The amplitude fluctuations in a single-mode laser for the case of regular pumping when the atoms ... more The amplitude fluctuations in a single-mode laser for the case of regular pumping when the atoms are injected in the cavity at fixed, unfluctuating rate are discussed. The dressed atom approach is employed. A comparison is made of such pumping scheme with the conventional one, when the number of active atoms is fixed. The results of the present work agree
ICONO '95: Fundamentals of Laser-Matter Interaction, 1996
ABSTRACT A dielectric microsphere possesses natural modes of oscillation at characteristic freque... more ABSTRACT A dielectric microsphere possesses natural modes of oscillation at characteristic frequencies, corresponding to specific size to wavelength ratios. These structure resonances are known to cause extremely large field intensities and have extremely high quality. We investigate here systematically the characteristic equation, defining the natural frequencies, as a function of the change in the asymptotic behavior of spherical Bessel functions which reveals the fact that there exists resonances with very narrow linewidth. This characteristic has very important implications to nonlinear optics.
A new principle of laser coherence found recently provides an example of the most correlated quan... more A new principle of laser coherence found recently provides an example of the most correlated quantum state. We discuss the relation between squeezing phenomena and quantum correlations (QC). These new results can be understood only in the framework of a special QC approach.
An explicit relationship between the Lorenz-Mie resonances and nonlinear optics of a microsphere ... more An explicit relationship between the Lorenz-Mie resonances and nonlinear optics of a microsphere has been found. We have constructed an approximate analytic method which allows an adequate assessment of the threshold for stimulated Raman scattering in microspheres. Systematic investigation of the characteristic equation, using approximate analytic expressions, reveals that not all modes have the same quality. Some resonances with very high quality correspond to a physical situation in which the spherical waves can be envisioned as whispering-gallery light waves that are totally internally reflected by the sphere boundary, without suffering almost any loss.
Conditions for noise minimization in laser systems are studied and formulated as a principle. It ... more Conditions for noise minimization in laser systems are studied and formulated as a principle. It in- volves the correlation of the internal degrees of freedom of the system and the relative rates of transi- tions between them. The minimization principle proposed is appropriate for a variety of lasing schemes including nonunidirectional pump processes. It allows one to interpret a wide scope of experimental re- sults. It is expected to be serviceable in further exploring of the squeezing phenomenon.
Atomic and Quantum Optics: High-Precision Measurements, 1996
The most important mechanism to occur in biological distributed sensory networks (DSNs) is called... more The most important mechanism to occur in biological distributed sensory networks (DSNs) is called lateral inhibition, (LI). LI relies on one simple principle. Each sensor strives to suppress its neighbors in proportion to its own excitation. In this study, LI mechanism is exploited to localize the unknown position of a light source that illuminated the photosensitive sensory network containing high and low quality sensors. Each photosensitive sensor was then calibrated to accurately read the distance to the light source. A series of experiments were conducted employing both quality sensors. Low quality array was allowed to take advantage of LI, whereas the high quality one was not. Results showed that the lateral inhibition mechanism increased the sensitivity of inferior quality sensors, giving the ability to make the localization as sensitive as high quality sensors do. This suggests that the networks with multitude of sensors could be made cost-effective, were these sensory networks equipped with LI.
The conventional way of studying laser noise assumes analytic solution of the quantum problem for... more The conventional way of studying laser noise assumes analytic solution of the quantum problem for the laser field coupled to the active medium. A number of the laser schemes have been discussed, and predictions for noise reduction and for the squeezed state of field have been made.1 On the basis of first principies of the quantum mechanies, the conventional approach exhibits the relatively rare situation in which the quantum equations admit compact analytic solution. At the same time, the difficulty in interpreting the results seems to be unresolved. Specifically, it is very difficult lo determine the relative contribution of each physical source of noise to the final fluctuation result.
Autodyne lidar with CO2-laser is a good system for remote measurements of environmental gases 1 a... more Autodyne lidar with CO2-laser is a good system for remote measurements of environmental gases 1 as a number of them have absorption bands in spectral region 9-11 km. In this report we present an analytical approach for calculation of the parameters of a parametric autodyne lidar for environmental DIAL applications. This approach allows one to express analytically the parameters of the atmosphere, such as the absorption coefficient and the distance to remote target, through experimentally measured values. A model of parametric autodyne lidar based on two level laser scheme has been considered. The aim is to derive analytical dependencies of lidar field on parameters of the atmosphere. Two nonlinear differential equations for laser field amplitude at resonator mirrors are derived. Using reflectivity of the remote mirror as a small parameter (it can reach 10i 9 in field experiments) a perturbation theory has been built, which allows one to reduce nonlinear lidar equations to a couple o...
Technical Digest. Summaries of Papers Presented at the International Quantum Electronics Conference. Conference Edition. 1998 Technical Digest Series, Vol.7 (IEEE Cat. No.98CH36236), 1998
The behavior of a laser intensity as a function of a pump rate is studied. We consider a three-le... more The behavior of a laser intensity as a function of a pump rate is studied. We consider a three-level lasing scheme with two different types of pumping. In the first case, the lower lasing level is depleted to the ground state, and then the pumping is used to excite the atom from the ground state to the upper lasing level. In the second case the pumping is used to excite the atom directly from the lower lasing level to one of the excited states, which is then depleted to the upper lasing level. We refer these two types of pumping as type 1 and type 2, respectively. It is shown that although these two schemes are equivalent mathematically, i.e., they are formally described by the same set of equations, physically their dynamical properties are completely different. It is noted that the pumping of the type 1 does not affect either of lasing levels directly, whereas the pumping of the type 2 does connect the lower lasing level with one of the excited states. It is this difference of the two ways of pumping which is responsible for the crucial difference in the dynamic behavior of the lasing schemes of types 1 and 2
Optica Acta: International Journal of Optics, 1983
The present paper considers a model of a single-mode laser based on two-level atoms having transl... more The present paper considers a model of a single-mode laser based on two-level atoms having translational degrees of freedom. Correlation of the field and the atomic motion due to the recoil effect is taken into account. The self-consistent theory describing dynamic properties of the system is performed on the basis of semiclassical approximation. It is shown that due to the
We suggest an approach to study hierarchy, especially hidden one, of complex networks based on th... more We suggest an approach to study hierarchy, especially hidden one, of complex networks based on the analysis of their vulnerability. Two quantities are proposed as a measure of network hierarchy. The first one is the system vulnerability V. We show that being quite suitable for regular networks this characteristic does not allow one to estimate the hierarchy of large random networks. The second quantity is a relative variance h of the system vulnerability that allows us to characterize a "natural" hierarchy level of random networks. We find that hierarchical properties of random networks depend crucially on a ratio between the number of nodes and the number of edges. We note that any graph with a transitive isometry group action (i.e. an absolutely symmetric graph) is not hierarchical. Breaking such a symmetry leads to appearance of hierarchy.
A new version of the projection operator is proposed that allows its application area to be exten... more A new version of the projection operator is proposed that allows its application area to be extended, including a general treatment ofnonequiibrium subsystems. The modified operator form is used as a means of separating the subsystem variables. The given app~oach furnishes a simple recipe forthe derivation ofthe dynamic equations and the closed master equation. An example ofthe op~rator application to the quantum laser theory is considered.
It is shown that a three-level laser can become the first example of an optically active system t... more It is shown that a three-level laser can become the first example of an optically active system to generate a squeezed-field state.
The amplitude fluctuations in a single-mode laser for the case of regular pumping when the atoms ... more The amplitude fluctuations in a single-mode laser for the case of regular pumping when the atoms are injected in the cavity at fixed, unfluctuating rate are discussed. The dressed atom approach is employed. A comparison is made of such pumping scheme with the conventional one, when the number of active atoms is fixed. The results of the present work agree
ICONO '95: Fundamentals of Laser-Matter Interaction, 1996
ABSTRACT A dielectric microsphere possesses natural modes of oscillation at characteristic freque... more ABSTRACT A dielectric microsphere possesses natural modes of oscillation at characteristic frequencies, corresponding to specific size to wavelength ratios. These structure resonances are known to cause extremely large field intensities and have extremely high quality. We investigate here systematically the characteristic equation, defining the natural frequencies, as a function of the change in the asymptotic behavior of spherical Bessel functions which reveals the fact that there exists resonances with very narrow linewidth. This characteristic has very important implications to nonlinear optics.
A new principle of laser coherence found recently provides an example of the most correlated quan... more A new principle of laser coherence found recently provides an example of the most correlated quantum state. We discuss the relation between squeezing phenomena and quantum correlations (QC). These new results can be understood only in the framework of a special QC approach.
An explicit relationship between the Lorenz-Mie resonances and nonlinear optics of a microsphere ... more An explicit relationship between the Lorenz-Mie resonances and nonlinear optics of a microsphere has been found. We have constructed an approximate analytic method which allows an adequate assessment of the threshold for stimulated Raman scattering in microspheres. Systematic investigation of the characteristic equation, using approximate analytic expressions, reveals that not all modes have the same quality. Some resonances with very high quality correspond to a physical situation in which the spherical waves can be envisioned as whispering-gallery light waves that are totally internally reflected by the sphere boundary, without suffering almost any loss.
Conditions for noise minimization in laser systems are studied and formulated as a principle. It ... more Conditions for noise minimization in laser systems are studied and formulated as a principle. It in- volves the correlation of the internal degrees of freedom of the system and the relative rates of transi- tions between them. The minimization principle proposed is appropriate for a variety of lasing schemes including nonunidirectional pump processes. It allows one to interpret a wide scope of experimental re- sults. It is expected to be serviceable in further exploring of the squeezing phenomenon.
Atomic and Quantum Optics: High-Precision Measurements, 1996
The most important mechanism to occur in biological distributed sensory networks (DSNs) is called... more The most important mechanism to occur in biological distributed sensory networks (DSNs) is called lateral inhibition, (LI). LI relies on one simple principle. Each sensor strives to suppress its neighbors in proportion to its own excitation. In this study, LI mechanism is exploited to localize the unknown position of a light source that illuminated the photosensitive sensory network containing high and low quality sensors. Each photosensitive sensor was then calibrated to accurately read the distance to the light source. A series of experiments were conducted employing both quality sensors. Low quality array was allowed to take advantage of LI, whereas the high quality one was not. Results showed that the lateral inhibition mechanism increased the sensitivity of inferior quality sensors, giving the ability to make the localization as sensitive as high quality sensors do. This suggests that the networks with multitude of sensors could be made cost-effective, were these sensory networks equipped with LI.
The conventional way of studying laser noise assumes analytic solution of the quantum problem for... more The conventional way of studying laser noise assumes analytic solution of the quantum problem for the laser field coupled to the active medium. A number of the laser schemes have been discussed, and predictions for noise reduction and for the squeezed state of field have been made.1 On the basis of first principies of the quantum mechanies, the conventional approach exhibits the relatively rare situation in which the quantum equations admit compact analytic solution. At the same time, the difficulty in interpreting the results seems to be unresolved. Specifically, it is very difficult lo determine the relative contribution of each physical source of noise to the final fluctuation result.
Autodyne lidar with CO2-laser is a good system for remote measurements of environmental gases 1 a... more Autodyne lidar with CO2-laser is a good system for remote measurements of environmental gases 1 as a number of them have absorption bands in spectral region 9-11 km. In this report we present an analytical approach for calculation of the parameters of a parametric autodyne lidar for environmental DIAL applications. This approach allows one to express analytically the parameters of the atmosphere, such as the absorption coefficient and the distance to remote target, through experimentally measured values. A model of parametric autodyne lidar based on two level laser scheme has been considered. The aim is to derive analytical dependencies of lidar field on parameters of the atmosphere. Two nonlinear differential equations for laser field amplitude at resonator mirrors are derived. Using reflectivity of the remote mirror as a small parameter (it can reach 10i 9 in field experiments) a perturbation theory has been built, which allows one to reduce nonlinear lidar equations to a couple o...
Technical Digest. Summaries of Papers Presented at the International Quantum Electronics Conference. Conference Edition. 1998 Technical Digest Series, Vol.7 (IEEE Cat. No.98CH36236), 1998
The behavior of a laser intensity as a function of a pump rate is studied. We consider a three-le... more The behavior of a laser intensity as a function of a pump rate is studied. We consider a three-level lasing scheme with two different types of pumping. In the first case, the lower lasing level is depleted to the ground state, and then the pumping is used to excite the atom from the ground state to the upper lasing level. In the second case the pumping is used to excite the atom directly from the lower lasing level to one of the excited states, which is then depleted to the upper lasing level. We refer these two types of pumping as type 1 and type 2, respectively. It is shown that although these two schemes are equivalent mathematically, i.e., they are formally described by the same set of equations, physically their dynamical properties are completely different. It is noted that the pumping of the type 1 does not affect either of lasing levels directly, whereas the pumping of the type 2 does connect the lower lasing level with one of the excited states. It is this difference of the two ways of pumping which is responsible for the crucial difference in the dynamic behavior of the lasing schemes of types 1 and 2
Optica Acta: International Journal of Optics, 1983
The present paper considers a model of a single-mode laser based on two-level atoms having transl... more The present paper considers a model of a single-mode laser based on two-level atoms having translational degrees of freedom. Correlation of the field and the atomic motion due to the recoil effect is taken into account. The self-consistent theory describing dynamic properties of the system is performed on the basis of semiclassical approximation. It is shown that due to the
We suggest an approach to study hierarchy, especially hidden one, of complex networks based on th... more We suggest an approach to study hierarchy, especially hidden one, of complex networks based on the analysis of their vulnerability. Two quantities are proposed as a measure of network hierarchy. The first one is the system vulnerability V. We show that being quite suitable for regular networks this characteristic does not allow one to estimate the hierarchy of large random networks. The second quantity is a relative variance h of the system vulnerability that allows us to characterize a "natural" hierarchy level of random networks. We find that hierarchical properties of random networks depend crucially on a ratio between the number of nodes and the number of edges. We note that any graph with a transitive isometry group action (i.e. an absolutely symmetric graph) is not hierarchical. Breaking such a symmetry leads to appearance of hierarchy.
A new version of the projection operator is proposed that allows its application area to be exten... more A new version of the projection operator is proposed that allows its application area to be extended, including a general treatment ofnonequiibrium subsystems. The modified operator form is used as a means of separating the subsystem variables. The given app~oach furnishes a simple recipe forthe derivation ofthe dynamic equations and the closed master equation. An example ofthe op~rator application to the quantum laser theory is considered.
It is shown that a three-level laser can become the first example of an optically active system t... more It is shown that a three-level laser can become the first example of an optically active system to generate a squeezed-field state.
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Papers by G. Koganov