
Short Lifetime ◽  
Strong Transition ◽  
Long Lifetime

Numerical calculations are presented for the interference spectra of a laser-excited three-level atom, where the strong and the weak atomic transitions are driven by resonant and nonresonant laser fields, respectively. The spectral functions describing the interference spectra for the electric dipole allowed excited state have been considered in the low- and high-intensity limit of the laser field operating in the strong transition. The interference spectra arise from the competition between short-lifetime spontaneous processes and short- and long-lifetime excitations induced by the strong and the weak laser fields, respectively. Both laser fields have been treated as quantized and as classical entities. The computed spectra have been presented graphically for different values of the Rabi frequencies and detunings of the weak laser field. It is shown that the decrease in the intensity of the short-lifetime excitation may provide a measure of the spectral width of the long-lifetime excitation.

Optical mixing of frequencies of a strong bichromatic field interacting with a three-level atom. II. Numerical results

1982 ◽  
Vol 60 (2) ◽  
pp. 245-251 ◽  
Author(s):  
Constantine Mavroyannis ◽  
K. J. Woloschuk ◽  
D. A. Hutchinson ◽  
Christine Downie
Keyword(s):  
Ground State ◽  
Laser Field ◽  
Excitation Spectra ◽  
Laser Fields ◽  
Level Atom ◽  
Reduced Frequency ◽  
Spontaneous Emission Probability ◽  
Bichromatic Field ◽  
Optical Mixing ◽  
Selection Of

We have numerically calculated the excitation spectra arising from the 3rd order mixing of the frequencies ωa and ωb of two laser fields interacting with a three-level atom, where each laser field resonantly couples the ground state with each excited state of the atom, respectively. In the limit of high photon densities, the excitation spectra near the reduced frequency X = (ω−ωa + 2ωb)/γ0 ≈ 0 are considered as a function of the reduced Rabi frequencies ηa and ηb of the two laser fields, respectively and γ0 is the spontaneous emission probability. For ηa < ηb the spectra consist of a doublet peaked at [Formula: see text] and its intensity is constant. When ηa = ηb, the spectra are composed of five pairs of bands peaked at [Formula: see text], and [Formula: see text]. When ηa < ηb the computed spectra consist of five pairs of bands, where the intensities of the peaks at [Formula: see text] and [Formula: see text] are positive indicating absorption, those at [Formula: see text] are negative implying amplification, and the two pairs of peaks at [Formula: see text] have positive and negative components describing the mixed process of absorption–amplification. The intensities of these bands are found to vary as (ηa/ηb)2 for (ηa/ηb) > 1 and, therefore, the intensities of the bands are immensely enhanced as the value of the ratio (ηa/ηb) increases. The computed spectra for a wide selection of Rabi frequencies are graphically presented and compared with those derived by analytical methods.

Resonance fluorescence spectra from a three level atom interacting with a strong bichromatic field: induced two photon transitions

1983 ◽  
Vol 61 (1) ◽  
pp. 15-29 ◽  
Author(s):  
Douglas A. Hutchinson ◽  
Christine Downie ◽  
Constantine Mavroyannis
Keyword(s):  
Ground State ◽  
Rabi Frequency ◽  
Resonance Fluorescence ◽  
Excitation Spectra ◽  
Laser Fields ◽  
Two Photon ◽  
Photon Transition ◽  
Level Atom ◽  
Photon Excitation ◽  
The One

This investigation describes the interaction of a three level atom with two laser fields. One of the transitions from the ground state is in resonance with twice the frequency of the first laser and the other transition from the ground state is in resonance with the second laser. The Green's function formalism is used to derive expressions from which the induced two photon and one photon excitation spectra are computed. Also, approximate expressions are derived for the excitation spectra in the appropriate frequency regions. These results agree well with the numerical computations based upon the precise expressions. The interference between the two transitions produce some splittings; these splittings depend upon the Rabi frequency of the one photon transition. The intensities of the weak peaks depend upon the ratio of the Rabi frequency of the two photon transition to the frequency of the first laser. Some features of the excitation spectra are interpreted in terms of previous knowledge about the behavior of two level atoms in strong laser fields.

Interference spectra in a two-level atom

1990 ◽  
Vol 68 (12) ◽  
pp. 1389-1395 ◽  
Author(s):  
Constantine Mavroyannis
Keyword(s):  
Excited State ◽  
High Intensity ◽  
Laser Field ◽  
Stark Effect ◽  
Ground States ◽  
Spectral Functions ◽  
Laser Photon ◽  
Level Atom ◽  
Dynamic Stark Effect ◽  
Two Peaks

We have considered the interference spectra arising from the competition between a spontaneous process and one induced by a laser field in a two-level atom. Expressions for the spectral functions have been derived describing the spectra of the excited and ground states of the atom in the low- and high-intensity limit of the laser field. For the excited-state spectra in the low-intensity limit, the frequency profiles of the two peaks, which arise from the spontaneous and the induced processes, cancel each other out completely near the center of the line, while for the ground state the induced process dominates. For finite values of the detuning, the spectra of the excited state consist of two peaks, which have positive and negative frequency profiles, respectively. The computed spectra have been graphically presented and discussed. In the high-intensity limit, the dynamic Stark effect dominates the spectra of the excited and ground states of the atom. Expressions for the correlation functions have been derived that describe the emission or the absorption of a laser photon at two different times. The derived expressions for the corresponding delay functions in the low- and high-intensity limits have been found to be identical to those recently proposed in the literature. The laser field has been treated as a classical as well as a quantized entity.

Excitation spectra for the V configuration of a three-level atom in resonance with two laser fields

1985 ◽  
Vol 63 (2) ◽  
pp. 144-150
Author(s):  
D. A. Hutchinson
Keyword(s):  
Excited States ◽  
Excitation Spectrum ◽  
Ground State ◽  
Central Peak ◽  
Decay Rates ◽  
Closed Form Expression ◽  
Form Expression ◽  
Excitation Spectra ◽  
Level Atom ◽  
Special Cases

The excitation spectrum is calculated for a three-level atom interacting with two strong electromagnetic fields. The two fields are in resonance with the atomic transition frequencies from the ground state to the two excited states. The excitation spectrum consists of a central peak and two pairs of side bands for each of the two transitions. If the decay rates of the two excited states are equal a relatively simple closed form expression is derived for the excitation spectrum. For unequal decay rates numerical methods are used to determine the excitation spectrum for selected special cases.

Excitation spectra of a three-level atom in the "lambda" configuration at high photon densities. II. Numerical results

1982 ◽  
Vol 60 (7) ◽  
pp. 968-976 ◽  
Author(s):  
K. J. Woloschuk ◽  
S. Hontzeas ◽  
Constantine Mavroyannis
Keyword(s):  
Electromagnetic Field ◽  
Laser Field ◽  
Excitation Spectra ◽  
Two Photon ◽  
Level Atom ◽  
Forbidden Transition ◽  
Wide Range ◽  
Spectral Intensities ◽  
Photon Resonance ◽  
Resonance Process

We have performed a numerical calculation for the excitation spectra arising from the interaction of a three-level atom in the lambda configuration with a strong electromagnetic field whose frequency mode is initially populated. The excitation spectra are considered for equal detunings, which refer to the cooperative two-photon resonance process, as well as for different detunings. The computed cooperative two-photon resonance spectra are compared with those derived by analytical methods. In the presence of different detunings, conditions are established under which the laser field induces sidebands at the frequency equal to that for the forbidden transition. Numerical calculations for a wide range of Rabi frequencies and detunings are presented graphically. Detailed discussion of the computed spectral intensities is given and a comparison is made between the spectra of three-level atoms in the lambda and cascade configurations.

RESONANCE FLUORESCENCE THEORY ANALYZED BY SUPERSYMMETRIC TRANSFORMATION

2000 ◽  
Vol 14 (03) ◽  
pp. 95-102 ◽  
Author(s):  
HONG-YI FAN ◽  
XIAN-TING LIANG
Keyword(s):  
Laser Field ◽  
Single Mode ◽  
Resonance Fluorescence ◽  
Physical Processes ◽  
Laser Fields ◽  
Strong Laser Field ◽  
Mode Laser ◽  
Single Mode Laser ◽  
Strong Laser ◽  
Level Atom

In this paper, use is made of supersymmetric transformation to discuss resonance fluorescence of two-level atom driven by a strong laser field and that of three-level atom driven by two single-mode laser fields. The supersymmetric derivation makes the analysis of the physical processes more accurate, clear and efficient. As a result, some new physical processes are revealed by this method.

scholarly journals Photochemical R2PI study of chirality and intermolecular forces in supersonic beam

2001 ◽  
Vol 3 (4) ◽  
pp. 223-227 ◽  
Author(s):  
A. Giardini Guidoni ◽  
S. Piccirillo ◽  
D. Scuderi ◽  
M. Satta ◽  
T. M. Di Palma ◽  
...  
Keyword(s):  
Excited States ◽  
Molecular Beam ◽  
Intermolecular Forces ◽  
Excitation Spectra ◽  
Supersonic Molecular Beam ◽  
Spectral Shifts ◽  
Band Origin ◽  
Solvent Molecules ◽  
The One ◽  
Diastereomeric Complexes

One and two-color, mass selected R2PI spectra of theS1←S0transitions in the bare(+)-(R)- 1-phenyl-1-ethanol(ER) and its complexes with different solvent molecules (solv) (-)-(R)-2-butanol(BR) or(+)-(S)-2-butanol(BS), (—)-(R)-2-pentanol (TR) or(+)-(S)-2-pentanol(TS) and(-)-(R)-2-butylamine(AR) or(+)-(S)-2-butylamine(AS), have been recorded after a supersonic molecular beam expansion. The one-color R2PI excitation spectra of the diastereomeric complexes are characterized by significant shifts of their band origin relative to that of bareER. The extent and the direction of these spectral shifts are found to depend upon the structure and the configuration ofsolvand are attributed to different short-range interactions in the ground and excited states of the complexes. In analogy with other diastereomeric complexes, the phenomenological binding energy of the homochiral cluster is found to be greater than that of the heterochiral one. Preliminary measurements of excitation spectrum of(+)-(R)-1-Indanol(IR) is also reported.

Sign in / Sign up

Export Citation Format

Share Document