Showing papers by "Dmitry Strekalov published in 2007"
TL;DR: Strong nondegenerate optical continuous-wave parametric oscillations in crystalline whispering gallery mode resonators fabricated from LiNbO3 are demonstrated.
Abstract: We demonstrate strongly nondegenerate optical continuous-wave parametric oscillations in crystalline whispering gallery mode resonators fabricated from LiNbO3. The required phase matching is achieved by geometrical confinement of the modes in the resonator.
64 citations
TL;DR: In this article, the authors introduced the definition of group velocity for a system with a discrete spectrum and applied it to a linear resonator and showed that a positive, negative, or zero group velocity can be obtained for light propagating in the whispering gallery modes of a microspherical resonator.
Abstract: We introduce the definition of group velocity for a system with a discrete spectrum and apply it to a linear resonator. We show that a positive, negative, or zero group velocity can be obtained for light propagating in the whispering-gallery modes of a microspherical resonator. The associated group delay is practically independent of the ring-down time of the resonator. We demonstrate ``stopped light'' in an experiment with a fused silica microsphere.
43 citations
Patent•
16 Feb 2007
TL;DR: An optical device, optical system, and method of generating optical beams having high angular momenta are provided in this article, which includes a whispering gallery mode resonator defining a resonator radius and an elongated waveguide having a length defined between a first end and a second end of the waveguide.
Abstract: An optical device, optical system, and method of generating optical beams having high angular momenta are provided. The optical device includes a whispering gallery mode resonator defining a resonator radius and an elongated waveguide having a length defined between a first end and a second end of the waveguide. The waveguide defines a waveguide radius which increases at least along a portion of the length of the waveguide in a direction from the first end to the second end. The waveguide radius at the first end of the waveguide is smaller than the resonator radius and the resonator is integrally formed with the first end of the waveguide.
33 citations
TL;DR: In this paper, a study of optical properties of whispering gallery mode resonators made out of as-grown nominally pure lithium niobate crystals has been conducted and the authors have observed a surprising dynamic modification of the spectrum of the resonators illuminated with the near infrared light.
15 citations
TL;DR: In this paper, the authors studied electromagnetically induced transparency in a vacuum rubidium atomic cell and showed that reflected drive radiation results in the reshaping and shift of dark resonance, and that those effects are connected with Bragg reflection of the probe radiation in optically thick atomic coherent medium modulated by the standing-wave drive field.
Abstract: We study electromagnetically induced transparency in a vacuum rubidium atomic cell and show that reflected drive radiation results in the reshaping and shift of dark resonance. We show that those effects are connected with (i) Bragg reflection of the probe radiation in optically thick atomic coherent medium modulated by the standing-wave drive field, as well as with (ii) quantum interference enhanced absorption of the probe radiation in four-level N-configuration formed due to the reflected drive field.
11 citations
Patent•
20 Sep 2007
TL;DR: In this paper, a differential temperature sensor system and a method of determining a temperature shift of an optical resonator and its surroundings are provided, which includes a light generating device capable of generating a beam having a carrier frequency, a modulator capable of modulating the beam with a sideband frequency, and an optical resonance capable of supporting an ordinary mode and an extraordinary mode.
Abstract: A differential temperature sensor system and method of determining a temperature shift of an optical resonator and its surroundings are provided. The differential temperature sensor system includes a light generating device capable of generating a beam having a carrier frequency, a modulator capable of modulating the beam with a sideband frequency, and an optical resonator capable of supporting an ordinary mode and an extraordinary mode. The system includes an ordinary mode-lock setup capable of locking the carrier frequency of the beam to the ordinary mode of the optical resonator and an extraordinary mode-lock setup capable of locking the sideband frequency of the beam to the extraordinary mode of the optical resonator by providing a specific radio frequency to the modulator substantially corresponding to a frequency shift between the ordinary mode and the extraordinary mode of the optical resonator resulting from a temperature change of the optical resonator. A processor precisely calculates the differential temperature based upon the frequency shift between the ordinary mode and extraordinary mode of the optical resonator.
6 citations
Patent•
14 Sep 2007
TL;DR: In this article, a method of shifting and fixing an optical frequency of an optical resonator to a desired optical frequency, and an optical resonance made by such a method are provided.
Abstract: A method of shifting and fixing an optical frequency of an optical resonator to a desired optical frequency, and an optical resonator made by such a method are provided. The method includes providing an optical resonator having a surface and a refractive index, and obtaining a coating composition having a predetermined concentration of a substance and having a refractive index that is substantially similar to the refractive index of the optical resonator. The coating composition inherently possesses a thickness when it is applied as a coating. The method further includes determining a coating ratio for the surface of the optical resonator and applying the coating composition onto a portion of the surface of the optical resonator based upon the determined coating ratio.
4 citations
01 Jul 2007
TL;DR: In this article, the authors report on the experimental observations of power-dependent, nonexponential decay of light stored in WGMs caused by stimulated Raman scattering in the resonator host material and show that a proper thermal annealing leads to a significant increase of the quality factors of the resonators.
Abstract: We review recent progress in fabrication, characterization, and applications of ultra-high-Q crystalline whispering gallery mode (WGM) resonators We report on the experimental observations of power-dependent, non-exponential decay of light stored in WGMs caused by stimulated Raman scattering in the resonator host material We show that a proper thermal annealing leads to a significant increase of the quality factors of the resonators Finally, we demonstrate optical continuous wave parametric oscillations in lithium niobate WGM resonators
3 citations
TL;DR: In this paper, the influence of incoherent optical pumping and beam profiling on slow light propagation in three-level atomic vapor was studied and it was shown that the optical pumping enhances the resulting group delay for a certain range of parameters.
Abstract: We report on a theoretical study of the influence of incoherent optical pumping and beam profiling on slow light propagation in three-level atomic vapor. The pumping reduces the residual unwanted absorption of the signal while destroying the atomic coherence and increasing the group velocity of light. We show that the pumping enhances the resulting group delay for a certain range of parameters. We also examine changing the cross section of the beam of light along the propagation direction by, e.g., focusing the beam, for the purpose of maintaining the drive intensity to effectively counter its absorption.
2 citations
01 Mar 2007
TL;DR: In this article, a simplified method of generating a beam of light having a relatively high value of angular momentum (see figure) involves the use of a compact apparatus consisting mainly of a laser, a whispering gallery-mode (WGM) resonator, and optical fibers.
Abstract: A simplified method of generating a beam of light having a relatively high value of angular momentum (see figure) involves the use of a compact apparatus consisting mainly of a laser, a whispering- gallery-mode (WGM) resonator, and optical fibers. The method also can be used to generate a Bessel beam. ( Bessel beam denotes a member of a class of non-diffracting beams, so named because their amplitudes are proportional to Bessel functions of the radii from their central axes. High-order Bessel beams can have high values of angular momentum.) High-angular-momentum light beams are used in some applications in biology and nanotechnology, wherein they are known for their ability to apply torque to make microscopic objects rotate. High-angular-momentum light beams could also be used to increase bandwidths of fiber-optic communication systems. The present simplified method of generating a high-angular-momentum light beam was conceived as an alternative to prior such methods, which are complicated and require optical setups that include, variously, holograms, modulating Fabry-Perot cavities, or special microstructures. The present simplified method exploits a combination of the complex structure of the electromagnetic field inside a WGM resonator, total internal reflection in the WGM resonator, and the electromagnetic modes supported by an optical fiber. The optical fiber used to extract light from the WGM resonator is made of fused quartz. The output end of this fiber is polished flat and perpendicular to the fiber axis. The input end of this fiber is cut on a slant and placed very close to the WGM resonator at an appropriate position and orientation. To excite the resonant whispering- gallery modes, light is introduced into the WGM resonator via another optical fiber that is part of a pigtailed fiber-optic coupler. Light extracted from the WGM resonator is transformed into a high-angular- momentum beam inside the extraction optical fiber and this beam is emitted from the polished flat output end. By adjusting the geometry of this apparatus, it is possible to generate a variety of optical beams characterized by a wide range of parameters. These beams generally have high angular momenta and can be of either Bessel or Bessel-related types.
1 citations
06 May 2007
TL;DR: In this paper, the authors report on the direct observation of stationary interference patterns of several running optical whispering gallery modes in an experiment with a fused silica microsphere immersed into a dye solution.
Abstract: We report on the direct observation of stationary interference patterns of several running optical whispering gallery modes in an experiment with a fused silica microsphere immersed into a dye solution.
01 May 2007
TL;DR: It is now possible to fashion transparent crystalline materials into axisymmetric optical components having diameters ranging from hundreds down to tens of micrometers, whereas previously, the smallest attainable diameter was 500 m as mentioned in this paper.
Abstract: It is now possible to fashion transparent crystalline materials into axisymmetric optical components having diameters ranging from hundreds down to tens of micrometers, whereas previously, the smallest attainable diameter was 500 m. A major step in the fabrication process that makes this possible can be characterized as diamond turning or computer numerically controlled machining on an ultrahigh-precision lathe.
06 May 2007
TL;DR: In this paper, the authors demonstrate optical continuous wave parametric oscillations in crystalline whispering gallery mode (WGM) resonators fabricated with LiNb03, achieving phase matching by geometrical confinement of the WGMs.
Abstract: We demonstrate optical continuous wave parametric oscillations in crystalline whispering gallery mode (WGM) resonators fabricated with LiNb03. The required phase matching is achieved by geometrical confinement of the WGMs.