Application of Kramers–Kronig receiver in SSB-OFDM-RoF link

We propose and investigate the use of a Kramers–Kronig(KK) receiver in a single sideband orthogonal frequency division multiplexing radio over fiber(SSB-OFDM-RoF) link based on an optical remote heterodyne solution. This scheme is effective in eliminating the signal-to-signal beating interference introduced by square-law detection of a photo-detector in an SSB-OFDM-RoF link. We extensively study the influences of different carrier-to-signal power ratios(CSPRs), laser linewidths, and transmission distances on our proposed scheme. It is proved that the KK-based receiver can reduce optimal CSPR by more than 5 dB and provide about 1.1 dB gain over the conventional mixer-based receiver scheme with CSPR of 11 dB after 75 km fiber transmission.     

Complex Modulation in Plasmon-Assisted Transmission Spectra of a Two-Slit Structure

We study the plasmon-assisted transmission of two kinds of slit structures in a 290-nm-thick silver film on a glass substrate. For the two-slit structure, the total transmission intensity spectra displays a complex modulation, which is attributed to different propagation constants of the surface plasmon polaritons （SPPs） on the silver-air and silver-glass interfaces. Replacing one of the two slits by a shallow corrugation results in a simple sinusoidal intensity modulation because of the only effective SPP excitation and propagation on the silver-air interface. These confirm the role of different SPP propagations and interference in the transmission properties of metal nanoslits.     

Kramers–Kronig relations in modulation polarimetry diagnostics of glass-ceramics

It has been found that, in an aluminosilicate glass-ceramic sample cut from a massive ingot, there is a correlation of the residual stress with the temperature gradient. The magnitude and coordinate dependence of the stress along the temperature gradient have been determined from the stress-induced linear birefringence measured by the modulation polarimetry technique. Its functional relationship has been established in the form of the Poisson equation with the heterogeneity of the composition due to the preparation conditions. It has been shown that, in the absence of a temperature gradient, the birefringence and dichroism related by the Kramers–Kronig relation play the role of thermodynamic variables.     

Local Kramers–Kronig Relations between the Attenuation Coefficient and Phase Velocity of Longitudinal Ultrasonic Waves in Polymer Composites

Acoustical Physics - The relationship between the experimentally obtained attenuation coefficient and dispersion of the phase velocity of longitudinal ultrasonic waves in polymer composite...     

Kramers–Kronig analysis of the optical constants of magnetite,pyrite, and chalcopyrite in the microwave range

The optical constants of a series of ore minerals (pyrite, magnetite, and chalcopyrite) have been analyzed in the microwave range using the Kramers–Kronig method. The spectral dependences of the reflectance of these minerals in a wide frequency range (from deep UV to microwave) have been plotted based on numerous experimental data from different sources. These dependences made it possible to calculate the optical constants of the minerals under study in a frequency range of 12–145 GHz and compare them with the results of the theoretical and laboratory studies published in different sources.     

Analysis of the Optical Transmission of a Bismuth Silicone Oxide Crystal with Тemporal-Wavelength Modulation of Probe Radiation

Russian Physics Journal - We present results of simulation of time dependences of the Bi12SiO20 crystal transmission coefficient with harmonic wavelength modulation of probe radiation. The...     

Spin-Wave Resonance in One-Dimensional Magnonic Crystals by an Example of Multilayer Co–P Films

Physics of the Solid State - Layered magnetic films of Co–P alloy, which are sets of laminates with certain atomic and chemical structures, have been investigated by spin-wave resonance....     

Growth of Faceted Pores in a Crystal by the Burton–Cabrera–Frank Mechanism

Physics of the Solid State - The growth of a faceted pore in a crystal by the Burton–Cabrera–Frank mechanism under action of a mechanical tensile load is considered. The growth is...     

Transmission Probability of an Ultracold Atom in the Presence of Atomic Coherence

We investigate the transmission probability of an ultracold V-type three-level atom passing through a micromaser cavity,in the presence of atomic coherence which is established by a coherent driving field.We show that the transmissibility of this micromaser system with the atomic coherence is better than that of the ordinary micromaser system without atomic coherence.When the driving field is strong enough,for any cavity length the ultracold atom can pass through the micromaser cavity freely.     

Modulation instability of an intense laser beam in an unmagnetized electron–positron–ion plasma

The modulation instability of an intense circularly polarized laser beam propagating in an unmagnetized, cold electron–positron–ion plasma is investigated. Adopting a generalized Karpman method, a three-dimensional nonlinear equation is shown to govern the laser field. Then the conditions for modulation instability and the temporal growth rate are obtained analytically. In order to compare with the usual electron–ion plasmas, the effect of positron concentration is considered. It is found that the increase in positron-to-electron density ratio shifts the instability region towards higher vertical wave numbers but does not cause displacement along the parallel wave number direction, and the growth rate increases as the positron-to-electron density ratio increases.     

Absorption Spectra of Gasolines in the Region 1090–1220 nm

The difference absorption spectra of different grades of gasoline (A-76, AI-92, and AI-95) with octane numbers lying within 76–85 have been investigated experimentally in comparison with hydrocarbons: isooctane, benzene, and n-heptane. The spectra obtained contain absorption bands of the CH₃, CH₂, and CH groups and supposedly of the olefin double bond. The possibility of determining the octane number of an unknown grade of gasoline by using the absorption of a measured difference spectrum at one selected wavelength is shown.     

Infrared Spectra of the Halothane–Trimethylamine Complex in Liquefied Krypton

Optics and Spectroscopy - The IR absorption spectra of solutions of mixtures of halothane (C2HBrClF3) and trimethylamine ((CD3)3N) in liquefied krypton were obtained and analyzed. Bands assigned to...     

Optical Constants of an Apatite Single Crystal in the IR Range of 6–28 μm

On the basis of polarized IR-reflection spectra in the range of 5000–350 cm^–1 measured from the natural face of an optically transparent fluorapatite single crystal, components of a complex refractive index (optical constants) for radiation-vector orientations E ‖ c and E ⊥ c have been calculated by the Kramers–Kronig method. The fluorapatite single crystal has been chosen from several samples: it contains a minimum amount of impurities and has a high degree of crystallinity in accordance with the criteria of IR spectroscopy and Raman spectroscopy. Tabular data on optical constants for ordinary and extraordinary rays are given for the IR range of 6–28 μm. The obtained absorption spectra are compared with the results of quantum-chemical ab initio calculations within the B3LYP simulation.     

Transmission and Conversion of Electromagnetic Radiation by Photonic Crystal Metal–Dielectric Systems Based on Opals

Optics and Spectroscopy - An experimental study of the optical properties of two types of metal–dielectric composites based on opal matrices has been carried out: (1) layered structures,...     

Modulation of electrons and positrons in 2006–2015 in the PAMELA experiment

The PAMELA magnetic spectrometer was launched aboard the Resurs DK-1 satellite into a nearpolar circumterrestrial orbit with an altitude of 350–600 km to study fluxes of the particles and antiparticles of cosmic rays in the wide energy range of ~80 MeV to several hundred gigaelectronvolts. The results from observations of temporal variations in electron and positron fluxes in 2006–2015 are presented. The ratio of electron and positron fluxes measured in this time interval reveals a dependence on the rigidity of particles, the solar activity, and the polarity of the solar magnetic field.