Showing papers on "Four-wave mixing published in 1979"
TL;DR: It is proposed that the process of nonlinear optical phase conjugation can be utilized to compensate for channel dispersion and hence to correct for temporal pulse broadening.
Abstract: It is proposed that the process of nonlinear optical phase conjugation can be utilized to compensate for channel dispersion and hence to correct for temporal pulse broadening. Specifically, a four-wave nonlinear interaction is shown to achieve pulse renarrowing. Spectral bandwidth constraints of the input pulse are presented for typical phase-conjugate interaction parameters.
447 citations
TL;DR: Numerical estimates indicate that the generation and detection of TCS light via degenerate four-wave mixing and homodyne detection can be accomplished with current technology.
Abstract: It is shown that degenerate four-wave mixing generates two-photon coherent states (TCS) of the radiation field for modes that are proper combinations of the output object and image waves. TCS light has novel quantum behavior, which can be probed by homodyne detection, intensity interferometry, or photocount statistics. Numerical estimates indicate that the generation and detection of TCS light via degenerate four-wave mixing and homodyne detection can be accomplished with current technology.
260 citations
Journal Article•
TL;DR: Nondegenerate four-wave mixing is demonstrated in Ti in-diffused lithium niobate waveguides and the second-order nonlinear interaction between two oppositely propagating guided modes was observed to generate a radiation field into a direction perpendicular to the surface during the overlap of the incident waves.
Abstract: Nondegenerate four-wave mixing is demonstrated in Ti in-diffused lithium niobate waveguides. The second-order nonlinear interaction between two oppositely propagating guided modes was observed to generate a radiation field at the sum frequency into a direction perpendicular to the surface during the overlap of the incident waves.
81 citations
TL;DR: In this paper, the second-order nonlinear interaction between two oppositely propagating guided modes was observed to generate a radiation field at the sum frequency into a direction perpendicular to the surface during the overlap of the incident waves.
Abstract: Nondegenerate four-wave mixing is demonstrated in Ti in-diffused lithium niobate waveguides. The second-order nonlinear interaction between two oppositely propagating guided modes was observed to generate a radiation field at the sum frequency into a direction perpendicular to the surface during the overlap of the incident waves.
79 citations
TL;DR: In this paper, the degenerate three-wave and four-wave phase conjugation was generalized to include signal-pump detuning and the theory is an extension of grating-dip spectroscopy.
Abstract: The formulations of degenerate three-wave and four-wave phase conjugation are generalized to include signal-pump detuning The theory is an extension of grating-dip spectroscopy The reflection bandpass is shown to be limited by the power-broadened bandwidth (∝1/T1) of the two-level population difference Unlike for running-wave saturation, the signal-absorption coefficient saturated by a standing wave shows virtually no gain regions
65 citations
TL;DR: A method is introduced that measures the spatial-migration rate of electronic excitation in condensed media over distances of the order of 0.1 microm, and upper limits are placed on the diffusion constants in pink ruby and Nd(3+)-doped silicate glass.
Abstract: A method is introduced that measures the spatial-migration rate of electronic excitation in condensed media over distances of the order of 0.1 μm. Two volume holographic gratings of widely differing modulation periods are simultaneously produced, using a phase-conjugate wave geometry of degenerate four-wave mixing. Spatial migration results in a reduced scattering efficiency of one grating and is observed as a polarization rotation of the backward-going output wave. Upper limits are placed on the diffusion constants in pink ruby and Nd3+-doped silicate glass.
55 citations
TL;DR: In this article, phase-conjugate reflection and amplification with an effective reflectivity exceeding unity was obtained by redirecting the output of a TEA CO(2)-laser oscillator into its own gain medium.
Abstract: We have obtained phase-conjugate reflection and amplification with an effective reflectivity exceeding unity by redirecting the output of a TEA CO(2)-laser oscillator into its own gain medium. The intense counterpropagating waves within the laser were coupled through the saturated medium to provide the nonlinearity in a process analogous to degenerate four-wave mixing.
55 citations
TL;DR: A calculation, which includes such effects from the beginning, of the small-signal phase-conjugate-reflection coefficient for both Doppler-broadened and homogeneously broadened resonant transitions is summarized.
Abstract: In current experiments studying cw optical-wavefront conjugation by degenerate four-wave mixing, the effects of atomic motion are not negligible. I summarize a calculation, which includes such effects from the beginning, of the small-signal phase-conjugate-reflection coefficient for both Doppler-broadened and homogeneously broadened resonant transitions.
54 citations
TL;DR: Numerical estimates of the nonlinear susceptibility show that relatively large signals can be produced easily without significant problems from competing physical phenomena such as self-focusing or stimulated Brillouin and Raman scattering.
Abstract: We report an analysis of degenerate four-wave mixing in uniform plasmas and show that the magnitude of the third-order susceptibility (varying as lambda(2)) can be comparable to (10(-11) esu for lambda = 10.6 microm) or orders of magnitude larger (10(-3) esu for lambda= 10 cm) than the corresponding susceptibility in typical nonlinear materials. The nonlinear contribution to the macroscopic current resulting from the ponderomotive force is generated from the two-component fluid model by means of a linearized perturbation scheme. Numerical estimates of the nonlinear susceptibility show that relatively large signals can be produced easily without significant problems from competing physical phenomena such as self-focusing or stimulated Brillouin and Raman scattering.
47 citations
TL;DR: In this paper, a temperature-dependent Sellmeier equation for four-wave mixing in a material like Ge is calculated and the average power limit for the case where one wave vector is fixed and two wave vectors are fixed.
Abstract: A temperature-dependent Sellmeier equation is calculated for Ge. The accuracy of this temperature-dependent Sellmeier equation is compared with the internal consistency of the data. The phase-matching condition is discussed for four-wave mixing when two of the wave vectors are equal. The average power limit for four-wave mixing in a material like Ge is derived both for the case where one wave vector is fixed and for the case where two wave vectors are fixed. Using the derived Sellmeier equation, the average power limit for the four-wave mixing is calulated.
46 citations
TL;DR: In this article, the degenerate four-wave mixing of 1.06-μm laser radiation in silicon was investigated using a Q-switched Nd:YAG laser at intensities of 6.8 MW/cm2.
Abstract: We report detailed experimental results on degenerate four-wave mixing of 1.06-μm laser radiation in silicon. Using ~100-mJ pump pulses of 15-nsec duration from a Q-switched Nd:YAG laser at intensities of ~6.8 MW/cm2, we obtained an energy conversion of over 150% for the probe-to-signal reflection.
TL;DR: In this paper, it was shown that the nonlinear electric polarization density that is third order in the propagating electric fields in the guide medium generates the replica by the process of four-wave mixing.
Abstract: We show that one can generate the time-reversed replica of an "input" monochromatic, image-bearing beam by coupling it into a waveguide where it interacts with counterpropagating multimode "pump" waves of the same frequency. The nonlinear electric polarization density that is third order in the propagating electric fields in the guide medium generates the replica by the process of "four-wave mixing." We show also that the input beam can serve simultaneously as its own pump beam. If the frequency ν of the backward pump beam is different from the frequency ω to of the input beam, then the "phase-conjugate" to the input is generated at the entrance plane to the guide, and this radiates a replica of the input field, magnified by \omega/
u , back along the input beam. The pump power required per resolution element to phase-conjugate a beam in a waveguide is orders-of-magnitude less than for the corresponding process with free (unguided) waves interacting in an infinite medium. Unlike the requirements for free waves, the pump waves do not need to be well aligned or single-mode to produce high fidelity in the replication process. Neither does the guiding structure or enclosed medium have to be precise in dimension or uniformity; the main requirements on the guiding structure being that it not attenuate the waves too heavily. Formulas are derived for the replication efficiency and fidelity in the various guided configurations. We also show how the process can be used: 1) to make a narrowband optical filter with a large acceptance solid angle; 2) to perform image-frequency conversion; 3) to obtain Raman and two-photon spectra of small samples; and 4) to achieve broadband optical amplification. We examine the conditions under which phase conjugation and these applications can be performed at several frequencies simultaneously. Limitations placed by the power-dependence of propagation constants are derived.
TL;DR: In this article, the dispersion-free point associated with a pair of adjacent doublet transitions in atomic and molecular systems is used to observe enormous pulse amplification of a phase-conjugated wavefront and intense visible oscillation without mirror feedback in the degenerate four-wave parametric mixing in sodium vapor doublet at the characteristic wavelength of 5894 A.
Abstract: This paper presents theoretical and experimental descriptions of a novel application of the dispersion-free point associated with a pair of adjacent doublet transitions in atomic and molecular systems. At this point it is possible to observe enormous pulse amplification of a phase-conjugated wavefront and intense visible oscillation without mirror feedback in the degenerate four-wave parametric mixing in sodium vapor doublet at the characteristic wavelength of 5894 A. At the dispersion-free point one also observes an ac Stark-free condition which permits the generation of a new type of coherent optical radiation called "cooperative phased-array radiation" (COPAR) from a phased-array system of coherently excited atoms in the medium at the wavelength.
TL;DR: The observation of cw backward-wave generation using degenerate four-wave mixing in a nonresonant medium with a pump power of only 6 mW has been observed, in reasonable agreement with theoretical predictions.
Abstract: We report on the observation of cw backward-wave generation using degenerate four-wave mixing in a nonresonant medium. The interaction took place inside a 3-m-long CS2-filled 4-µm i.d. optical fiber. With a pump power of only 6 mW inside the fiber, a backward-wave conversion efficiency of 0.45% has been observed, which is in reasonable agreement with theoretical predictions.
01 Jan 1979
TL;DR: The general framework for describing the large variety of nonlinear optical phenomena caused by an electric polarization cubic in the electric field amplitudes is described in this article. But this framework is not suitable for the case of optical optical phenomena.
Abstract: The general framework for describing the large variety of nonlinear optical phenomena caused by an electric polarization cubic in the electric field amplitudes.
TL;DR: In this article, the authors considered the limitations of two-photon-resonant frequency up-conversion due to quadratic Kerr effect, twophoton absorption, and Raman scattering.
Abstract: This paper considers the limitations of (near) two-photon-resonant frequency up-conversion due to quadratic Kerr effect, two-photon absorption, and Raman scattering. These processes, which are intimately tied to the four-wave mixing process, limit the efficiency and/or the pulse length due to breaking of phase-matching, attenuation, and (de)focusing. General expressions are derived for the limits on the efficiency and the pulse length resulting from these processes. The results of the theoretical analysis are applied to three examples of great practical interest; i.e., tripling of the CO 2 laser in liquid CO, mixing of IR photons using vibrational nonlinearities, and IR image up-conversion in alkali metal vapors. Several new, important properties of these systems are derived.
TL;DR: In this article, the problem of transient four-wave mixing with non-coincident optical pulses is analyzed using the formalism of the time evolution and the density matrix operators.
Abstract: The problem of transient four-wave mixing with noncoincident optical pulses is analyzed using the formalism of the time evolution and the density matrix operators. The results are relevant to problems involving real time holography and wave conjugation. The treatment establishes a bridge between the conventional formalisms of nonlinear optics and of photon echoes.
TL;DR: Results indicate that beryllium will be an efficient nonlinear medium in this spectral region with improvements to the stability of the furnace to allow phase matching and operation at higher pressures.
Abstract: Radiation was generated between 1210 and 1230 A by four-wave sum mixing in beryllium vapor where the 2s(2)(1)S-2s3d(1)D transition was two-photon resonant. Results indicate that beryllium will be an efficient nonlinear medium in this spectral region with improvements to the stability of the furnace to allow phase matching and operation at higher pressures.
TL;DR: In this paper, the authors proposed a phase conjugation method to generate a time-reversed replica of an incident wave in real time without the need for intermediate electronics, and with amplification if desired, using nonlinear optical mixing.
Abstract: A new research area in coherent optics has emerged and has been receiving increasing attention from many scientists as its important applications are recognized. Phase conjugate optics is the name which seems to have attached itself to this new field. The main feature of phase conjugate optics is the generation of an electromagnetic wave with a phase distribution which is, at each point in space, the reversal of that of an arbitrary incoming monochromatic wave. The wavefront, after being generated, proceeds to propagate in the opposite direction, retracing in reverse the path of the incoming wave. Thus, the phase reversal or conjugation process results in what is frequently called a time-reversed replica of the incident wave. If we consider, as an example, an incoming spherical wavefront which, diverging from a point, has a radius of curvature R, its conjugate-replica will be an outgoing spherical wavefront converging toward the same point and with a radius of curvature -R. Phase conjugation techniques have been used in the past for imaging through phase distorting media; well known examples can be found in holography [1] and adaptive optical systems [2]. The new and attractive feature, which differentiates phase conjugate optics from the previous techniques, is the use of nonlinear optical mixing to generate in real time without the need for intermediate electronics, and with amplification if desired, a time-reversed replica of an incident wave.
TL;DR: In this article, a strong resonance in the third order nonlinear optical susceptibility of n-type silicon corresponding to the valley orbit splitting of the 1s-states of phoshorous and antimony donors was observed.
01 Jan 1979
TL;DR: The third-order nonlinear susceptibility of Germanium enables two incident laser beams (υ 1, υ 2 wavenumbers) to generate combination frequencies υ3 = 2υ1 - υ2, σ 4 = 2 σ2 - σ 1∘ √ σ 2 as mentioned in this paper.
Abstract: The third-order nonlinear susceptibility [1] of Germanium enables two incident laser beams (υ1, υ2 wavenumbers) to generate combination frequencies υ3 = 2υ1 - υ2, υ4 = 2υ2 - υ1∘ Two efficient and powerful gas lasers (CO2, NH3), operating between 900 and 1100 cm-1 (υ1) and near 780 cm-1 (υ2) respectively, enable combination frequencies to be generated in the photochemically important regions 1420 - 1020 cm-1 (υ3) and 660 - 460 cm-1 (υ4). Such mixing can be phase-matched in room temperature Germanium if the incident laser beams υ1 υ2 are very slightly inclined at an angle θ (inside the crystal) (Fig. 1). Also shown in Fig. 1 are multiphonon absorption coefficients for Germanium at various temperatures.
TL;DR: In this paper, a tunable infra-red generation from 7-22 μm by non-collinear phase matched four-wave mixing in room temperature germanium is discussed and demonstrated for selected frequencies across this range.
Abstract: Tunable infra-red generation from 7–22 μm by non-collinear phase matched four-wave mixing in room temperature germanium is discussed and demonstrated for selected frequencies across this range. Scaling and optimization of the system should yield output powers of a few hundred kWs, particularly useful at ≈ 16 μm for isotopic enrichment of UF6.