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• STUDY OF THE PROPAGATION OF LIGHT WITH A WAVELENGTH OF 1.3 ΜM IN TWO-DIMENSIONAL GaAs-BASED PHOTONIC CRYSTALS WITH A WAVEGUIDE–MICRORESONATOR CONFIGURATION

  Maximilian Pleninger , S.V. Balakirev , М.S. Solodovnik

  133-142

  2025-11-10

  Abstract ▼

  Photon crystals are semiconductor structures characterized by a periodic variation of dielectric permittivity in space with a period comparable to the wavelength of electromagnetic radiation. Interest in these structures is driven both by the importance of fundamental research into light-matter interactions and by the prospects for applying photonic crystals in optical integrated circuits and next-generation optoelectronic components. This paper presents the results of a study on the propagation patterns of electromagnetic radiation with a wavelength of 1.3 μm in two-dimensional photonic crystals based on gallium arsenide (GaAs). The research is based on a numerical model using the Comsol Multiphysics 6.1 software package and includes an analysis of the electric field intensity distribution in complex photonic crystal structures consisting of a waveguide coupled to a hexagonal microcavity (microresonator) with various geometric parameters. The influence of a deliberately introduced defect radius in the waveguide region on the efficiency of radiation transmission into the resonator area also analyzed. For numerical analysis, methods for simulating the propagation of transverse electric waves in two-dimensional photonic crystals with a hexagonal lattice of air holes employed. The geometric parameters of the basic photonic crystal structure remained constant: the air hole radius was 209 nm, and the lattice period was 520 nm. The waveguide was formed by removing one row of air holes, while the microresonator was created by forming a hexagonal air cavity near the waveguide. To enhance the coupling efficiency between the waveguide and resonator, a defect in the form of an air hole with a variable radius was introduced into the structure. Analysis showed that maximum localization of the electromagnetic field in a hexagonal cavity with a diameter of 1.65 μm was achieved when the cavity was positioned two rows of air holes away from the waveguide. Increasing this distance resulted in a reduction of field intensity within the resonator. Introduction of the defect significantly enhanced energy transfer efficiency from the waveguide to the resonator. The highest integral electric field intensity in the resonator region was observed when the defect radius ranged from 246 to 290 nm. The obtained data can be used in the development of compact optical devices such as lasers, modulators, and switches based on photonic crystals

• SIMULATION OF THE ELECTRIC FIELD STRENGTH DISTRIBUTION IN AN ALL-OPTICAL LOGIC COMPARATOR BASED ON THE GaAs PHOTONIC CRYSTAL

  М. Pleninger, S.V. Balakirev, М.S. Solodovnik

  2024-11-10

  Abstract ▼

  Photonic crystals, semiconductor structures with a photonic band gap, are of great interest to the
  scientific community. They represent a new class of optical materials with spatial periodic modulation of
  permittivity with a period close to the wavelength of radiation. Interest in these structures is explained by
  their importance for fundamental studies of the interaction of radiation with matter and the potential for
  creating next-generation optoelectronic devices. This paper presents the results of modeling a compact
  optical logic comparator based on a GaAs photonic crystal operating in the second transparency window
  of an optical fiber (wavelength of 1.3 μm). The model comparator is a medium with two input and two output optical channels. When radiation is input to one of the comparator inputs, the corresponding output
  channel transmits radiation, indicating a logical one. In the absence of signals on the input channels
  or when signals are input to both input channels, both output channels do not transmit radiation, indicating
  logical zeros. The channels in the comparator are created using intersecting waveguides formed in a
  two-dimensional GaAs photonic crystal, which consists of a set of cylindrical GaAs crystals (pillars) with
  a diameter of 130 to 170 nm, embedded in a vacuum medium with a period of 450 to 750 nm. To ensure
  attenuation of electromagnetic waves introduced into the comparator in both input channels, defective
  GaAs pillars with a smaller diameter are embedded at the intersection of the waveguides. The influence of
  the diameter and period between the GaAs photonic crystal pillars on the propagation patterns of electromagnetic
  radiation in the optical comparator medium is studied. Based on the analysis of the ratio of
  signal intensity levels at the inputs and outputs of the device, it is established that the optimal diameter of
  the GaAs pillars and the distance between them, at which the structure best meets the requirements of the
  logic comparator, is 155 and 600 nm, respectively.

• INVESTIGATION OF THE INFLUENCE OF ANNEALING MODES OF THE GAAS(111) SURFACE ON THE CHARACTERISTICS OF NANOHOLES FORMED BY FOCUSED ION BEAMS AT VARIOUS EXPOSURE TIMES

  Е. А. Lakhina, N.Е. Chernenko, N. А. Shandyba, S.V. Balakirev, М.S. Solodovnik

  2025-01-14

  Abstract ▼

  The paper presents the results of experimental studies of the processes of formation of holes by the
  method of focused ion beams on GaAs(111) substrates and their subsequent transformation during annealing
  in an ultrahigh vacuum chamber of molecular beam epitaxy in an arsenic flux and in its absence.
  It was found that at an ion beam exposure time of 1 ms, the processes of ion accumulation in the substrate
  prevail over the processes of the material sputtering, whereas at an exposure time of 5 ms, intensive sputtering
  of the substrate material occurs at the points of exposure to the ion beam with an increase in the
  depth of the etched areas with an increase in the number of ion beam passes. After annealing of substrates
  with ion beam-modified areas, the holes increase significantly in size as a result of local droplet etching
  processes. Studies showed that the hole size after annealing in the arsenic flux exceeds the hole size after
  annealing in the absence of an arsenic flux in almost the entire range of the number of ion beam passes.
  The dependences of the depth and lateral size of the holes on the number of ion beam passes are nonmonotonic,
  due to the competition of the processes of droplet etching and crystallization of ion beammodified
  areas in the arsenic flux. The results of experimental studies show that to obtain highly symmetric
  pyramidal holes with low surface density, it is required to create on the GaAs(111) surface an array of
  focused ion beam treatment points with an interval of 2 μm at an exposure time of 5 ms and a number of
  passes equal to 40. At the next stage, it is necessary to transform the ion beam processing points into pyramidal-
  shaped holes by annealing the substrate in a molecular beam epitaxy chamber at a temperature
  of 600°C and a time interval of 60 minutes. The technique proposed in this work, based on the combination
  of ion-beam surface treatment and molecular beam epitaxy, makes it possible to obtain nanoholes
  with the required symmetry, which can further serve as nucleation centers for InAs quantum dots with the
  desired properties.