The Surface Photogalvanic and Photon Drag Effects in Ag/Pd Metal-Semiconductor Nanocomposite.

We performed the investigation of the polarization-sensitive photocurrent generated in silver-palladium metal-semiconductor nanocomposite films under irradiation with nanosecond laser pulses at the wavelength of 2600 nm. It is shown that in both the transverse and the longitudinal configuration, the surface photogalvanic (SPGE) and photon drag effects (PDE) contribute to the observed photocurrent. However, the temporal profile of the transverse photocurrent pulse is monopolar at any polarization and angle of incidence, while the temporal profile of the longitudinal photocurrent pulse depends on the polarization of the excitation beam.

Interaction of polarization-sensitive surface photocurrents in semitransparent CuSe/Se film.

We demonstrate that the transverse polarization-sensitive photoresponse of the CuSe/Se nanocomposite film deposited on a transparent substrate depends on whether the film is irradiated from the air side or substrate side. In particular, the nanosecond photocurrent pulse is either bipolar or unipolar pulse depending on which interface beam hits first. The observed phenomenon can be described in terms of the interplay between counter-propagating photocurrents generated at the air/nanocomposite and substrate/nanocomposite interfaces due to the surface photogalvanic effect.

Enhanced saturable absorption in the laser-treated free-standing carbon nanotube films.

We demonstrate an increase of optical transmittance and saturable absorption of laser-treated free-standing single-walled carbon nanotube (SWNT) films. The combined acid and low-power non-destructive laser treatment ensures an enhancement of linear transmittance across the visible range and double-digit increase of the saturable absorption of femtosecond laser radiation at 795 nm. The saturable absorption coefficient and the ratio of saturable to non-saturable losses increase by 26% and 35%, correspondingly, while the saturation intensity decreases by 20% because of the treatment.

Circular photocurrent in the carbon nanowall film.

We report the helicity-dependent photocurrent in the carbon nanowall film synthesized on the silicon substrates by the chemical vapor deposition technique. The film is composed of multilayer graphene flakes grown along the substrate normal. We measured the transverse photocurrent generated in the film under irradiation with nanosecond laser pulses by depositing two conductive electrodes along the plane of incidence.

Interplay of the photon drag and the surface photogalvanic effects in the metal-semiconductor nanocomposite.

Photon drag effect (PDE) and surface photogalvanic effect (SPGE) can be observed in centrosymmetric media and manifest themselves in photocurrents, the magnitude and polarity of which depend on wavevector and polarization of the excitation laser beam. PDE photocurrent originates from the transfer of the photon momentum to a free charge carrier, while SPGE photocurrent is due to diffuse scattering of the photoexcited carriers in the subsurface layer. However, despite the different underlying physical mechanisms, these photocurrents have almost indistinguishable dependencies on the polarization and the angle of incidence of the excitation laser beam.

Femtosecond Circular Photon Drag Effect in the Ag/Pd Nanocomposite.

We report on the observation of the helicity-dependent photoresponse of the 20-μm-thick silver-palladium (Ag/Pd) nanocomposite films. In the experiment, 120 fs pulses of Ti:S laser induced in the film an electric current perpendicular to the incidence plane. The photoinduced current is a linear function of the incident beam power, and its sign depends on the beam polarization and angle of incidence.

Near-IR nonlinear optical filter for optical communication window.

We report on a high performance nonlinear optical filter for the telecommunication window that employs detonation nanodiamonds (NDs). The nanosecond Z-scan experiments revealed that the heavy water ND suspensions enable strong optical limiting in the wavelength range of 1400-1675 nm. We observed an enhancement of the optical limiting performance in the blue part of the communication window.

Size effect on the optical limiting in suspensions of detonation nanodiamond clusters.

We report on the optical limiting (OL) in stable aqueous suspensions of detonation nanodiamond (ND) clusters with average size of 50, 110, and 320 nm. The nanosecond Z-scan measurements at wavelength of 532 nm revealed that the larger the cluster size, the better the OL performance and the higher the ray stability of the ND suspension. Our analysis showed that the nonlinear scattering and the nonlinear absorption are the dominant mechanisms of OL in aqueous ND suspensions.

Photon-drag effect in single-walled carbon nanotube films.

We observed an interaction of single-walled carbon nanotube films with obliquely incident nanosecond laser radiation in visible and infrared regions generating unipolar voltage pulses replicating the shape of the laser pulses. The photoelectric signal significantly depends on the laser polarization and has maximum value at the laser beam incidence angle of ±65° and at the film thickness of 350 nm. The results are explained in the framework of the photon-drag effect.

[Use of autologous progenitor cells of the bone marrow in treatment of patients with lower-limb atherosclerosis obliterans].

Presented herein are the outcomes of using autologous progenitor cells of the bone marrow in a total offorty-two male patients suffering from atherosclerosis obliterans of the lower-limb arteries with degree II B of ischaemia according to the classification of A. V. Pokrovsky, preconditioned by involvement of the femoropopliteal-tibial segment with no possibility to perform a reconstructive operation.

[Diagnosis and treatment of generalized forms of sarcoidosis].

A total of 132 patients with generalized sarcoidosis (GS) who amounted to 2.8% out of 4700 examinees and followed-up patients with respiratory sarcoidosis were studied. The pathomorphological study of biopsy specimens, X-ray functional, and immunological studies are of great importance in the diagnosis of GS.

[The use of the enterosorbent polifepan in the combined treatment of patients with dermatoses].

Polyfepan, an enterosorbent, was used in the treatment of 96 dermatologic patients. The treatment proved to be effective in those with toxicoderma, secondary xanthomatosis, porphyria cutanea tarda, skin itching, and urticaria, particularly in the cases when toxic exposures and gastrointestinal conditions contributed to the disease pathogenesis. Polyfepan enterosorption is harmless, well-tolerated, and simple.