Effect of broadband incoherent light on the photoresponse of lithium niobate crystals

The effect of broadband incoherent light on the local photoresponse of lithium niobate crystals has been experimentally investigated. It is shown that a previously induced electric field affects the dependence of the photovoltage on time and impurity type and concentration. The pyroelectric effect significantly influences the photoprocesses in lithium niobate crystals, especially in the initial stage of illumination.     

Experimental modeling of the temperature dependence of the transfer function of rotational motion sensors based on electrochemical transducers

The most important advantage of electrochemical transducers of motion parameters (ECT) is the high steepness of conversion of the mechanical signal to electric current. However, the working characteristics of ECT strongly depend on the temperature so that the use of ECT in precision measuring instruments requires the accurate compensation of temperature variations of its characteristics. A method of temperature measurements is developed aimed at modeling the temperature behavior of the ECT transfer function. A model of temperature behavior of ECT-based rotational motion transducers is elaborated. Results of tests which demonstrate good applicability of this model are shown.     

Technological principles of motion parameter transducers based on mass and charge transport in electrochemical microsystems

The most important advantage of motion parameter transducers based on mass and charge transport in electrochemical systems is exceptionally high rate of mechanical signal conversion to electric current. Devices of this class are based on the principle of diffusion charge transport under the conditions of forced convection appearing as a result of external acceleration. This work shows the possibility of development of modern high-technology devices based on an electrochemical transducer developed using up-to-date microelectronic technologies.     

Effects of electron–electron scattering in wide ballistic microcontacts

We consider effects of electron–electron scattering in wide ballistic microcontacts. Using a semiclassical Boltzmann equation, we obtain a positive correction to the Sharvin conductance that results from electron–electron collisions in the leads. The correction is linearly dependent on temperature at high temperatures T?eV$T?\mathit{eV}$ and proportional to |V|$\left|V\right|$ at high voltages eV?T$\mathit{eV}?T$. Magnetic field leads to strong suppression of this positive correction that results in a positive magnetoresistance in weak fields. As electron–electron scattering affects the conductance, it also influences the noise. At low voltages the noise is defined by the Nyquist relation and at high voltages it is related with the inelastic correction to the current by the Shottky formula δS=2eδI$\delta S=2e\delta I$.     

Magnetotunneling spectroscopy of polarons in a quantum well of a resonant-tunneling diode

Resonant tunneling of electrons is thoroughly studied in in-plane magnetic fields. Anticrossing is revealed in a spectrum of two-dimensional electrons at energies of optical phonons. The magnetic field changes the momentum of tunneling electrons and causes a voltage shift of a resonance in the tunnel spectra in accordance with the electron dispersion curve. Anticrossing is clearly observed in second derivative current-voltage characteristics of a resonant tunneling diode made of a double-barrier Al_0.4Ga_0.6As/GaAs heterostructure.     

Diffusion Sensor of Mechanical Signals: Frequency Response at High Frequencies

The frequency response of a diffusion transducer with gauze electrodes, studied theoretically at high frequencies, is proportional to ^-3/2 starting with = D/R ² at < /R ² and to ^-1 at > /R ². Here, = 2f, f is the signal frequency, the electrolyte viscosity, D a diffusion coefficient, and R the radius of the gauze filaments. The calculation is compared with experiment.     

The Linear Kerr Effect

Russian Physics Journal -     

Electrooptical modulation of broadband light with Gaussian amplitude distribution over the spectrum

Physical principles of the operation of an optical modulator that employs, as a light source, a laser or light-emitting diode with a spectral width up to several tens of nanometers are considered. The half-wave voltage and modulation depth of the light are found with allowance for the spectral distribution of the amplitude and refractive index dispersion.