Nickolai Kukhtarev

Photoinduced Electric Current in Fe-Doped KNbO3

Photorefractive KNbO3:Fe is characterized by monitoring of the electric currents induced in the crystal that are due to applied illumination. Important photorefractive parameter values, such as the Maxwell relaxation time, carrier-diffusion length, carrier-screening length, and the magnitude of the photogalvanic current are thereby estimated.

New optical approach to decontamination technologies based on photoinduced running gratings

A basic phenomenological model for photoinduced conductiv- ity suitable for a wide variety of photosensitive and photoconductive ma- terials is developed. The modulation of photoconductivity and creation of an internal electric field by spatially modulated light patterns in different materials are described. The moving gratings of photoconductivity and electric fields can be used for optical tweezing of harmful impurities in the liquid solutions.

Photogalvanic effect for water splitting by pulsed electrolysis enhanced by magnetic fields

We suggest to use photoinduced photogalvanic electrical discharges produced by the ferroelectric Fe: LiNbO3 crystals for effective water splitting for production of oxygen and hydrogen by pulsed electrolysis. Electrical self-pulsations may be initiated by CW illumination with incoherent light, including Sun-light. Electrical pulses ( in microsecond range and with kV amplitude) are generated by the bulk photovoltaic (also called photogalvanic) effect. For separation of oxygen and hydrogen gases we apply magnetic field in Hall-effect configuration, with crossed electric and magnetic fields . Adding H-field to the traditional electrolysis scheme in the Hall effect geometry may give new opportunity for control of oxygen and hydrogen production. In this geometry water will be rotated that helps separation of oxygen and hydrogen. Rotation of water explained by the action of Lorentz force in geometry with cylindrical electrodes (cylindrical electrolyzer) that move oxygen and hydrogen bubbles with different signs of charges in the same directions. Hydrodynamic modeling suggest that converse effect: generation of electrical current, when water is rotating in the magnetic field, is possible to realize.

Assessment of 3-D Angular Movements of Diffuse Objects Using Holographic Interferometry

We have developed a dynamic holographic interferometry (DHI) setup to measure changes in attitudes, distortions and vibrations of objects, using a holocamera. Digital algorithms have been developed to calculate above parameters from DHI images.

Standard Photorefractive Model as a Foundation of Real-Time Holography

Publisher Summary This chapter presents the general form of starting equations describing known and expected results stemming from the standard photorefractive model (SPM). Taking into account the growing interest in the spatiotemporal patterns in different fields of modern science, the chapter presents equations in the appropriate three-dimensional (3D) form. The evolution of the SPM starting from the original semiconductor version is described. Being based on the description of photoionization and drift–diffusion recombination, the SPM is valid for semiconductors as well as for a variety of other photosensitive materials: ferroelectrics, photorefractive polymers, and liquid crystals. In general, the SPM is valid for those materials where drift–diffusion approximation can be induced together with photogeneration recombination. This model successfully explains the self-diffraction, holographic recording, and storage as well as predicted holographic electromotive force (EMF) and anisotropic photoconductivity.