Optoelectronic Equipment Research Articles

Materials for semiconductor nanowires in nanoscale photonic and electronic devices

Abstract Many aspects of civilization are impacted by electronic and optoelectronic equipment, including medical instruments, communications, computing, multimedia systems, and basic home appliances. the development of nanoscale devices has garnered significant attention due to the increasing demand for smaller, more powerful, and efficient systems across various industries. Nanoscale devices operate at the nanometer scale, typically involving structures and components with dimensions on the order of 1 to 100 nanometers. As a potent class of materials, semiconductor nanowires are creating a lot of new possibilities for innovative nanoscale photonic and electrical devices through carefully regulated development and organization. the exploration of electronic and optoelectronic nanodevices, along with integrated arrays, opens up a rich landscape of possibilities across various technological domains. This research not only pushes the boundaries of miniaturization but also paves the way for innovative applications in electronics, photonics, sensing, and emerging fields like quantum and neuromorphic computing that hold the potential for numerous applications in the future.

A holistic approach of strain-induced and spin-orbit coupling governed structural, optical, electrical and phonon properties of Janus MoSSe heterostructure via DFT theory

Spintronics and optoelectronic equipment benefit from efficient modification of electrical and optical characteristics for Van der Waals heterostructures. Janus MoSSe, in two dimensions, has superior electronic, optical, and phonon properties. Based on these characteristics, we evaluate the effects of biaxial compressive and tensile strain ranges of −6% to +6% on the structural, optical, spin–orbit coupling, and phonon properties of two-dimensional MoSSe employing first-principles-based density functional theory calculations. At K-point, MoSSe possesses a direct band gap of 1.665 eV, making it a semiconductor. Yet, applying tensile strain, we can observe that the bandgap of MoSSe has declined. On the other hand, the bandgap of MoSSe rises due to the compressive strain. From the phonon properties, it is clear that the stability of the monolayer MoSSe is observed in the case of tensile strain. With the increase of compressive strain, it loses its stability. With a photon energy of 2.5 eV, MoSSe exhibits three times greater optical absorption than other photon energy levels. In comparison to two monolayers (MoS2, MoSe2), the MoSSe heterostructure shows an elevated optical absorption coefficient in the visible light band, according to our calculations of its dielectric constant and optical absorptionThe MoSSe dielectric constant’s peaks shift to the stronger photon energy as compressive strain is increased; in contrast, if tensile strain is added, the highest points shift to the less powerful photon energy. This suggests that the spin–orbit coupling (SOC) in MoSSe heterostructures can be enhanced under strain, which has implications for spintronics. The effect of strain can be used to tailor the phonon behaviors of MoSSe, which can be useful for controlling the material’s mechanical and thermal characteristics. The versatility of the electronic and optical properties of the material under strain can be harnessed to design novel devices such as strain sensors, optoelectronic modulators, and detectors.

A DFT study of structural, electronic, mechanical, optical, and hydrogen storage properties of quaternary hydride phase Li4BN3H10

In this paper, we investigated the structural, electronic, mechanical and optical properties of Li4BN3H10 using the ultra-soft pseudopotential method which is based on the density functional theory (DFT) with CASTEP code. The optimized lattice parameters of Li4BN3H10 correlate well with the theoretical calculations and experimental measurements that are currently available. Using elastic constants, the material's stability was verified. Based on the elastic constants, we discovered several mechanical features of the material. Between 0 and 20 eV, optical spectra calculations are made, taking into account the real and imaginary parts of the dielectric function ε(ω), reflectivity R(ω), index of refraction n(ω), coefficients of extinction k(ω) and absorption α(ω). The dielectric function is wide close to the middle ultraviolet (4.13–6.20 eV). The extinction coefficient of the Li4BN3H10 has the ability to worn for implements like Bragg's reflectors, optical and optoelectronic equipments. The optical parameters of Li4BN3H10 disclose that our working constructions have an elevated dielectric constant, with a greatest absorption in the visible range holding out over 1.49 × 105 cm−1 Li4BN3H10 is deemed to be an appropriate material for optoelectronic applications based on calculated optical results. The gravimetric hydrogen storage capacities of Li4BN3H10 compound is 11.06 wt %. These promising capacities exceed the 6.5 wt % target set by the US Department of Energy for 2025.

Random lasing in dye-doped electrospun PMMA fibers with different emission modes

Random lasers (RLs) have significant applications in micro-nano light emitters, micro-detection, and speckle-free imaging due to their novel properties in low spatial coherence, small size and multi-emission directions. A flexible, affordable approach for creating new scattering materials has recently been suggested for electrospun fibers, which are practical materials for RLs. In this article, we employ the electrospun PMMA fibers as scatters and the DCJTB as gain materials to generate an RL system. The sample shows obvious incoherent random lasing properties. A decrease of the lasing threshold by 32 % is realized when we increase the electrospun voltage from 12 kV to 15 kV due to the generation of a small mean diameter size and concentrated diameter distribution. The lasing threshold of the DCJTB/Au NPs-doped PMMA sample is further reduced to 19.8 μJ/mm2 by incorporating Au NPs into the electrospun dye-doped fibers. This leads to a lasing threshold reduction of 40 % from the electrospun sample without doping Au NPs and 52 % from the spin-coated film sample, respectively. It indicates that the electrospun method is an efficient and practical approach to make RLs. Furthermore, using single pulse laser stimulation, we investigated several different lasing modes, including spontaneous emission, short wavelength domain, mode competition, and single mode. The actions of photon scattering are analyzed to explain the dramatic lasing process. Due to the photon scattering optical path, there are mode competition and single mode emission regions under different pump energy. The light spot quality of RL shows low spatial coherence with the useful application of speckle-free imaging. This research provides a new method of electrospun to produce low-threshold and high-quality RLs and potentially opens the door for expanding their use in optics and optoelectronic equipment.

Vacuum large-aperture black body model in the temperature range of 223.15–423.15 K for radiometric calibration of optoelectronic equipment for earth observations

Vacuum large-aperture black body model in the temperature range of 223.15–423.15 K for radiometric calibration of optoelectronic equipment for earth observations

Bubble-Induced Strong Thermal Contraction for Graphene

Abstract The thermal expansion coefficient (TEC) of van der Waals (vdW) layered structures is of crucial importance in governing the dependability and longevity of advanced optoelectronic equipment. Bubbles are commonly found within layered structures, yet their impact on the thermal expansion coefficient of the structure is still not well understood. We derive an analytical formula that describes the influence of bubbles on the variation in length, utilizing both the elastic membrane theory and the improved van der Waals gas state equation. The results demonstrate that as the temperature increases, bubbles can induce significant thermal contraction in few-layer graphene structures. The analytical predictions are validated through molecular dynamic (MD) simulations, confirming the accuracy and reliability of the proposed model. These findings hold significant value in enhancing our understanding of the dependability and durability of functional equipment that relies on van der Waals layered structures.

PEG’s impact as a plasticizer on the PVA polymer’s structural, thermal, mechanical, optical, and dielectric characteristics

An array of water-soluble polymer blends composed of polyvinyl alcohol (PVA) and polyethylene glycol (PEG) have been synthesized by the solution casting technique. The prepared blends were tested using X-ray diffraction (XRD), differential scanning calorimetry, mechanical, optical, and dielectric measurements. According to the XRD studies, PEG has a significant plasticizing impact on PVA, as evidenced by the drop in crystallinity (Xc) values from 31.24 to 25.45%. The thermal study reveals the reduction in the glass transition temperature Tg from 89.2 to 60.6 °C. The outcomes showed that adding PEG affects the mechanical characteristics of PVA/PEG blends, and the ideal blend was one with 25 wt% of PEG loading, where the value of the percentage elongation at break (78%), Toughness (0.44) and surface energy (0.076) reached the highest values at this blend. Meanwhile, Young's modulus declined from 20.34 MPa for pure PVA to 7.07 MPa at 25 wt% PEG. According to the optical studies, the absorption edge shifted from 5.24 to 4.26 eV while the optical band gap ({{E}_{g}}^{ind}, {{E}_{g}}^{d}) decreased from 4.81, 5.46 eV (pure PVA) to 3.77, 5.04 eV (PVA/PEG30%) respectively, which indicates that forming charge transfer complexes between PVA and PEG polymer. The EU values enhanced from 0.238 to 1.296 eV and the refractive index improved from 1.38 to 2.97 when PEG content increased. The dielectric and conduction properties were studied from 100 Hz to 1 MHz. It was demonstrated that the dielectric constant ({varepsilon }{prime}) and dielectric loss ({varepsilon }{prime}{prime}) are highly frequency-dependent. In addition to that, ({varepsilon }{prime}, {varepsilon }{prime}{prime}) values improved from (30, 2) for PVA to (44.46 and 5.39) for PVA/30 wt% PEG blend at 100 Hz, respectively. At the same time, the AC electrical conductivity is improved by increasing the PEG content. These results will likely have far-reaching consequences across a variety of fields, the possible applications due to the increased flexibility of PVA film are flexible packaging, biomedical materials, and other industries that need adaptive and flexible materials. Furthermore, the improved refractive index of the PVA/PEG combination demonstrates its appropriateness for certain applications such as optoelectronic equipment, waveguides, anti-reflective coats, and LEDs. This blend has uses in charge storage devices, such as embedded capacitors due to the enhancement of dielectric constant. Finally, one can say that the research samples have multifunctional applications.

Vacuum large-aperture blackbody model in the temperature range 223.15–423.15 K for radiometric calibration of optoelectronic equipment for Earth observation

The structure of the systems for the radiometric calibration of the remote sensing optoelectronic equipment in the infrared spectral range is presented. The analysis of existing facilities for the radiometric calibration of the remote sensing optoelectronic equipment in conditions of vacuum and low-background radiation was carried out. These facilities are based on using of the blackbody models as radiation sources, including reference sources based on the phase transition of pure metals, for example gallium or indium. The wide-aperture blackbody model LABB-380 with an aperture diameter of 380 mm in the temperature range from 223.15 K up to 423.15 K has been developed for a high-vacuum low-background stand, which is currently being developed at the Sciences Research Institute of Optoelectronic Instrumentation for the radiometric calibration of the remote sensing optoelectronic equipment. The results of calculating the normal effective emissivity of the surface of the LABB-380 in the temperature range from 223.15 K to 423.15 K in the spectral range from 3 to 20 μm are presented. The metrological characteristics of LABB-380 obtained during the transmission of a temperature unit from the zero discharge State Standard using a comparator based on the precision pyrometer HETRONIXS are investigated and presented. The instability of the LABB-380 radiation was 0.005 K according to the calibration results in the temperature range from 300.15 K to 390.15 K, and the extended temperature uncertainty was 0.66 K at the temperature of 300.15 K and 0.88 K at a temperature of 390.15 K.

Self-driven Vis-NIR broadband photodetector based on nano-hedge-like MoS2/WSe2 heterostructure

TMDC heterostructures provide alternative bases for optoelectronic devices besides conventional Schottky devices. With the continued expansion of the modern semiconductor industry, self-powered devices have emerged as an integral part of electronic and optoelectronic equipments. This work reports a unique seamless nano-hedge (nh) like morphology of MoS2 deposited on WSe2 film to form nh-MoS2/WSe2 heterostructure as a self-powered photodetector with a broad spectral range from visible to NIR. The developed heterostructure exhibits a very high responsivity of 900 mAW-1 when illuminated by 860 nm under zero bias (self-powered mode). In addition, the device also shows a high responsivity of 177 mAW-1, 271 mAW-1, and 506 mAW-1 for illumination of 532 nm, 625 nm light, and 950 nm, respectively, at zero applied bias. With low noise equivalent power of 2.6 × 10-14 WHz1/2 and ultra-high responsivity of 2.6 × 104 mAW-1 in photoconductive mode at 860 nm light irradiation, the device exhibits extremely high external quantum efficiency of 6.29 × 103%. Further, the device also displays detectivity of 5 × 1011 Jones, an LDR value of 26 dB, with a fast response time of 15 ms. Developing a broadband photodetector based on nh-MoS2/WSe2 heterostructure opens the route for highly responsive, self-powered future optoelectronic devices.

Thermal characteristics of latent heat sinks based on low melting point metal and topologically optimized fins under lateral hypergravity

With the increasing thermal load of optoelectronic equipment on aircraft, the method of using low melting point metals (LMPMs) instead of organic phase change materials (PCMs) to construct latent heat sinks has immense potential to solve the thermal control problem. However, aircraft are usually under hypergravity during maneuvering flight, and the thermal characteristics of latent heat sinks are likely to be different from those under normal gravity. Hence, the dynamic thermal characteristics of a latent heat sink with bismuth-based LMPM and topologically optimized fins under lateral hypergravity (0–6 g) were investigated with heat fluxes of 10–50 kW/m2. Compared with n-docosane, LMPM decreases the heating wall temperature by over 10 °C, and the holding time below specified temperatures (50, 60, and 70 °C) is prolonged by more than 50 %. Compared with the pin fin, the topologically optimized fin reduces the heating wall temperature by more than 4 °C maximum. The effect of hypergravity on the thermal performances of the heat sink with LMPM and topologically optimized fins is connected with the melting stage. It is negligible in the solid conduction stage and the initial stage of latent melting. It makes the heating wall temperature first increase and then decrease but always higher than that under normal gravity in the rest stage of latent melting. It causes the heating wall temperature to monotonically decrease with hypergravity in the liquid convection stage. The largest difference in heating wall temperature under various gravity occurs between 2 g and 0 g. It is 5.2 °C and its percentage is 7.6 % for 50 kW/m2. In addition, the effect of heat flux on thermal performances is not related to hypergravity.

Theoretical Study on the Electronic Properties of Two-Dimensional Covalent Triazine Frameworks/As van der Waals Heterostructures

The manuscript substantiates the structural and electronic properties of covalent triazine frameworks (CTF)/As van der Waals heterostructures (vdWh) employing the standard first-principles calculation method. The numerical results designate that the CTF/As vdWh has robust crystal structures, a type-II band alignment (BA), and an indirect bandgap of 1.44 eV. The calculated results demonstrate that the strain could lead to interesting indirect-direct semiconductor transitions, while the external electric field could give rise to type-II to type-I BA and semiconductor-metal transitions. The underlined outcomes present the workability of CTF/As vdWhs in unprecedented high-performance optoelectronic equipment.

Nanobubble-induced significant reduction of the interfacial thermal conductance for few-layer graphene.

The heat transport properties of van der Waals layered structures are crucial for ensuring the reliability and longevity of high-performance optoelectronic equipment. Owing to the two-dimensional nature of atomic layers, the presence of bubbles is commonly observed within these structures. Nevertheless, the effect of bubbles on the interfacial thermal conductance remains unclear. Based on the elastic membrane theory and the improved van der Waals gas state equation, we develop an analytical formula to describe the influence of bubble shape on the interfacial thermal conductance. It shows that the presence of bubbles has a considerable impact on reducing the interfacial thermal conductance across graphene/graphene interfaces. More specifically, the presence of nanobubbles can result in a reduction of up to 53% in the interfacial thermal conductance. The validity of the analytical predictions is confirmed through molecular dynamic simulations. These results offer valuable insights into the thermal management of van der Waals layered structures in the application of next-generation electronic nanodevices.

Analysis and Experimental Research on Dynamic Characteristics of Horizontal Shaft System of Photoelectric Equipment

In order to study the transmission characteristics of vibration in the shafting of optoelectronic equipment, a horizontal shafting test platform for optoelectronic equipment is designed. Firstly, according to the special structure and load conditions of the three-row ball-column combined turntable bearing used in the horizontal shafting, a quasi-static model of the bearing load was established to solve the load distribution of the bearing and further calculate the bearing stiffness. At the same time, the bearing system was established. The dynamic model of the system is used to calculate the frequency response function of the system under the conditions of radial load and axial load and analyze the vibration transmission characteristics of the shaft system. Based on the finite element method, a finite element calculation model is established, the shafting dynamic model established is used to simplify the bearing, the modal parameters of the equipment are analyzed, and the experimental verification is carried out using the Siemens dynamic test system. The results show that the established model is effective and reliable. It provides a reference for studying the dynamic characteristics of the shaft system of optoelectronic equipment.

Electron donor–acceptor (D-A) tuning to achieve soluble covalent organic polymers for optoelectronic devices

Covalent organic polymers (COPs) have emerged as a unique class of luminescent polymers with pre-designed quasi-ordered architectures. However, their layered stacks and limited solubility preclude further processing for large-scale applications in devices, especially optoelectronic equipment. Herein, a universal strategy to adjust the electron donor–acceptor (D-A) moieties of the building blocks in COPs is proposed, achieved by in situ charge exfoliation of COP blocks into few-layer true solutions in (Lewis) acid and base media. The electron D-A moieties of the building blocks endow the COPs with the ability to accept or donate electrons, by altering the electron cloud distribution as well as the relative energy levels of the frontier molecular orbitals. The resultant soluble COPs can easily be processed into a uniform film by solution processing via the spin-coat method. The obtained COP-N achieves efficient and stable perovskite electroluminescence as a novel hole injection material on indium tin oxide, and the operating lifetime for a perovskite quantum dot light-emitting diodes device exceeds that of a poly(ethylene dioxythiophene):polystyrene sulphonate counterpart. This straightforward electronic regulation strategy provides a new avenue for the rational synthesis of processable reticular molecular polymers for practical electronic devices.

Infrared Small-Target Detection Based on Radiation Characteristics with a Multimodal Feature Fusion Network

Infrared small-target detection has widespread influences on anti-missile warning, precise weapon guidance, infrared stealth and anti-stealth, military reconnaissance, and other national defense fields. However, small targets are easily submerged in background clutter noise and have fewer pixels and shape features. Furthermore, random target positions and irregular motion can lead to target detection being carried out in the whole space–time domain. This could result in a large amount of calculation, and the accuracy and real-time performance are difficult to be guaranteed. Therefore, infrared small-target detection is still a challenging and far-reaching research hotspot. To solve the above problem, a novel multimodal feature fusion network (MFFN) is proposed, based on morphological characteristics, infrared radiation, and motion characteristics, which could compensate for the deficiency in the description of single modal characteristics of small targets and improve the recognition precision. Our innovations introduced in the paper are addressed in the following three aspects: Firstly, in the morphological domain, we propose a network with the skip-connected feature pyramid network (SCFPN) and dilated convolutional block attention module integrated with Resblock (DAMR) introduced to the backbone, which is designed to improve the feature extraction ability for infrared small targets. Secondly, in the radiation characteristic domain, we propose a prediction model of atmospheric transmittance based on deep neural networks (DNNs), which predicts the atmospheric transmittance effectively without being limited by the complex environment to improve the measurement accuracy of radiation characteristics. Finally, the dilated convolutional-network-based bidirectional encoder representation from a transformers (DC-BERT) structure combined with an attention mechanism is proposed for the feature extraction of radiation and motion characteristics. Finally, experiments on our self-established optoelectronic equipment detected dataset (OEDD) show that our method is superior to eight state-of-the-art algorithms in terms of the accuracy and robustness of infrared small-target detection. The comparative experimental results of four kinds of target sequences indicate that the average recognition rate Pavg is 92.64%, the mean average precision (mAP) is 92.01%, and the F1 score is 90.52%.

APPLICATION OF THREE-WAVE HETERODINE INTERFEROMETRY FOR NANORIZED LAYERS THICKNESS MEASUREMENT IN THE PROCESS OF THEIR DEPOSITION

The paper proposes a new method of current measurement of the layer thickness of optical films in the process of their forming, in particular, by the method of vacuum deposition. Such films, among other things, are used to create a variety of optoelectronic devices and optical nanosensors for laboratory research in the chemical and pharmaceutical industries, for environmental monitoring.
 We propose a method for measuring the phase of a laser beam, which is based on heterodyne interferometry. The method of heterodyne interferometry in comparison with ordinary interference methods provides better S/N ration results due to the transfer of the investigated signal from the low frequency domain to heterodyne frequency. Our proposed approach is the three-wave heterodyne interferometry (TGI), otherwise - TWI (three waves interference). The TGI method is designed to critically increase the sensitivity to small amplitudes of laser Doppler vibrometers and increase their noise resistance. In interference gauges of optical film thickness, in refractometers, and in many other film thickness gauges as well as in laser Doppler vibrometers the investigated parameter is the phase shift of probing optical radiation. Therefore, the developments of TGI in laser Doppler vibrometers can be used to measure the phase shift.
 The analysis of the new method on mathematical model of TGI was provided. We have got the relations of the output signal of a three-wave heterodyne interferometer dependence on the phase shift , as well as on the thickness of optical films and on their refractive index. The simulation results show that for the optoelectronic equipment that provides with an error of up to 10 %, the absolute error of phase shift measurement, compared to the classical heterodyne interferometer, can be reduced to 103 times. The same results applies to the thickness of the optical coating layer.
 The paper also analyzes the results of experiments on the use of TGI in laser vibrometers and shows that they indicate the possibility of measuring the phase of optical radiation up to 10-5. The disadvantage of the proposed method is its non-linearity and, as a result, a limited linear range. Ways of extending the linear range are discussed.

Enhanced photoelectric responsivity of bilayer graphene/GaAs photodetector using plasmon resonance grating structures

High-efficiency integrated photodetectors are the core supporting components for the miniaturization of optoelectronic equipment. The design of a grating structure on the surface of bilayer p-graphene/n-GaAs can excite a plasmon mode to enhance the photoelectric performance of photodetectors. Here, we simulate a heterojunction photodetector which is highly sensitive to wavelengths ranging from 550 nm to 850 nm to evaluate the optical and electrical performance of the grating/graphene/GaAs structure. Such a high performance is attributed to the efficient carrier separation and transfer between graphene and GaAs, which is created by the strong electromagnetic field produced at the heterojunction area. The results indicate that through sophisticated design, heterojunctions using plasmon resonance can become potential candidates for various essential electronic and optoelectronic applications.

Thermal optics of a collimator radiatively cooled under vacuum

Infrared optoelectronic equipment with cooled optics operating in a background limited mode is tested in a vacuum and a low radiation background. The latter is ensured by cooling the optical elements of the collimator and preventing direct illumination of the entrance pupil of the equipment by warm elements of the vacuum chamber. Subject of study. The thermal optics of a two-mirror collimator are investigated in this study. The mirrors of this collimator are cooled by heat transfer through infrared emission to the cooled cylindrical shields of the thermostat, which was specifically designed for collimator cooling. Method. The collimator cooling modes are calculated considering both thermophysical material properties and structural features of the elements comprised in the thermostat and collimator. The thermophysical model of thermal equilibrium in an isolated system of solid bodies is used in the calculations. The issue of selecting a particular material for the collimator mirrors is considered provisionally. The thermal stability of the mirror material calculated as a ratio of the coefficient of thermal expansion β to its heat conduction coefficient λ is used as a parameter determining the choice. Sitall, silicon, and silicon carbide were considered in this study as materials for infrared mirrors. Main results. The magnitude of thermal deformations is determined by not only the occurring temperature gradients in a plane mirror but also the variation in the curvature of the mirror surface under general cooling of the nonplanar mirrors. The maximum temperature gradient over the surface is observed for the mirrors composed of sitall. The temperature gradient in the mirror composed of silicon carbide is significantly smaller. This is related to the heat conduction coefficient of silicon carbide being 2 orders of magnitude higher than that of sitall. Consequently, the thermal deformations of the mirror surface are also smaller in the plane mirror composed of silicon carbide. These results correspond to the criterial parameter of thermal stability β/λ for each of the discussed materials. However, in the case of cooling of the nonplanar (spherical or aspherical) mirrors, the calculations show that their thermal deformations result from not only the nonuniformity of heat flow distribution over the mirror surface but also the general reduction in mirror temperature. Practical significance. When cooled infrared mirrors are used in optical systems, the appearance of thermal deformation of their mirror surface should be considered. This thermal deformation is determined by not only the occurring temperature gradients in the volume of the mirror material, but also the change in the curvature of the mirror surface. In this regard, the mirrors composed of sitall are preferable for use under thermal vacuum conditions over mirrors composed of silicon carbide.

First-principles insights into Cs/NF3 co-activation effects on near-infrared In0.53Ga0.47As (0 0 1) surface

For InxGa1-xAs photocathodes, the negative electron affinity characteristics can often be obtained by adsorbing Cs/O or Cs/NF3. Moreover, the physical mechanism of the Cs/O adsorbing system has been extensively investigated, but for the Cs/NF3 adsorbing system, it is currently unclear yet. In this disquisition, the effect of Cs/NF3 co-adsorption on the In0.53Ga0.47As (001) β2 (2 × 4) surface was studied based on the density functional theory (DFT) calculation. The upshots manifest that NF3 molecule is beneficial to enhance the stability of the Cs covered In0.53Ga0.47As (001) β2 (2 × 4) surface. Besides, the newly generated dipole named [Cs–NF3] is beneficial to resist the depolarization phenomenon induced by excessive Cs adatoms. Therefore, it is conducive to the monotonically decreasing of surface work function, which is of great significance to enhance the performance of optoelectronic equipment. Also, the co-adsorption of Cs/NF3 changes the reflectivity and absorption coefficient of In0.53Ga0.47As (001) β2 (2 × 4) surface, which affects the photoelectric conversion efficiency of the photoemitter.

THEORETICAL FUNDAMENTALS OF THE CALCULATING THREE-MIRROR DECENTER ANASTIGMATS METHODOLOGY

The article is devoted to the theory of calculating mirror systems with anastigmatic properties, namely, the area of research in terms of developing methods for parametric calculation of dimensions and aberration correction. The such systems can correct three third-order aberrations. Mirror anastigmats allow developing the angular field of view of devices while maintaining a high numerical aperture, which allows them to be used in optoelectronic equipment operating in a wide spectral range. Complete absence of chromatic aberrations, high resolution, permissible wave criteria for image quality provide excellent opportunities for using mirror anastigmatic systems. General methodological approaches have been developed that can be applied to the creation of detailed engineering and technical methods for calculating a group of mirror anastigmatic systems. A serious drawback of reflective optics is center without central screening, which degrades image quality. To eliminate it, rotations or displacements of the mirrors are intro-duced, but non-elementary aberrations of even orders appear, which must be corrected. The creation of compositions with decentered catoptric elements requires further development of the calculation and methodological base. Mathematical solutions to the problem of creating basic models of non-centered mirror systems are presented. Accurate formulas are obtained for the calculation of real rays from the conditions of astigmatism and coma correction for the given angles of incidence of the chief ray on the mirror surfaces and the «oblique» thickness , which determines their relative position. Based on the proposed formulas, a new method for parametric calculation of decentered mirror systems has been created, which allows one to compose algorithms and design both basic models and complex mirror systems from off-axis mirrors. The development of new algorithms for two- and three-mirror decenter lenses will increase the accumulated potential of computational optics. The scope of the proposed technique can be expanded in terms of the number of components.