A comparative analysis of photodetectors based on TiS2 nanosheets and on TiS2 nanosheets functionalized with silver nitrate is carried out. TiS2 nanosheets were synthesized by a chemical vapor transport technique, followed by a 1-hour ultrasonication treatment. The obtained solution was deposited between interdigitated electrodes fabricated on the surface of a flexible substrate using a dielectrophoresis process. Polyethylene terephthalate was used as a flexible substrate material. The characteristics of the fabricated photodetectors were determined by illuminating them with tunable-power laser light at 1064 nm. A significant effect of silver nitrate particles scattered in the volume of the photodetector sensitive material on its efficiency is observed. The superiority of the photodetector based on TiS2 nanosheets functionalized with silver nitrate is demonstrated. This photodetector demonstrates a significant response for all the laser light powers used (11.6, 19.6, 51, 100, and 150 mW), shows fast response (0.23±0.01 s) and recovery (0.49±0.02 s) times, coupled with high sensitivity (260∙103±7∙103 A/W), quantum efficiency (303∙103±8∙103 A/W∙nm) and detectivity (3.10∙1013±0.09∙1013 Jones) at an incident laser light power of 11.6 mW. The results obtained in this study can be used for the development and optimization of modern optoelectronic devices.

A problem of optimizing the subwavelength microrelief of a binary cylindrical transmissive diffractive lens (DL) with a 300-mm focal length for a wavelength of λ=141 μm was considered. High-resistivity silicon was chosen as the DL substrate material. The angle of incidence of the illuminating beam was taken to be π/6. The optimization parameters were the height of the DL profile and the fill factor of the groove. The main goal of optimizing the design was to increase the diffraction efficiency of the lens. The DL diffraction efficiency was calculated using a Fourier mod method. The DL was fabricated by plasma-chemical etching (Bosch process) of the surface of a silicon substrate. The diffraction efficiency of the calculated lens was estimated to be 70%. However, a full-scale experiment showed the real efficiency to be much lower. These differences are related to both errors in the manufacturing process of the DL and non-ideal thickness parameters of the silicon wafers.

Present work deals with the development of high-speed NO2sensor based on functionalized Single Walled Carbon Nanotubes (SWNTs). To improve the sensing properties of SWNTs, SWNTs is functionalized with the enzyme N-benzyloxycarbonylglycine (Z-Gly-OH). Various parameters of the functionalization process such as time and temperature are also optimized and analysed in detail. Z-Gly-OH has created a functionalization of the 1,3-dipolar cycloaddition type, which is capable of doing modification in the properties of CNTs while maintaining the electronic properties of CNTs. The functionalization with Z-Gly-OH makes it possible to obtain amino groups on the surface of nanotubes in the absence of a solvent, while during this reaction it is possible to obtain intermediate functionalization in the form of benzyl carbamate, which can affect the sensitivity of sensors. In order to develop solid state device, Ti(8 nm)/Au(100 nm) interdigitated electrodes (IDEs) are fabricated on thermally oxidized Si substrate by using standard photolithography process. Dielectrophoresis is employed for deposition of as-functionalized SWNTs (f-SWNTs) between the IDEs. The gas sensing performance of as-developed is tested for NO2 gas as function of NO2 concentration (70 ppm to 20 ppm). As-developed gas sensor shows fast response/recovery (~ 88 s/95 s) as well as high sensitivity 27%. In order to analysed selectivity of as-developed gas sensor, the cross sensitivity has been observed for carbon monoxide (CO) and Methane (CH4). Before development of sensor, as-prepared f-SWNTs is analysed by SEM, Raman and FT-IR for its morphological and structural characteristics.

The diffractive optical element (DOE) for transforming of linearly polarized THz radiation beam into a cylindrically polarized beam is investigated. Optimal diffractive microrelief height is determined by numerical simulation.

Experimental results of the investigation of self-healing properties of terahertz Bessel beams with orbital angular momentum (OAM) with topological charges of l = 3 and l = 4 in free space after passing through a dispersive medium are presented.

Abstract Present article deals with microsystem technology and nanosensors. We covered the properties and synthesis technology of Carbon Nanomaterials. The detailed discussion has been made on synthesis of Carbon Nanotubes by thermal chemical vapour deposition (CVD) while reduced graphene oxide by modified Hummers method. Further, as grown Carbon nanomaterials have been used for developing optical detector for visible to near infrared range and Nitrogen Dioxide gas sensor.

The development and fabrication of broadband antireflection structures (ARS) for the THz frequency range are discussed. The three-level ARS was fabricated on a silicon substrate by RIE technology (Bosch-process). Results of realized ARS spectral investigation are presented.

The propagation length of surface plasmon polaritons (SPPs) increases with wavelength, which makes it possible to use radiation from the far-infrared and terahertz ranges to create communication devices employing SPPs as carriers of information. In this paper, we consider methods for implementing the multiplex transmission of information along cylindrical conductors using a combination of SPPs with orbital angular momentum and present experimental setups for the experiments on the Novosibirsk free electron laser.

Diffractive optics technologies are opening up new possibilities for power terahertz laser radiation controlling. Silicon diffractive optical elements are used for focusing of a terahertz laser beam into pre-given domains, for forming beams with needed transverse mode content, as well as for terahertz beam polarization transforming.

The paper is devoted to investigation of forming multimode coherent beams of terahertz radiation with pre-given transverse mode content and terahertz vector beams by use of silicon diffractive optical elements forming single modes from terahertz free-electron laser illuminating beam.

A silicon subwavelengh terahertz axicon has been designed, fabricated, and investigated by methods of numerical and optical experiments. The research has been performed on a free-electron laser workstation NOVOFEL (Budker Institute of Nuclear Physics of SB RAS, Novosibirsk). Diffractive and polarization features of realized element have been investigated.

— A three-layer structure is fabricated on a low-resistance silicon substrate using plasma chemical etching. We study it experimentally and show that a substrate with such a structure can be used as an absorber of terahertz (THz) radiation in the frequency range of 0.5−2.0 THz. For this structure, absorbance in the indicated frequency range is measured to be more than 95%.

Mode spatial multiplexing, has been shown for Gauss-Hermite and vortex beams in the THz spectral range. Transformation of a Gaussian TEM00 input beam of Novosibirsk Free Electron Laser was realized by silicon diffractive optical elements. Superposition of vortices with different topological charges has been examined A correlation filter was applied for mode analysis.

Novosibirsk free electron laser is a tunable source of radiation generating high-power Gaussian beams in MIR, FIR and THz spectral ranges. In this paper we report the transformation of terahertz beams into the beams with prescribed cross-sections and phase distributions, including vector and vortex beams, using diffractive optical elements. Examples of the use of such beams in experiments are given in the paper.