Diffraction characteristics of optical elements designed as phase layers with cosine-profiled periodicity in azimuthal direction

The article concerns an investigation of the Fresnel diffraction characteristics of two types of phase optical elements, under Gaussian laser beam illumination. Both elements provide an azimuthal periodicity of the phase retardation. The first element possess azimuthal cosine-profiled phase changes deposited on a plane base. The second element is a combination of the first element and a thin phase axicon. The cosine profile of the phase retardation, of both diffractive elements, produces an azimuthal cosine-profiled modulation on their diffractograms. It destroys the vortex characteristics of their diffraction fields.Comment: 20 pages, submitted for publishin

Optical elements based on silicon photonics

Silicon photonics is gaining substantial impulse because it permits optical devices to be realized inexpensively using standard semiconductor fabrication techniques and integrated with microelectronic chips. In this paper, we designed few optical elements such as optical power splitter, polarization beam splitter and Bragg grating based on silicon platform simulated using finite element method.This work was financially supported by the Russian Foundation for Basic Research (grant No. 16-29-09528_ofi_m) for numerical calculations, by the Ministry of Science and Higher Education within the State assignment FSRC "Crystallography and Photonics" RAS (No. 007-GZ/Ch3363/26) for theoretical results

Asymmetric apodization for the comma aberrated point spread function

This paper deals with the study of light flux distributions in the point spread function formed by an optical system with a one-dimensional aperture under the influence of the coma aberration. The traditional design of an asymmetric optical filter improves the resolution of a diffraction-limited optical imaging system. In this approach we explore the control of monochromatic aberrations through pupil engineering with asymmetric apodization. This technique employs the amplitude and phase apodization for the mitigation of the effects of third-order aberrations on the diffracted image. On introducing the coma wave aberration effect, the central peak intensity in the field of diffraction is a function of the edge strips width and the amplitude apodization parameter of a one-dimensional pupil filter, whereas the magnitude of the reduction of optical side-lobes is a function of the degree of phase apodization at the periphery of the aperture. The analytically computed results are illustrated graphically in terms of point spread function curves under various considerations of the coma aberrations and a different degree of amplitude and phase apodization. Hence, for the optimum values of apodization, the axial resolution has been analyzed using well-defined quality criteria.This work was partially financially supported by Ministry of Education and Science of Russian Federation and Russian Foundation for Basic Research (RFBR) (16-29-11698, 16-29-11744)

A compact design of a balanced 1×4 optical power splitter based on silicon on insulator slot waveguides

In this paper, a compact design of a balanced 1×4 optical power splitter based on coupled mode theory (CMT) is presented. The design consists of seven vertically slotted waveguides based on the silicon-on-insulator platform. The 1×4 OPS is modelled using commercial finite element method (FEM) simulation tool COMSOL Multiphysics 5.1. The optimized OPS is capable of working across the whole C-band with maximum ~39 % of power decay in the wavelength range 1530 – 1565 nm.This work was partially financially supported by Ministry of Education and Science of Russian Federation, Russian Foundation for Basic Research (RFBR) (16-47-630677, 16-29-11744) and by the Federal Agency for Scientific Organizations (agreement No. 007-G7/C3363/26)

Modeling of a Cold mirror based on TiO2/MgF2 and TiO2/SiO2 at 45o angle of incidence

In this paper, a modeling of a multilayer dielectric cold mirror based on TiO2/SiO2 and TiO2/MgF2 alternating layers is presented. A cold mirror is a specific dielectric mirror that reflects the complete visible light spectrum whereas transmitting the infrared wavelengths. These mirrors are designed for an incident angle of 45o, and are modeled with multilayer dielectric coatings similar to interference filters. Our designed mirror based on TiO2/SiO2 shows an average transmission of less than 5% in spectrum range of 425-610 nm whereas it has an average transmission of 95% in the spectrum range of 710-1500 nm.This work was supported by the Ministry of Education and Science of the Russian Federation and the Russian Foundation for Basic Research (grants No. 16-07-00825, 16-26-11698-ofi_m)

Modeling of a multilayer dielectric stack Notch filter for visible spectrum

In this work, a multilayer dielectric optical notch filters design for visible spectrum 450-700 nm is proposed based on TiO2 and SiO2 alternating layers. Titanium dioxide (TiO2) is selected for its high refractive index value (2.5) and Silicon dioxide (SiO2) as a low refractive index layer (1.45). These filters are conventionally anticipated for overpowering of powerful laser beams in research experiments, to obtain good signal-to-noise ratios in Raman laser spectroscopy. The designed filter shows a high quality with average transmission of more than 90% in 450-535 and 587-700 nm wavelength ranges. And a stop band region between 536-586 nm with a FWHM of 50 nm shows a transmission of 3% with an optical density of greater than 3, which makes it a promising element to be used as notch filter.This work was supported by the Ministry of Education and Science of the Russian Federation and the Russian Foundation for Basic Research (grant No. 16-47-630546)

Conditions of a single-mode rib channel waveguide based on dielectric TiO2/SiO2

In this paper, we propose conditions for the design of a single-mode rib channel waveguide based on dielectric materials such as titanium dioxide (TiO2) and silicon dioxide (SiO2) for the 0.633-µm visible light. We also design Y-splitter structures, which show high-degree optical confinement and low bend losses at various radii of curvatures. Small radii of curvatures are extremely desirable in integrated photonics as they permit decreasing the dimensions but can also potentially reduce power consumption in the active devices.The work was partially funded by the RF Ministry of Education and Science (# SP-4375.2016.5), a RF President's grant for support of leading scientific schools (# NSh-9498.2016.9) and RFBR (##17-47-630420, 17-47-630417, 16-47-630483, 15-07-01174)