The well-being of a person and the efficiency of his production activities are largely determined by the correspondence of the biorhythms of a person to his working schedule. As it was established at the molecular and genetic level, the main physical factor that allows us to control human biorhythms is light (Nobel Prize 2017). Modern studies of ophthalmologists have found a third type of photoreceptors in human eyes, in addition to rods and cones. These receptors are not intended for receiving images, but primarily for correcting biorhythms, including controlling the process of awakening. The third type of receptors are sensitive mainly in the short-wave, blue region of the visible spectrum. In recent years light-emitting diodes have appeared. However, these devices do not take into account the current requirements for the spectrum of the awakening radiation, and even more so do not allow it to be adjusted during the awakening process according to the necessary program. We offer a technology for gentle awakening of the employee, based on modern concepts of ophthalmology and biorhythmology. The technology uses computer control of the physical factors of awakening-light and sound.

Polymer nanocomposite films can be made impenetrable to air, light, aromatic substances, steam. This stipulates their wide use for packaging, primarily food products. Such films thickness control is an important technological moment of their manufacturing, and it must be non-contact and non-destructive. Most of films made of nanocomposite polymers are transparent to visible and infrared light. In this article a new method of the data processing aimed to determine the film thickness from the angle dependence of the laser beam reflection coefficient by the film is offered. The offered procedure and the experimental technique realizing it permit to decrease the thickness determination uncertainty to 150 nm while measuring the film thickness in the range from 0,01 mm to 1,0 mm.

Non-contact non-destructive laser-interferometric methods for measuring several electrophysical parameters of semiconductor and dielectric layers are proposed. They are the lifetime of charge carriers for electrons and holes separately; parameters of recombination centers, namely their concentration and capture cross-sections; bulk volume lifetime and rate of surface recombination, as well as the diffusion length of charge carriers. The methods are based on the interference-absorption interaction in a semiconductor of two laser radiations with different wavelengths. Short-wave injection radiation generates additional charge carriers in the material, which leads to a change in its optical constants at the wavelength of the other – long-wavelength probing laser radiation – and to modulation of this radiation as it passes through the sample of the studied material. The means for implementing the proposed methods and methods for processing the modulation signal for determining the parameters of the investigated samples are developed. The methods have been successfully tested on samples of such materials as germanium, silicon, indium antimonide and cadmium-mercury-tellurium alloy. It is shown that the methods can be used both in scientific research and electronic industry.

Non-contact non-destructive laser-interferometric methods for measuring several electrophysical parameters of semiconductor and dielectric layers are proposed. They are the lifetime of charge carriers for electrons and holes separately; parameters of recombination centers, namely their concentration and capture cross-sections; bulk volume lifetime and rate of surface recombination, as well as the diffusion length of charge carriers. The methods are based on the interference-absorption interaction in a semiconductor of two laser radiations with different wavelengths. Short-wave injection radiation generates additional charge carriers in the material, which leads to a change in its optical constants at the wavelength of the other – long-wavelength probing laser radiation – and to modulation of this radiation as it passes through the sample of the studied material. The means for implementing the proposed methods and methods for processing the modulation signal for determining the parameters of the investigated samples are developed.The methods have been successfully tested on samples of such materials as germanium, silicon, indium antimonide and cadmium-mercury-tellurium alloy. It is shown that the methods can be used both in scientific research and electronic industry.

We propose the contactless nondestructive method for determination of the carrier diffusion length in semiconductors and dielectrics. The method is based on optical generation of non-equilibrium carriers at one point of the studied sample and the laser interference measurement of their concentration at another point. When changing the distance between these points, a decrease in the carrier concentration is observed. It depends on the carrier diffusion length, which is determined by comparing the experimental and theoretical dependences of the probe signal on the divergence of the injector and probe beams. We have studied silicon samples protected by an insulator layer and without any covering. The method can be used in scientific research and the electronics industry.

Nondestructive optical methods for measuring of the "thick" films thickness of the order of 0,001-1,00 mm are analyzed. It is shown that using the laser beam radiation and modern optical and electronic schemes possible to decrease the time of single measurement to Ims and less at the measuring frequency of 10-50 Hz. The possibility of measuring thickness and spreading coefficient and evaporation kinetics of liquid films is demonstrated. A new computer method of the data processing aimed to determine the film thickness from the angle dependence of the laser beam reflection coefficient by the film is offered. The offered procedure and the experimental technique realizing it permits to decrease the thickness determination uncertainty to the order of ten.

A new laser interferometric method for measuring the carrier diffusion length in semiconductors is proposed. The method is based on the interference–absorption interaction of two laser radiations in a semiconductor. Injected radiation generates additional carriers in a semiconductor, which causes a change in the material’s optical constants and modulation of the probing radiation passed through the sample. When changing the distance between carrier generation and probing points, a decrease in the carrier concentration, which depends on the diffusion length, is recorded. The diffusion length is determined by comparing the experimental and theoretical dependences of the probe signal on the divergence of the injector and probe beams. The method is successfully tested on semiconductor samples with different thicknesses and surface states and can be used in scientific research and the electronics industry.

The Casimir pressure on the dielectric layer in metal-dielectric-semiconductor (MDS) structures is calculated in the framework of the Lifshitz theory at nonzero temperature. In this calculation the standard parameters of semiconductor devices with a thin dielectric layer are used. We consider the thickness of a layer decreasing from 40 to 1 nm. At the shortest thickness the Casimir pressure achieves 8 MPa. At small thicknesses the results are compared with the predictions of nonrelativistic theory.

We calculate the interaction energy and force between atoms and molecules and single-walled carbon nanotubes described by the Dirac model of graphene. For this purpose the Lifshitz-type formulas adapted for the case of cylindrical geometry with the help of the proximity force approximation are used. The results obtained are compared with those derived from the hydrodymanic model of graphene. Numerical computations are performed for hydrogen atoms and molecules. It is shown that the Dirac model leads to larger values of the van der Waals force than the hydrodynamic model. For a hydrogen molecule the interaction energy and force computed using both models are larger than for a hydrogen atom.

Two optical-mechanical installations realizing the fast variation of angle of laser beam incidence upon a steady sample surface with subsequent registration of reflected beam intensity are described. Application of spherical lenses or mirrors instead of the elliptic ones lowers the device cost significantly.

The Casimir force pressure on the insulating layer in metal-insulator-semiconductor structures with parameters close to those used in the production of semiconductor devices has been calculated. It has been shown that the Casimir force pressure increases tenfold and reaches several tens of pascals as the insulator thickness decreases from 80 to 40 nm. The metal layer thickness and the presence of the surface layer with a high charge carrier concentration in the semiconductor have a slight effect on calculated values of the Casimir pressure.

The van der Waals and Casimir-Polder interaction of different atoms with graphene is investigated using the Dirac model which assumes that the energy of quasiparticles is linear with respect to the momentum. The obtained results for the van der Waals coefficients of hydrogen atoms and molecules and atoms of metastable He* and Na as a function of separation are compared with respective results found using the hydrodynamic model of graphene. It is shown that, regardless of the value of the gap parameter, the Dirac model leads to much smaller values of the van der Waals coefficients than the hydrodynamic model. The experiment on quantum reflection of metastable He* and Na atoms on graphene is proposed which is capable to discriminate between the two models of the electronic structure of graphene. In this respect, the parameters of the phenomenological potential for both these atoms interacting with graphene described by different models are determined.

We present the results of investigations of the technique based on the principles of laser interferometry for measuring the thickness of two-layers films.The actuality of this kind of measurements is a result of necessity to control the geometric parameters of such films in scientific research and industry. The method of measurement is based on the analyses of the dependence of reflection coefficient as a function of the incidence angle of the laser beam due to the interference. To measure such dependencies we had designed experimental setups, described in our articles. This apparatus gives an ability to make the measurements of dependence of reflection coefficient as a function of the incidence angle in the range of angles from 30 degrees to 60 degrees. The temporal duration of a single measurement is less than 0.2 ms, the diameter of probing spot is 30 mu m and illuminance is less than 1 mW/mm(2). Fast measurement of angle dependence allows to get many data points that give an ability to determinate the parameters of two-layers films with high fidelity and precision.The possibility to determinate film's parameters follows from the analysis of the character of theoretical dependencies of the reflection coefficient R as a function of thicknesses of two layers with the different incidence angle of the laser beam theta. It can be seen that the reflection coefficients considerable depend on the layers thicknesses and the incidence angle. It gives an ability to design a technique to ascertain the simple correspondence among the dependence R=f(theta) and the parameters of the film layers.An efficiency of this method was experimentally tested. We performed a series of measurements using the semiconductor structures Si3N4/SiO2/Si having different thicknesses of the films Si3N4 and SiO2, produced by the concern "Integral" (Minsk). The analysis of experimental and theoretical results shows that the described techniques can be applied for measuring the parameters of the multi-layers structures.

The result of bulk lifetime measurements in high purity silicon are presented. For this investigation we offer a new method and technique for determination of the bulk value of the excess carrier lifetime in high purity silicon. The effective value of the lifetime being measured in such a material depends on the dimensions of the ingot. In our method the sample to be investigated is illuminated by the modulated radiation of the AlGaAs light-emitting diode (LED), which generates the excess carriers, and by the probe beam of the He-Ne laser (λp = 3.39 μm), which becomes modulated when passing through the sample. The bulk lifetime is determined by the analysis of the dependence of the phase shift between these two modulations versus the distance r between the points on the sample surface illuminated by the sources.

The design and operation of a programmable system for on-line measurements of the thickness kinetics of single-layer liquid films are described. The system is characterized by a response time less than or equal to 200 mu s, a measurement rate up to 100 s(-1), and a range of measured thicknesses extending from 5 mu m to 0.3 mm. The evaporation and spread rates are given for three different liquids.

We devised and tested a rapidly acting interferometer for measuring the thickness of transparent films, Its operating principle is based on the dependence of the reflection factor of a laser beam by a film on the angle of incidence. The angle of incidence is changed with the aid of a nonspherical optical system. One measurement takes less than 0.001 sec so that nonuniformities of the thickness of films can be measured and the kinetics of the change of thickness of films can be investigated. The diameter of a sounding point is less than 100 mu m.

We describe a method, and the results thereof, for contactless local determination of the excitation energy of recombination centres, their concentration, and the electron and hole capture coefficients in Cd0.3Hg0.7Te. The method suggested is based on analysis of the experimental temperature dependence of electron and hole lifetimes obtained by infrared laser interferometry.

In this paper we offer a new method and technique for the separate measuring of both excess electron and excess hole lifetimes at temperatures from 77 K to 300 K. The contactless non-destructive method is based on simultaneous irradiation of the sample by CO2-laser probe beam (λz = 10.6 Μm) and by the beam of a wavelength-tunable (5.3–6.3 Μm) CO-laser which is generating electron-hole pairs. The influence of the processing technology on charge carrier lifetimes in InSb is studied by this method.

A stabilized continuous CO laser is described that is simple to construct and is tunable over 540 lines of the band of 5.3-63-mu-m. The output power at the strongest lines is almost-equal-to 600 mW. The relative power instability is less-than-or-equal-to 2% over 1 h of operation.