Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Optics Letters

Transient self-diffraction in Nd:YAG saturable amplifiers

A. Brignon, Jean‐Pierre Huignard

Published Apr 1, 1994• 7 citations
Publisher

Abstract

We investigate self-diffraction and multiwave scattering by a nonsinusoidal gain grating induced in a thick laser medium with pulses of duration much less than the population relaxation time. The energies of the transmitted and of the two first-order self-diffracted beams are calculated. Experimental measurements performed in a flash-lamp-pumped Nd:YAG amplifier at lambda = 1.064 microm show good agreement with the theoretical results. A total energy in the two first-order scattered waves of 1.1 mJ is obtained for a total incident energy of 14 mJ.

DOI
10.1364/ol.19.000451

Related papers

Two-wave mixing in Nd:YAG by gain saturation

A. Brignon, Jean‐Pierre Huignard

Two-wave mixing at λ = 1.06 μm in the saturable gain of a flash-lamp-pumped Nd:YAG amplifier was investigated, both experimentally and theoretically, by development of a transient analysis. Despite the local response of the inverted medium, it is shown that energy redistribution can occur, thus leading to the depletion of a low-intensity signal beam. Finally we measured a diffraction efficiency of 20% of the transmission-gain grating by diffracting a probe beam at λ = 1.06 μm under the Bragg condition.

Optics Letters•Oct 1, 1993•42 citations

Transient analysis of degenerate four-wave mixing with orthogonally polarized pump beams in a saturable Nd:YAG amplifier

A. Brignon, Jean‐Pierre Huignard

Degenerate four-wave mixing with orthogonally polarized pump beams at /spl lambda/=1.06 /spl mu/m in the saturable gain of a flash-lamp-pumped Nd:YAG amplifier is investigated, both experimentally and theoretically, using pulses of duration much less than the population relaxation time. We introduce a new set of coupled-wave equations in this short pulse regime that includes the effect of the four interacting waves and the laser gain experienced by all the beams. The dependence of the efficiency of the process on the small-intensity-gain-length product, beam ratios, and fluences is analyzed. A reflectivity of a weak probe beam of 25 percent and a transmission-gain-grating diffraction efficiency of 32 percent are achieved. Finally, the temporal shape of the conjugate signal is studied for various gain-saturation regimes.>

IEEE Journal of Quantum Electronics•Jan 1, 1994•29 citations

Transient degenerate four-wave mixing in a saturable Nd:YAG amplifier: the effect of pump-beam propagation

A. Brignon, J. Raffy, Jean‐Pierre Huignard

A transient model of degenerate four-wave mixing in saturable amplifiers is developed for calculation of the phase-conjugate reflectivity in the weak-probe-beam limit. Our model takes into account the laser amplification of all the interacting beams together with the wave-mixing process between the two counterpropagating pump waves. Experimental investigations are made in a flash-lamp-pumped Nd:YAG amplifier with nanosecond pulses at 1.06 microm. A reflectivity of 22% is achieved when all the waves interfere within the laser medium.

Optics Letters•Jun 15, 1994•25 citations

Joint stimulated resonant backscattering of incoherent beams in Nd:YAG amplifier

A.S. Kuzhelev, Oleg L. Antipov, Sergey I. Belyaev

In our experiments a beam from a cw mul- tilongitudinal mode Nd:YAG-laser (at l .06 pm) was chopped to 30 ps pulse duration and split into two cross-polarized beams that were launched into two or three flash-lamp pumped Nd:YAG-rods. The optical paths of the split waves were different, so that the waves were mutually incoherent in the NdYAG amplifi- ers. These two beams co-propagated in the laser crystal. In the amplifiers we used NdYAG-crystals produced by method of horizontal-directed crystallization and having about a 1% concen- tration of the Nd-ions. The total logarithmic gain of the amplifiers for a weak signal ranged from 6 to 11. We measured the power of the backscat- tered beams at the resonant frequency with the same polarizations as those of each initial wave (Fig. 1). The SS effect of one beam depended on the presence ofthe other. The backscattered power in the presence of two initial beams was much more than that of one beam (Fig. 2). As we measured, the increase of the SS signals (with different polarizations) for two cross- polarized waves was not caused by depolariza- tion in the NdYAG amplifier (curve 3 in Fig. 2). The case when one initial wave was much less than the other was considered. We ob- served that the weak beam, with negligible SS, scattered on the grating induced by the other strong cross-polarized wave and its scattering wave. In fact, we tested the scattering grating, induced by the strong initial wave and the scat- tering wave, using the weak signal. These facts showed that the simultaneous scattering was realized by joint scattering grat- ing. Each of the two pairs (the initial waves E:fl, E:, and the backscattering waves E:, E:, in Fig. 1) induced their own grating of population. The separate changes ofpopulation were sum- marized to give the joint scattering grating. So,

Conference on Lasers and Electro-Optics•Aug 24, 2005•0 citations

Self-diffraction in population gratings

H. L. Fragnito, Silvania F. Pereira, Alvin E. Kiel

We present a nonperturbative theory of self-diffraction in thick, pseudostationary population gratings induced by the interference of two nearly collinear incident laser beams of arbitrary relative and absolute intensities. At large saturation parameters, the grating becomes nonsinusoidal, and high-order diffraction occurs efficiently. We obtain an exact expression for the Fourier coefficients of the grating that significantly simplifies the interpretation of the various coherent coupling mechanisms and permits efficient computer simulations. In the case of small depletion of the pump waves, we obtain simple analytic expressions for the scattered intensity into any order of self-diffraction. We present our results in a manner that should aid an experimenter in choosing the optical thickness of the unsaturated medium and the sum and ratio of the pump intensities to obtain optimum diffraction intensity in a given order.

Journal of the Optical Society of America B•Aug 1, 1987•25 citations

Resonant two-wave mixing of optical beams by refractive-index and gain gratings in inverted Nd:YAG

Oleg L. Antipov, Sergey I. Belyaev, A.S. Kuzhelev +1 more

It is shown experimentally that a weak optical signal in a Nd:YAG amplifier can have an extraordinarily large gain that is due to transient coherent nonlinear interaction with a strong laser beam. The effect is explained by the diffraction of the strong beam on the dynamic refractive-index grating induced in the interference field of the interacting optical waves and caused by the difference of polarizability of the excited and the unexcited Nd3+ ions. The numerical calculation confirmed the energy transfer from the strong beam to the weak one owing to the predominance of diffraction efficiency of the refractive-index grating over the gain grating in an inverted laser crystal. The investigations give the estimation of the ratio of the real and the imaginary parts of the resonant susceptibility of Nd:YAG at 1064 nm in the range 2–3.

Journal of the Optical Society of America B•Aug 1, 1998•22 citations
We investigate self-diffraction and multiwave scattering by a nonsinusoidal gain grating induced in a thick laser medium with pulses of duration much less than the population relaxation time. The energies of the transmitted and of the two first-order self-diffracted beams are calculated. Experimental measurements performed in a flash-lamp-pumped Nd:YAG amplifier at lambda = 1.064 microm show good agreement with the theoretical results. A total energy in the two first-order scattered waves of 1.1 mJ is obtained for a total incident energy of 14 mJ.
Two-wave mixing at λ = 1.06 μm in the saturable gain of a flash-lamp-pumped Nd:YAG amplifier was investigated, both experimentally and theoretically, by development of a transient analysis. Despite the local response of the inverted medium, it is shown that energy redistribution can occur, thus leading to the depletion of a low-intensity signal beam. Finally we measured a diffraction efficiency of 20% of the transmission-gain grating by diffracting a probe beam at λ = 1.06 μm under the Bragg condition.
Degenerate four-wave mixing with orthogonally polarized pump beams at /spl lambda/=1.06 /spl mu/m in the saturable gain of a flash-lamp-pumped Nd:YAG amplifier is investigated, both experimentally and theoretically, using pulses of duration much less than the population relaxation time. We introduce a new set of coupled-wave equations in this short pulse regime that includes the effect of the four interacting waves and the laser gain experienced by all the beams. The dependence of the efficiency of the process on the small-intensity-gain-length product, beam ratios, and fluences is analyzed. A reflectivity of a weak probe beam of 25 percent and a transmission-gain-grating diffraction efficiency of 32 percent are achieved. Finally, the temporal shape of the conjugate signal is studied for various gain-saturation regimes.>
A transient model of degenerate four-wave mixing in saturable amplifiers is developed for calculation of the phase-conjugate reflectivity in the weak-probe-beam limit. Our model takes into account the laser amplification of all the interacting beams together with the wave-mixing process between the two counterpropagating pump waves. Experimental investigations are made in a flash-lamp-pumped Nd:YAG amplifier with nanosecond pulses at 1.06 microm. A reflectivity of 22% is achieved when all the waves interfere within the laser medium.
In our experiments a beam from a cw mul- tilongitudinal mode Nd:YAG-laser (at l .06 pm) was chopped to 30 ps pulse duration and split into two cross-polarized beams that were launched into two or three flash-lamp pumped Nd:YAG-rods. The optical paths of the split waves were different, so that the waves were mutually incoherent in the NdYAG amplifi- ers. These two beams co-propagated in the laser crystal. In the amplifiers we used NdYAG-crystals produced by method of horizontal-directed crystallization and having about a 1% concen- tration of the Nd-ions. The total logarithmic gain of the amplifiers for a weak signal ranged from 6 to 11. We measured the power of the backscat- tered beams at the resonant frequency with the same polarizations as those of each initial wave (Fig. 1). The SS effect of one beam depended on the presence ofthe other. The backscattered power in the presence of two initial beams was much more than that of one beam (Fig. 2). As we measured, the increase of the SS signals (with different polarizations) for two cross- polarized waves was not caused by depolariza- tion in the NdYAG amplifier (curve 3 in Fig. 2). The case when one initial wave was much less than the other was considered. We ob- served that the weak beam, with negligible SS, scattered on the grating induced by the other strong cross-polarized wave and its scattering wave. In fact, we tested the scattering grating, induced by the strong initial wave and the scat- tering wave, using the weak signal. These facts showed that the simultaneous scattering was realized by joint scattering grat- ing. Each of the two pairs (the initial waves E:fl, E:, and the backscattering waves E:, E:, in Fig. 1) induced their own grating of population. The separate changes ofpopulation were sum- marized to give the joint scattering grating. So,
We present a nonperturbative theory of self-diffraction in thick, pseudostationary population gratings induced by the interference of two nearly collinear incident laser beams of arbitrary relative and absolute intensities. At large saturation parameters, the grating becomes nonsinusoidal, and high-order diffraction occurs efficiently. We obtain an exact expression for the Fourier coefficients of the grating that significantly simplifies the interpretation of the various coherent coupling mechanisms and permits efficient computer simulations. In the case of small depletion of the pump waves, we obtain simple analytic expressions for the scattered intensity into any order of self-diffraction. We present our results in a manner that should aid an experimenter in choosing the optical thickness of the unsaturated medium and the sum and ratio of the pump intensities to obtain optimum diffraction intensity in a given order.
It is shown experimentally that a weak optical signal in a Nd:YAG amplifier can have an extraordinarily large gain that is due to transient coherent nonlinear interaction with a strong laser beam. The effect is explained by the diffraction of the strong beam on the dynamic refractive-index grating induced in the interference field of the interacting optical waves and caused by the difference of polarizability of the excited and the unexcited Nd3+ ions. The numerical calculation confirmed the energy transfer from the strong beam to the weak one owing to the predominance of diffraction efficiency of the refractive-index grating over the gain grating in an inverted laser crystal. The investigations give the estimation of the ratio of the real and the imaginary parts of the resonant susceptibility of Nd:YAG at 1064 nm in the range 2–3.