Showing papers on "Stark effect published in 1980"
TL;DR: The microwave rotational spectrum of the hydrogen-bonded, linear heterodimer HCN has been identified and a number of spectroscopic constants have been measured in a detailed analysis as mentioned in this paper.
Abstract: The microwave rotational spectrum of the hydrogen-bonded, linear heterodimer HCN • • • HF has been identified and a number of spectroscopic constants have been measured in a detailed analysis. The spectroscopic constants have been used in a variety of ways in order to evaluate parameters characterizing the potential energy function of the isolated dimer. An investigation of the Stark effect of two rotational transitions of HCN • • • HF has led to an accurate value of the electric dipole moment of the dimer and hence to the enhancement on dimer formation.
119 citations
TL;DR: In this article, the authors used coherent anti-Stokes Raman spectroscopy for hydrogen and nitrogen detection and showed that the magnitude of the observed shift is in agreement with a calculation which considers the coupling of the optical field to the internuclear separation via the molecular electronic polarizability.
Abstract: Vibrational and rotational Raman transitions are shown to be shifted to lower frequencies in the presence of a nonresonant, high-intensity optical field. Experimental results using coherent anti-Stokes Raman spectroscopy for hydrogen and nitrogen are presented. The magnitude of the observed shift is in agreement with a calculation which considers the coupling of the optical field to the internuclear separation via the molecular electronic polarizability. The magnitude of the shift is predicted to be proportional to the optical field intensity.
94 citations
93 citations
TL;DR: In this paper, the asymptotic behavior of the resonances in the hydrogen Stark effect at both small and large fields is related to the high-order behaviour of the Rayleigh-Schrodinger perturbation coefficients of the two-dimensional rotationally symmetric anharmonic oscillator.
Abstract: The asymptotic behaviour of the resonances in the hydrogen Stark effect at both small and large fields is related to the high-order behaviour of the Rayleigh-Schrodinger perturbation coefficients of the two-dimensional rotationally symmetric anharmonic oscillator. For two resonances at intermediate fields exhaustive numerical results are given, which provide an excellent matching between the two asymptotic behaviours. For the anharmonic oscillator eigenvalues Rayleigh-Ritz-like approximants are used which are uniformly asymptotic in the Watson sense.
81 citations
TL;DR: In this paper, an unambiguous classification of the Stark states is presented which correlates a given Stark state to a unique zero-field state; this classification is valid for any Stark states-resonant or non-reonant-and at any energy smaller or greater than E0 the ionisation limit of the unperturbed atom.
Abstract: An exact method which allows the authors to obtain normalised wavefunctions for a hydrogen-like atom in the presence of a uniform electric field is reported. An unambiguous classification of the Stark states is presented which correlates a given Stark state to a unique zero-field state; this classification is valid for any Stark states-resonant or non-resonant-and at any energy smaller or greater than E0 the ionisation limit of the unperturbed atom. From the supersymmetry in the hydrogen spectrum, states with different values for m, the magnetic quantum number, or for n1, the generalised parabolic quantum number, can be considered independently. A parabolic critical energy can be defined for any state m, n1; for sufficiently high value of n1 the critical energy is greater than E0. A systematic study of the positions and widths of the resonance in a broad energy range below E0 is presented.
75 citations
TL;DR: In this article, a model was developed to describe nondegenerate four-wave mixing in a medium characterized by a single strong atomic resonance, and the nonlinear response was calculated using the density-matrix formalism, and propagation effects were included by solving coupled-wave equations.
Abstract: A model is developed to describe nondegenerate four-wave mixing in a medium characterized by a single strong atomic resonance. The nonlinear response is calculated using the density-matrix formalism, and propagation effects are included by solving coupled-wave equations. This model predicts large resonant responses for signals detuned from the pump frequency by approximately the generalized Rabi frequency. Potential applications of the effects predicted by this model include construction of tunable bandpass filters and four-wave parametric oscillators.
54 citations
TL;DR: In this paper, the principle of bistable operation with two independent input optical beams is presented; the nonlinear medium inside a Fabry-Perot resonator is in two-photon resonance with the beams.
Abstract: The principle of bistable operation with two independent input optical beams is presented; the nonlinear medium inside a Fabry-Perot resonator is in two-photon resonance with the beams. The transmission characteristics of the bistable device are derived in both the absorptive and the dispersive regimes. The degenerate case, and the effect of a new parameter associated with the optical Stark shift in a two-photon process, are also discussed.
50 citations
TL;DR: In this paper, the effect of laser light statistics on two-photon resonant threephoton ionisation of sodium was analyzed in the presence of an intensity stabilised laser with a diffusing phase (phase diffusion model) and light undergoing Gaussian amplitude fluctuations (chaotic field).
Abstract: Presents a theoretical analysis of the effect of laser light statistics on two-photon resonant three-photon ionisation of sodium. The ionisation probability and the population of the atom in the resonant state are compared in the presence of an intensity stabilised laser with a diffusing phase (phase diffusion model) and light undergoing Gaussian amplitude fluctuations (chaotic field). In the limit of large bandwidth fields the resonant two-photon excitation is statistically decoupled from the following ionisation step. A decrease of the bandwidth results in a partial correlation between these two steps manifesting itself in an enhancement of the ionisation probability in the chaotic field. With increasing intensity and the onset of saturation of the bound-bound transition, the ionisation probability and resonant excited-state population in the chaotic field may become smaller than the one in the phase diffusing light. In the large-bandwidth limit the Stark shift in the chaotic field is enhanced, which has a pronounced effect on the effective power-law dependence of the ionisation probability.
42 citations
TL;DR: In this paper, the authors have made new molecular beam spectroscopy measurements of the ratio of the Stark effect of CH3F in the J = 1, K = 1 and J = 2, K 2 and K 3F states to the ground vibrational state of OCS.
40 citations
TL;DR: In this paper, the unresolved Stark patterns of the b -type transitions are analyzed by the use of computer simulation, including second-order perturbation theory, including the effect of spin-doublings in the denominators, is used for the calculation of the Stark effect coefficients.
40 citations
TL;DR: In this article, rotational spectra assignable to gas phase cis-and trans-ethylidenimine (CH3CH=NH) have been detected in the pyrolysis decomposition products from several alkylamines and from the ring trimer.
Abstract: Microwave rotational spectra assignable to gas phase cis‐ and trans‐ethylidenimine (CH3CH=NH) have been detected in the pyrolysis decomposition products from several alkylamines and from the ring trimer, (CH3CHNH)3. Stark effects, hyperfine and internal rotation splittings have aided the assignment of the observed spectra and allowed the determination of rotational distortion constants, 14N nuclear electric quadrupole coupling constants, internal rotation barriers, and electric dipole moments. Limited structural information was also obtained.
TL;DR: In this article, the authors studied the microwave and radiofrequency spectra of the Ar⋅SO2 van der Waals molecule using molecular beam spectroscopy and showed that it has Cs point group symmetry and tunnels through a very low barrier at a C2v structure at a 980 MHz rate.
Abstract: Microwave and radiofrequency spectra of the Ar⋅SO2 van der Waals molecule have been studied by molecular beam spectroscopy. The molecule has Cs point group symmetry and tunnels through a very low barrier at a C2v structure at a 980 MHz rate. The tunneling interchanges the two oxygen atoms which causes half of each inversion doublet to have zero statistical weight. The inversion frequency and assumptions about the bending vibration lead to a barrier height of ?10 cm−1. Stark effect measurements give μa=0.2674 D, μb=0.0 D, μc=1.465 D. These moments are interpreted in terms of a vibrational amplitude of 24° associated with the inversion coordinate. The geometry of the complex is essentially perpendicular with the Ar atom above the plane of SO2 and located almost directly over the SO2 center‐of‐mass at a 3.675 A distance.
TL;DR: In this paper, the polarizability anisotropy of I2 was measured in a molecular beam magnetic resonance experiment using laser induced fluorescence for state selection and detection, and a Stark field of up to 16 kV/cm produced 50 kHz frequency shifts and α∥−α⊥=6.69±5% A3.
Abstract: The polarizability anisotropy of I2 has been measured in a molecular beam magnetic resonance experiment using laser induced fluorescence for state selection and detection. Stark fields of up to 16 kV/cm produced 50 kHz frequency shifts and α∥−α⊥=6.69±5% A3.
TL;DR: In this paper, the enhancement effect observed for many laser lines, both "orthogonal" and "parallel", is analyzed as a function of different parameters such as gas pressure, laser threshold, cavity tuning, and transitions selection rules.
Abstract: The FIR power dependence on an applied electric field is carefully investigated for optically pumped lasers. The enhancement effect observed for many laser lines, both "orthogonal" and "parallel," is analyzed as a function of different parameters such as gas pressure, laser threshold, cavity tuning, and transitions selection rules. Measurements of the IR absorption of the gases are also carried out by a Stark optoacoustic technique. Absorption increases are observed at low electric field values. The experimental results disagree with the previously proposed linear Hanle effect explanation. They are explained with the increase in the pump saturation intensity, also detected with the transferred Lamb-dip technique. The combined effects of the absorption increase and of the small-signal gain curve decrease are shown to qualitatively explain the observed FIR enhancement features.
TL;DR: In this paper, it was shown that for the ground state of the hydrogen Stark problem the $n$ th order of the perturbation expansion is a polynomial of order n with integer coefficients.
Abstract: Separation equations in parabolic coordinates are written in terms of the logarithmic derivative of the wave function. It is shown that for the ground state of the hydrogen Stark problem the $n$ th order of the perturbation expansion is a polynomial of order $n$ with integer coefficients. The energy coefficients. The energy coefficients, suitably defined, are integers and the calculation of the first 30 coefficients is listed.
TL;DR: In this article, the Stark effect was used to assign far-infrared emission lines observed in infrared laser-pumped CH 3 OH molecules to a set of energy levels which were not predicted by current models for the vibrationally excited CH 3OH molecule.
Book•
01 Jan 1980
TL;DR: In this paper, the authors proposed a method to detect superradiance by quantized field treatment and showed that this method can be used in high-resolution spectroscopy applications.
Abstract: 1. Coherent Nonlinear Optics.- 1.1 Introductory Comments.- References.- 2. Superradiance.- 2.1 Background Material.- 2.2 Physical Principles.- 2.3 Theoretical Treatments.- 2.3.1 Initiation of Superradiance: Quantized Field Treatment.- 2.3.2 Semiclassical Theory.- 2.4 Results of the Theory.- 2.4.1 Superradiance in the Ideal Limit.- 2.4.2 Influence of Quantum Fluctuations.- 2.4.3 Deviations from Ideal Behavior.- Finite Inversion Time.- Uniform Inversion: Cooperation Length.- Decay and Dephasing Times.- Feedback Initial Polarization.- Initial Polarization.- 2.4.4 Further Discussion of the Basic Assumptions.- Neglect of Interaction of Forward and Backward Waves.- Limitations of the Plane Wave Approximation.- 2.4.5 Point Sample Superradiance.- 2.5 Relation to Other Coherent Phenomena.- 2.5.1 Limited Superradiance.- 2.5.2 Transient Phenomena in Optically Thick Media.- 2.5.3 Stimulated and Superradiant Emission.- 2.6 Experiments.- 2.6.1 Experimental Observation of Superradiance.- 2.6.2 Recent Experimental Results.- 2.6.3 Comparison with Theory.- 2.7 Concluding Remarks.- 2.7.1 Applications.- 2.7.2 Summary.- References.- 3. Coherence in High Resolution Spectroscopy.- 3.1 Coherent Phenomena in Resonant Processes.- 3.2 Coherent Phenomena in Saturated Absorption Spectroscopy.- 3.2.1 Standing Wave.- 3.2.2 Probe Wave Resonances.- Oppositely Traveling Waves.- Unidirectional Waves.- High-Frequency Stark Effect on Doppler Broadened Transitions.- Spectroscopic Applications. Measurement of Relaxation Constants.- Study of Level Structures and Separation of Weak Lines.- Optical Instability. Generation Stability.- Recoil Effect.- 3.2.3 Influence of Collisions on Coherent Processes.- Study of Relaxation Processes.- Dipole Scattering.- Influence of the Elastic Scattering Without Phase Randomization on Resonance Characteristics.- 3.3 Coherent Phenomena in Multilevel Systems.- 3.3.1 Resonant Processes in Three-Level Systems.- 3.3.2 Two-Photon Resonances.- 3.3.3 Relation to Other Phenomena.- 3.4 Method of Separated Optical Fields.- 3.4.1 Two-Photon Resonance in Separated Fields.- Narrow Two-Photon Absorption Resonances of the Sequence of Supershort Pulses in a Gas.- 3.4.2 Resonance in Separated Fields for Two-Level Atoms.- 3.4.3 Coherent Radiation and Macroscopic Polarization Transfer in Separated Fields.- 3.4.4 Properties of Coherent Radiation in Separated Fields.- Destruction of an Interference Structure and Attainment of Resonances with a Radiative Width.- Particle Scattering.- 3.4.5 Coherent Raman Scattering in Separated Fields.- 3.4.6 Transient Resonant Coherent Effects.- References.- 4. Multiphoton Resonant Processes in Atoms.- 4.1 Various Experimental Aspects of Resonant Multiphoton Transitions in Atoms.- 4.1.1 Selective Pumping of an Excited Level with Multiphoton Transition.- 4.1.2 Intermediate Step in Other Processes.- 4.1.3 Spectroscopy Using Broadband Lasers.- 4.2 Doppler-Free Two-Photon Experiments.- 4.2.1 Principle of Doppler-Free Multiphoton Transitions.- 4.2.2 Experimental Observation of Doppler-Free Two-Photon Transitions.- Typical Experiment in Sodium.- Thermoionic Detection.- 4.2.3 Doppler-Free Two-Photon Transitions in Hydrogen.- 4.2.4 Other Possibilities of Doppler-Free Two-Photon Transitions.- 4.2.5 Experiments with Two Different Light Sources.- 4.3 Theory of Two-Photon Transitions in Atoms.- 4.3.1 The Effective Hamiltonian.- 4.3.2 Solution of the Density Matrix Equation.- 4.3.3 Case of Two Waves with Complex Polarizations.- 4.3.4 Two-Photon Line Shape in Vapors.- 4.3.5 Light Shifts.- Comparison with Experiments.- 4.3.6 Selection Rules for Two-Photon Transitions.- 4.4 Multiphoton Transitions.- 4.4.1 Generalization of the Effective Hamiltonian.- 4.4.2 Discussion of the Light Shifts.- Case of a Standing Wave.- 4.4.3 Application to Multiphoton Ionization.- 4.4.4 Doppler-Free Three-Photon Transition.- 4.4.5 Three-Photon Selection Rules.- 4.5 Dispersion Near a Two-Photon Resonance.- 4.5.1 Refractive Index for a Travelling Wave.- 4.5.2 Refractive Indices for Two Waves of Different Frequencies.- 4.5.3 Refractive Index for a Standing Wave.- 4.6 Transient Processes Involving Doppler-Free Two-Photon Excitation.- 4.6.1 Free Induction Transients.- 4.6.2 Transients in the Driven Regime.- References.- 5. Coherent Excitation of Multilevel Systems by Laser Light.- 5.1 Multilevel Molecular Systems.- 5.1.1 The Schrodinger Equation for Multilevel Systems in the Rotating-Wave Approximation.- 5.1.2 "Quasi-Energy" or "Dressed-States" Approach for Multilevel Systems.- Constant Optical Electric Field.- Adiabatic Switching on of the Field.- 5.2 Interaction of Equidistant Nondegenerate Multilevel Systems with a Quasi-Resonant Field.- 5.2.1 Analytical Solutions for an Exactly Resonant Field.- Harmonic Oscillator.- Infinite System with Equal Dipole Moments.- A System with Decreasing Dipole Moments.- N-Level System with Equal Dipole Moments.- 5.2.2 Does Resonance Always Result in Effective Excitation?.- 5.2.3 Nonexact Resonance and Its Compensation by Power Broadening.- Step-Function Laser Pulse.- Adiabatically Switched-On Pulse.- General Estimates for Maximum Detuning.- 5.3 Interaction of Nonequidistant Multilevel Systems with a Quasi-Resonant Field.- 5.3.1 Multiphoton Resonances.- Rabi Frequency for Multiphoton Transitions.- 5.3.2 Numerical Calculations for Multilevel Systems.- 5.3.3 Dynamic Stark Effect and Frequency Shifts.- An Analytically Solvable Example.- General Approach to an Approximate Description of the Dynamics of Oscillator-Type Systems.- Upper Subsystem - Harmonic Oscillator.- Upper Subsystem with Equal Dipole Moments.- 5.3.4 "Leakage" from the Lower Quantum States into the Upper Levels.- 5.3.5 Excitation of Multiplet Systems with a Quasi-Continuous Structure of Transitions.- 5.4 Excitation of Triply-Degenerate Vibrational Modes of Spherical-Top Molecules.- 5.4.1 Vibrational States and Vibrational Hamiltonian.- Expression of the Hamiltonian in Terms of Cartesian Creation and Annihilation Operators.- Orders of Magnitude of Anharmonic Operators.- Final Form of the Vibrational Hamiltonian.- Comparison with Hecht's Hamiltonian.- The Spherical Vibrational Basis.- Eigenvalues of the Vibrational Hamiltonian.- 5.4.2 Physical Significance of Vibrational Anharmonic Parameters.- 5.4.3 Rotational States and Vibration-Rotation Bases.- Rigid-Rotor Wave Functions.- Coupled Vibration-Rotation Basis.- Symmetry-Adapted Vibration-Rotation Basis.- 5.4.4 Vibration-Rotation Hamiltonian.- 5.4.5 Dipole Transition Moments in Spherical-Top Molecules.- 5.4.6 Experimental Determination of the Anharmonic Parameters of the v3 Mode of SF6.- Effective-State Models for Molecular Multiphoton Calculations.- Absorption Strength of an Ensemble of Two-Level Systems.- Effective-State Equations of Motion.- Dipole Transition Moments Between Effective States.- Calculation of Degeneracies and Transition Strengths.- 5.4.8 Calculation of Multiphoton Excitation Including a Thermal Distribution of Initial State.- 5.4.9 Numerical Calculations of Multiphoton Excitation of SF6.- References.- 6. Coherent Picosecond Interactions.- 6.1 Overview.- 6.2 Theory of Investigations.- 6.2.1 Excitation Process.- 6.2.2 Coherent Probing.- 6.3 Experimental.- 6.3.1 Generation of Ultrashort Laser Pulses.- 6.3.2 Coherent Excitation and Probing Techniques.- 6.4 Experimental Results and Discussion.- 6.4.1 Modes with Homogeneous Line Broadening.- 6.4.2 Modes with Discrete Substructure.- 6.4.3 Modes with Inhomogeneous Line Broadening.- 6.4.4 Vibrational Modes in Solids.- 6.5 Interaction Processes.- References.- 7. Coherent Raman Spectroscopy.- 7.1 Historical Background.- 7.1.1 Prehistory.- 7.1.2 The Tunable Laser Era.- 7.2 Theory.- 7.2.1 Extended Two-Level Model for Coherent Raman Spectroscopy.- 7.2.2 The Nonlinear Polarization.- Stimulated Raman Gain and Loss Spectroscopy, and the Raman Induced Kerr Effect.- Coherent Anti-Stokes and Coherent Stokes Raman Spectroscopy.- Four-Wave Mixing.- Photoacoustic Raman Spectroscopy.- 7.2.3 The Nonlinear Susceptibility Tensor.- 7.2.4 Doppler Broadening.- 7.2.5 Symmetry Considerations.- 7.2.6 Relationship Between xR and the Spontaneous Cross Section.- 7.2.7 The Coherent Raman Signal.- 7.2.8 Focusing Considerations.- 7.2.9 Accentric Crystals and Polaritons.- 7.2.10 Resonant Effects and Absorbing Samples.- 7.3 Experimental Techniques.- 7.3.1 CARS in Liquids and Solids.- 7.3.2 CARS in Gases: Pulsed Laser Techniques.- 7.3.3 Multiplex CARS.- 7.3.4 CW CARS.- 7.3.5 Nonlinear Ellipsometry.- 7.3.6 Raman Induced Kerr Effect Spectroscopy (RIKES).- 7.3.7 Optical Heterodyne Detected RIKES.- 7.3.8 Stimulated Raman Gain and Loss Spectroscopy.- 7.3.9 Four-Wave Mixing.- 7.3.10 Signals, Noise and Sensitivity.- 7.3.11 Signal Enhancement with Interferometers, Intra-Cavity Techniques and Multipass Cells.- 7.4 Applications.- 7.4.1 Combustion Diagnostics: Concentration and Temperature Measurement.- 7.4.2 Raman Cross Section and Nonlinear Susceptibility Measurements.- 7.4.3 High-Resolution Molecular Spectroscopy.- 7.4.4 Raman Spectra of Fluorescent and Resonant Samples.- 7.4.5 Polariton Dispersion: Spectroscopy in Momentum Space.- 7.4.6 Low Frequency Modes.- 7.4.7 Vibrational and Rotational Relaxation Measurements.- 7.5 Conclusions.- References.- Additional References with Titles.
TL;DR: A new iteration procedure for the Stark effect in hydrogen for any field strength is proposed in this article, which seems to be numerically accurate and the approximate explicit expression obtained for the ground state energy eigenvalue has analytic properties similar to those known for the exact solution.
TL;DR: A narrow-bandwidth (cw) phase-fluctuation laser-heterodyne interferometer for trace-gas detection is described and performance was evaluated using both Stark-effect modulation and conventional beam chopping.
Abstract: A narrow-bandwidth (cw) phase-fluctuation laser-heterodyne interferometer for trace-gas detection is described. Performance was evaluated using both Stark-effect modulation and conventional beam chopping. Sensitivities of 10−8 cm−1 were obtained in both cases. However, when Stark-effect modulation was employed, the usual background signal caused by interfering absorbing species and windows could be subtracted from the overall signal. In this mode, a detection limit of 5 parts in 109 (ppb) NH3 in air was obtained.
TL;DR: In this article, the Stark effect shift and splitting of 91 lines of neutral argon was studied, using electric field strengths of up to 700 kV cm-1, and the results were given in the form of coefficients which enable the calculation of the Stark shifts.
Abstract: In the spectral range between 4100 and 6800 A the Stark effect shift and splitting of 91 lines of neutral argon was studied, using electric field strengths of up to 700 kV cm-1. The investigations show that the behaviour of the lines can be interpreted as a shift and splitting of the upper levels of the lines. For these levels the results are given in the form of coefficients which enable the calculation of the Stark shifts.
TL;DR: In this paper, the levels n=4 of hydrogen atoms moving in a strong, uniform magnetic field BT, considering both the Zeeman effect and the translational Stark effect, were calculated for both Halpha and Hbeta, for arbitrary direction of observation and arbitrary particle velocity with respect to BT.
Abstract: Previous calculations by Isler (concerning the levels n=2 and n=3) (1976, 1977) are extended to include eigen-energies and eigenfunctions for the levels n=4 of hydrogen atoms moving in a strong, uniform magnetic field BT, considering both the Zeeman effect and the translational Stark effect. Emission line patterns are evaluated for both Halpha and Hbeta , for arbitrary direction of observation and arbitrary particle velocity with respect to BT. Finally, the emission line profiles for both lines are calculated for Maxwell distribution function of the radiating atoms, when the direction of observation is perpendicular to BT.
TL;DR: In this paper, the microwave spectrum of CH 3 OD has been observed in the frequency region between 14 and 92 GHz and rotational, torsional, and torsion-vibration-rotation interaction constants have been evaluated.
TL;DR: In this paper, 15 new CW FIR laser lines are reported from Stark tuned CO 2 optically pumped CH 3 OH and CH 3 OD, three with a CO 2 laser, and one with an N 2 O laser.
Abstract: Fifteen new CW FIR laser lines are reported from Stark tuned CO 2 optically pumped CH 3 OH and CH 3 OD. Four new CW laser lines have also been observed from zero field optically pumped CH 3 OD, three with a CO 2 laser, and one with an N 2 O laser.
TL;DR: Analytic relations between the Stark widths and shifts and the ionization potential of the corresponding emitters have been found and discussed in this article, where the authors also discussed the relationship between the two scales.
TL;DR: In this paper, a Kohn-Luttinger approach was used to estimate the speed of charge release associated with field ionization at sufficiently low temperatures, and it was found that charge release in the picosecond regime may be achievable in pre-breakdown fields in semiconductors.
Abstract: Using a Kohn‐Luttinger approach to shallow impurity levels in semiconductors, we estimate the speed of charge release associated with field ionization. At sufficiently low temperatures, this is predominantly a quantum‐mechanical process. It is found that charge release times in the picosecond regime may be achievable in prebreakdown fields in semiconductors. In GaAs, one picosecond release times correspond to fields of 0.2 V/μ and field energy densities of 2×10−18 J/μ3. In the picosecond regime, our estimates rely on published, mutually consistent Stark width results obtained by various techniques including dispersion relations and Weyl’s complex‐eigenvalue method.
TL;DR: In this paper, a Doppler-free optical double resonance spectroscopy (DOS) method was proposed for infrared-infrared double-resonance studies of the Stark effects of a variety of molecules.
Abstract: Principles and applications are described for a form of Doppler-free optical double resonance spectroscopy which uses amplitude modulation sidebands (v
L
±v) imposed on a single laser frequency (v
L
). The sidebands are generated by passing the carrier radiationv
L
through an electro-optic modulator, driven at a radiofrequency ν, which enables the intensity and polarization characteristics of the emerging radiation to be varied for enhancement of selected double-resonance processes. The technique has been applied to infrared-infrared double-resonance studies of the Stark effects of a variety of molecules—13CH3F,12CH3F, PH3,15NH3, GeH4, SiH4, and CH3D—for which physical results are presented and discussed. These results include determination of extremely small electric dipole moments (10−3–10−5 debye) for GeH4 and CH3D and, for the dipole moment of PH3, a vibrational state dependence which is extremely small (Δμ=0.0028(5) debye for ∣Δv
2∣=1) and a rotational state dependence which is of an unexpected sign. The spectra recorded in some cases display unusual polarization and optical saturation effects which deviate markedly from the predictions of a simple three-wave polarization theory.
TL;DR: In this paper, the laser, Raman, and hyper-Raman processes are studied in a three-wave four-level system by means of a numerical analysis of the steady-state density matrix equations.
Abstract: The laser, Raman, and hyper-Raman processes are studied in a three-wave four-level system by means of a numerical analysis of the steady-state density matrix equations. Gain spectra curves are presented for IR-IR and IR-MW pumped systems and for two four-level systems in NH 3 that yield 12.159 and 12.114 μm wavelength radiation. Using the gain spectra data, threshold pump intensities, output intensities, ac Stark shifts, M splittings, optimum NH 3 pressures, and saturation are studied. The theoretical data agrees with the experimental data well within a factor of two. It is shown that the hyper-Raman process can lead to higher power, frequency stable, optically pumped lasers.
TL;DR: In this article, the frequencies of 63 transitions in the ν 3 fundamental have been measured with a tunable sideband laser with the following excited state constants: ν 0 = 104861000 (44) cm −1, (A ′ − A ″) = −29377 (90) MHz; B = 25 197570 (20) MHz, D J = 5661 (22) kHz; D JK = 5216 (56) kHz, D K − K ″ K = −977 (70) kHz.
TL;DR: In this article, a quadruplet structure was observed both for zero and for non-zero detuning delta 2 of the probe beam in a double resonance experiment with a strong pump beam and a weak probe beam multiplet structures due to the AC Stark effect.
Abstract: In a double resonance experiment with a strong pump beam and a weak probe beam multiplet structures due to the AC Stark effect can be observed The authors report the first observation of such a multiplet in a three-level experiment The linearly polarised beams from a CW dye laser and a I2 stabilised He-Ne laser were counter-propagating in the neon discharge cell and the saturating laser frequency was tuned across the resonances The quadruplet structure was observed both for zero and for non-zero detuning delta 2 of the probe beam The corresponding calculations for the three-level system with degenerate levels have been performed using the density matrix formalism with a tensorial expansion of the matrix elements The theory includes the coupling of the various Zeeman sublevels by spontaneous emission and by the interaction with the two beams, and takes into account the finite value of the Doppler width
TL;DR: In this paper, a large aperture, wide field-of-view (FOV) modulator using the Stark effect in ammonia (NH3) is described. But the modulator configuration incorporates a longitudinal electric field produced between closely spaced, large diameter germanium windows.
Abstract: We describe the analysis, design, and construction of a large aperture, wide‐field‐of‐view modulator at 108 μm using the Stark effect in ammonia (NH3) The modulator configuration incorporates a longitudinal electric field produced between closely spaced, large‐diameter germanium windows The windows are antireflection coated for high transmission, and their relatively low resistivity allows their direct use as (transparent) Stark electrodes Enhanced modulation depth and improved electrical breakdown performance are obtained by using multiple interaction regions The modulator is mounted at the entrance aperture of a corner cube reflector, thus allowing two passes of the signal beam in a configuration which is retroreflecting and polarization insensitive This completed device has an aperture of 55 cm, a field of view of 38°, and a measured modulation depth of 25% at 14 MHz