In the last 30 days

• Open/close Elementary processes of stimulated emission

  Pavel V Elyutin 2012 Quantum Electron. 42 192 Tag this article

  Article References Full text PDF (773 KB)

  We consider the simplest process of stimulated emission, i.e., evolution of an excited two-level atom interacting with a quantized electromagnetic field being initially in a one-photon state under different boundary conditions imposed on the field. We study the kinetics of evolution, spectral properties and modal composition of the radiation field emerging in such processes. It is shown that in the general case this field is only partly composed of doubly occupied modes.

• Open/close Photonic crystal fibres in biomedical investigations

  Yu S Skibina et al 2011 Quantum Electron. 41 284 Tag this article

  Article References Full text PDF (4.01 MB)

  The state of the art in the field of design and study of photonic crystal fibres for biomedical applications is considered and some original results recently obtained by the authors are presented. Optical properties of the fibres that offer prospects of their wide application as biological sensors, 'labs-on-a-chip', and facilities of electromagnetic radiation control in a wide range of wavelengths aimed at designing novel biomedical instrumentation are considered

• Open/close Au-coated ZnO nanostructures for surface enhanced Raman spectroscopy applications

  A O Dikovska et al 2012 Quantum Electron. 42 258 Tag this article

  Article References Full text PDF (7.01 MB)

  Thin ZnO nanostructured films were produced by pulsed laser deposition (PLD) for surface enhanced Raman spectroscopy (SERS) studies. The experimental conditions used for preparation of the samples were chosen to obtain different types of ZnO nanostructures. The Raman spectra of rhodamine 6G (R6G) were measured at an excitation wavelength of 785 nm after coating the ZnO nanostructures with a thin Au layer. The influence of the surface morphology on the Raman signal obtained from the samples was investigated. High SERS signal enhancement was observed from all Au-coated ZnO nanostructures.

• Open/close IR luminescence of tellurium-doped silica-based optical fibre

  Evgenii M Dianov et al 2012 Quantum Electron. 42 189 Tag this article

  Article References Full text PDF (396 KB)

  Tellurium-doped germanosilicate fibre has been fabricated by the MCVD process. In contrast to Te-containing glasses studied earlier, it has a broad luminescence band (full width at half maximum of ~350 nm) centred at 1500 nm, with a lifetime of ~2 μs. The luminescence of the fibre has been studied before and after gamma irradiation in a ⁶⁰Co source to 309 and 992 kGy. The irradiation produced a luminescence band around 1100 nm, with a full width at half maximum of ~400 nm and lifetime of ~5 μs.

• Open/close Coherent beam combining of 2-μm fibre lasers

  Pu Zhou et al 2012 Quantum Electron. 42 220 Tag this article

  Article References Full text PDF (492 KB)

  Coherent beam combining of 2-μm fibre lasers is studied numerically. Such lasers are a suitable candidate for creation of a beam combining module due to their higher nonlinear effect and optical damage threshold compared to their 1-μm counterparts. The calculations results show that radiation of a 1-μm fibre laser has a better focusing property in free-space due to a smaller wavelength, whereas a 2-μm laser beam has a better focusing capability in the target-plane under conditions of real atmospheric turbulence.

• Open/close Interaction of noncollinear femtosecond laser filaments in sapphire

  A A Dergachev et al 2012 Quantum Electron. 42 125 Tag this article

  Article References Full text PDF (1.24 MB)

  The interaction of two coherent femtosecond laser pulses, propagating at a small angle with respect to each other in a sapphire crystal in the filamentation regime, has been investigated numerically and experimentally. Distributions of the fluence and free-electron density in the laser-plasma channels formed in the crystal are obtained. Additional filaments are found to form outside the plane of initial pulse propagation.

• Open/close High-peak power, passively Q-switched, composite, all-polycrystalline ceramic Nd : YAG/Cr⁴⁺:YAG lasers

  O Sandu et al 2012 Quantum Electron. 42 211 Tag this article

  Article References Full text PDF (568 KB)

  High-peak power, passively Q-switched, composite Nd : YAG/Cr ⁴⁺ : YAG lasers consisting of all-polycrystalline bonded Nd : YAG and Cr ⁴⁺:YAG ceramics are developed, and two applications of such lasers are discussed. A 1.1-at. %-doped Nd : YAG/Cr ⁴⁺:YAG ceramic laser is fabricated, which is quasi-cw pumped by a diode laser in the Hz-range, delivering laser pulses of 2.5-mJ energy and 1.9-MW peak power. By frequency doubling the laser output in a LiB ₃O ₅ (LBO) nonlinear crystal at room temperature, 0.36-mJ, 0.3-MW green laser pulses with 27 % conversion efficiency are produced at 532 nm. Furthermore, a highly doped (1.5-at. %) Nd : YAG/Cr ⁴⁺:YAG ceramic laser operates successfully in the range of pulse repetition rates from 50 to 500 Hz, yielding 0.8-to-1.0 mJ pulses with a peak power around 1 MW. The laser output beam is amplified in a master-oscillator — power-amplifier (MOPA) system to generate laser pulses with 11-mJ energy at a 250-Hz repetition rate.

• Open/close Femtosecond lasers for microsurgery of cornea

  Sergei K Vartapetov et al 2012 Quantum Electron. 42 262 Tag this article

  Article References Full text PDF (4.16 MB)

  The review of femtosecond laser installations for medical applications is given and a new femtosecond ophthalmologic system for creation of a flap of corneal tissue during the LASIK operation is described. An all-fibre femtosecond laser emitting ~400-fs pulses at 1067 nm is used. The pulse repetition rate can vary from 200 kHz up to 1 MHz. The output energy of the femtosecond system does not exceed 1 μJ. A specially developed objective with small spherical and chromatic aberrations is applied to focus laser radiation to an area of an eye cornea. The size of the focusing spot does not exceed 3 μm. To process the required area, scanning by a laser beam is applied with a speed no less than 5 m s ^-1. At a stage of preliminary tests of the system, the Κ8 glass, organic PMMA glass and specially prepared agarose gels are used as a phantom of an eye. The femtosecond system is successfully clinically tested on a plenty of eyes of a pig and on several human eyes. The duration of the procedure of creation of a corneal flap does not exceed 20 s.

• Open/close Whispering-gallery waves

  Anatolii N Oraevsky 2002 Quantum Electron. 32 377 Tag this article

  Article References Full text PDF (2.18 MB)

  A review of the theory of the natural waves (eigen-modes) in a dielectric sphere is presented. A special attention is paid to the eigenmodes with large radial and azimuthal indices, the so-called whispering-gallery modes. The experimental results of the spectroscopic study of modes in a dielectric sphere are reported. The fields of applications of whispering-gallery modes are discussed.

• Open/close Oleg Nikolaevich Krokhin

  Ivan B Kovsh and Aleksandr S Semenov 2012 Quantum Electron. 42 280 Tag this article

  Article References Full text PDF (1008 KB)

  Academician Oleg Nikolaevich Krokhin, prominent physicist and organiser of science, laureate of Lenin and State Prizes, Editor-in-Chief of Quantum Electronics was 80 on 14 March 2012.