RU202291U1 - Scanner "photonic jet" in the microwave and EHF ranges - Google Patents

Abstract

The utility model relates to microwave and EHF technology, including the terahertz wavelength range, and can be used in various near-field vision systems, non-destructive testing with electronic scanning by the radiation focusing area and, in particular, in devices that allow deflecting a photon jet formed in microwave and EHF electromagnetic radiation scanning devices are one of the main elements of photonics. Devices for scanning with electromagnetic radiation, including radiation in the terahertz and optical wavelength ranges, are used in systems for imaging objects with subwavelength resolution, including in a confocal microscope. The objective of this utility model is to obtain the ability to control the transverse position in space of the generated photon jet. 2 wp f-ly, 3 dwg

Description

The utility model relates to microwave and EHF technology, including the terahertz wavelength range and can be used in various near-field vision systems, non-destructive testing with electronic scanning by the radiation focusing area and, in particular, for devices that allow deflecting a photon jet formed in the microwave and EHF length ranges waves.

Electromagnetic scanning devices are one of the main elements of photonics. Devices for scanning with electromagnetic radiation, including radiation in the terahertz and optical wavelength ranges, are used in systems for imaging objects with subwavelength resolution, including in a confocal microscope.

A device for the formation of a photon jet with superresolution properties is known, consisting of a radiation source and a weakly absorbing dielectric particle with a diameter comparable to the wavelength of the incident radiation and located along the direction of propagation of radiation [Heints Yu.E., Zemlyanoye A.A., Panina E. TO. Comparative analysis of the spatial shapes of photonic jets from spherical dielectric microparticles // Optics of the atmosphere and ocean. 2012. T. 25, No. 5. S. 417-424]. When this dielectric particle is made in the form of a spheroid.

The photonic jet arises directly in the region of the shadow surface of dielectric microspherical particles, i.e. in the near diffraction zone - and is characterized by strong spatial localization and high intensity of the electromagnetic field in the focusing area. The length of the photon jet is of the order of several wavelengths of the radiation used, and the transverse dimensions are less than half the radiation wavelength.

Later, the possibility of obtaining photonic nanojets was studied for dielectric axisymmetric bodies, for example, elliptical nanoparticles [IV Minin, OV Minin. Quasi-optics: modern development trends - Novosibirsk: SGUGiT, 2015. - 163 p .; T. Jalalia and D. Erni. Highly confined photonic nanojet from elliptical particles // Journal of Modern Optics, Vol. 61, No. 13, 1069-1076 (2014)], multilayer layered inhomogeneous microspherical particles with a radial gradient of refractive index [Cesar Mendez Ruiz and Jamesina J. Simpson. Detection of embedded ultrasubwavelength-thin dielectric features using elongated photonic nanojets // 2 August 2010 / Vol. 18, No. 16 / OPTICS EXPRESS 16805], as well as hemispheres [Cheng-Yang Liu. Photonic nanojet shaping of dielectric non-spherical microparticles // Physica E 64 (2014), pp. 23-28.], Discs [B. Lukyanchuk, N.I. Zheludev, S.A. Maier, N.J. Halas, P. Nordlander, H. Giessenand T.C. Chong. The Fano resonance in plasmonic nanostructures and metamaterials. Nat. Mater. 9, 707-715 (2010); C-Y. Liu and C-C. Li. Photonic nanojet induced modes generated by a chain of dielectric microdisks. Optik 127, 267-273 (2016).], Cylinder-sphere [Jinlong Zhu and Lynford L. Goddard. Spatial control of photonic nanojets // Optics Express, Vol. 24, No. 26, 2016, 30445].

It was also found that photonic jets can be formed by asymmetric mesoscale dielectric particles, for example, a cube, a truncated sphere, a pyramid, a truncated pyramid, a prism, a three-dimensional hexagon, etc. [I.V. Minin and O.V. Minin. Diffractive optics and nanophotonics: Resolution below the diffraction limit, Springer, 2016 http://www.springer.com/us/book/9783319242514#aboutBook; V. Pacheco-Pena, M. Beruete, I.V. Minin and O.V. Minin. Terajets produced by 3D dielectric cuboids. Appl. Phys. Lett. 105, 084102 (2014); I.V. Minin, O.V. Minin and Geintz Y.E. Localized EM and photonic jets from non-spherical and non-symmetrical dielectric mesoscale objects: brief review. Annalen der Physik (AdP), May 2015 DOI: 10.1002 / andp.201500132; Yu. E. Geintz, A.A. Zemlyanov and E. K. Panina. Photonic Nanonanojets from Nonspherical Dielectric Microparticles. Russian Physics Journal 58, 904-910 (2015); Yu. E. Geints, A.A. Zemlyanov and E.K. Panina. Characteristics of photonic jets from microcones. Optics and Spectroscopy 119,849-854 (2015); I.V. Minin, O. V. Minin. Photonics of isolated dielectric particles of arbitrary three-dimensional shape - a new direction of optical information technologies // Vestnik NSU. Series: Information technologies. 2014, No. 4, S. 4-10]. In all known cases, the photon jet was formed along the optical axis of the dielectric particle.

There are various types of scanners (deflectors): optical-mechanical, electronic, electro-optical, electro-optical and microelectromechanical systems (MEMS) [Vyskub V.G. Possibilities and limitations of composite scanners // Questions of radio electronics, 2018, no. 5, p. 74-82; Measuring scanning devices / V.G. Vyskub, V.A. Kantserov, I.M. Koltsov and others, ed. B.S. Rozova. M .: mechanical engineering, 1980, 198 p.]. For example, there are known scanning devices in which the scanning element is a rotating mirror rhombus or a mirror pyramid with a spatial arrangement of the axis of rotation [UK Patent No. 1393535, cl. G 02 B 26/10, 1975; USSR author's certificate N 1628041, class. G 02 B 26/10, 1991; USSR author's certificate N 1582170, class. G 02 B 26/10, 1990].

A deflector is known based on two optical wedges rotating at different speeds located on the same optical axis [RF Patent 2650776, lidar complex, published 04/17/2018, bull. No. 11].

Known microwave deflector [RF Patent 1042113, microwave deflector, publ. 09/15/83, Bulletin No. 34], consisting of a ferrite plate, a magnetization coil, the axis of which coincides with the normal to the plane of the ferrite plate on which the sound exciter is fixed.

A sound exciter (for example, a piezoelectric transducer) creates a sound wave in the ferrite plate, which causes a periodic change in the refractive index, i.e. creates a refractive index grating. Microwave or EHF radiation deviates from the initial direction of radiation propagation due to diffraction by the refractive index grating.

All known types of scanners are large and are not designed to control the position of the photonic jet.

Known device acousto-optic deflector on bulk acoustic waves to control the parameters of laser radiation [RF Patent 2349945, Acousto-optic deflector, Published: 20.03.2009, bull. No. 8; RF patent 2355007, Method of two-coordinate deflection of optical radiation, published 05/10/2009, Bul. No. 13; D.P. Volik, V.V. Rozdobudko. Acousto-optic microwave - deflector with surface apodized piezoelectric transducer // Instruments and experimental techniques. - 2009, No. 1, p. 176-177] based on a piezoelectric crystal in the form of a parallelepiped, in which acoustic waves are generated using a piezoelectric transducer located on one of the lateral faces.

The principle of operation of the device is based on the well-known property of optical radiation - to diffract on a periodic structure arising from the elasto-optical effect when an ultrasonic wave propagates in a solid.

A common disadvantage of the known scanners is their large size (more than the radiation wavelength) and they are not intended for operation in the near zone of the forming device.

Known application of electrically controlled lens antennas based on ferroelectric materials [Patent US 4588994, Continuous ferrite aperture for electronic scanning antennas; Patent US 4480254, Electronic beam steering methods and apparatus; Patent US 4576441, Variable fresnel lens device; Patent US 5729239, Voltage controlled ferroelectric lens phased array; Patent US 6195059, Scanning lens antenna; Patent US 9591793, Deflecting device for electromagnetic radiation; Patent US 9490547, Electrical steering lens antenna]. Electrical control of the radiation pattern of ferroelectric quasi-optical antenna devices of the millimeter wavelength range is carried out by changing the refractive index of the ferroelectric in an electric field.

In the general case, an optical-type antenna consists of a primary radiation source and a quasi-optical device that converts the amplitude-phase spatial distribution of the primary radiator wave. As a primary emitter, a weakly directional antenna (for example, a dipole, an open end of a waveguide) is usually used, which carries out a wide-angle irradiation of a quasi-optical device (lenses, zone phase plates, etc.). The main property of a ferroelectric is the dependence of its dielectric constant on the strength of the applied electric field, which makes it possible to create designs for scanning lens antennas.

The disadvantages of the devices are the large dimensions of the forming element, the characteristic size of the lens aperture is tens and hundreds of wavelengths of the radiation used, electrically controlled lens antennas based on ferroelectric materials are designed to form the directional pattern and control it in space in the far zone.

As a prototype, a device for the formation of a photonic jet is adopted, consisting of a radiation source and a dielectric particle with a characteristic size comparable to the wavelength of the incident radiation, while the particle is made in the form of a particle with a flat lateral surface and equal thickness, and directly on the lateral surface of the particle, perpendicular to the incident radiation, a metal screen is installed at a distance from the illuminated end of the particle, ranging from 0 to L, where L is the length of the particle along the direction of incidence of radiation on it. [Minin I. V., Minin O. V. Device for the formation of a photon jet // RF Patent 191638, Published: 18.04.2019 Bulletin No. 23.]

The advantage of the device is expressed in the possibility of changing the spatial position of the formed photonic jet (its length) without changing the relative refractive index of the material of the dielectric particle.

The disadvantage of the device is the impossibility of changing the position of the photon jet transverse to the optical axis.

The objective of this useful model is to eliminate the indicated disadvantages, namely, to obtain the ability to control the transverse position in space of the formed photonic jet.

This task is achieved by the fact that the "photon jet" scanner in the microwave and EHF ranges consists of a radiation source and a dielectric particle with a characteristic size comparable to the wavelength of the incident radiation and made in the form of a particle with a flat lateral surface and equal thickness, and directly on the lateral surface of the particle, perpendicular to the incident radiation, a metal screen is installed, at a distance from the illuminated end face of the particle, which is in the range from 0 to L, where L is the length of the particle along the direction of incidence of radiation on it, according to the utility model, the screen is installed asymmetrically relative to the optical axis on one from the sides of the particle. In addition, the particle is shaped like a cube. In addition, the particle is in the form of a cylinder.

The claimed device for the formation of a photonic jet has a set of essential features unknown from the prior art for products of a similar purpose and unknown from available sources of scientific, technical and patent information on the date of filing an application for a utility model.

The utility model is illustrated by drawings.

FIG. 1 shows a "photon jet" scanner in the microwave and EHF ranges with a cube-shaped particle.

FIG. 2 shows a "photonic jet" scanner in the microwave and EHF ranges with a particle in the form of a cylinder.

FIG. 3 shows the results of modeling the control of the spatial position of the photonic jet depending on the position of the thin and wide screens on the lateral surface of the dielectric particle without changing the contrast of the refractive index.

Designations: 1 - radiation incident on a particle from a radiation source, 2 - a dielectric weakly absorbing particle in the form of a cube, 3 - a metal screen, 4 - a photon jet, 5 - a dielectric weakly absorbing particle in the form of a cylinder.

As a result of modeling the incidence of a plane wave on a dielectric cube and a cylinder with a screen installed asymmetrically relative to the optical axis on one of the lateral sides of the particle, it was shown that the position of the screen affects the spatial arrangement of the photonic jet, the displacement of the photonic jet from the optical axis of the device.

Experimental studies were carried out in the microwave range at a frequency of 20 GHz.

The dimensions of the dielectric cube-shaped particle were equal to the radiation wavelength λ, the refractive index of the particle material was 1.45-1.46, the thickness of the metal screen varied from 0.1λ to 0.5λ.

As a result of research, it was found that the strongest effect of the screen is observed in cases when the screen is located near the base of the cube, closest to the incident wave. As the screen moves towards the far base of the dielectric object, the effect of the screen weakens and it is minimal when the screen is located in the plane of the far base of the cube. Similar dependences were found for a cylindrical particle. The formed photonic jet is deflected from the optical axis towards the location of the screen on the lateral side of the dielectric particle.

When the screen is located directly on the lateral surface of the dielectric particle asymmetrically relative to the optical axis of the device, the spatial position of the generated photon jet depends on the position of the screen on its lateral surface. When the screen is located at the boundary of the illuminated end face of the particle (L = 0), depending on the value of the index of the particle material, the photonic jet turns towards the location of the screen. When the screen is located at a distance L, the parameters of the photonic jet practically do not change and it propagates along the optical axis.

The width of the metal shield is chosen not less than the thickness of the skin layer in the material of the metal shield at the frequency of the radiation source. With a smaller thickness, the metal screen becomes transparent to the incident radiation and the interference of waves from the diffraction of radiation on the metal screen and waves propagating through the dielectric particle becomes insufficient to change the spatial position of the formed photonic jet.

The screen can be made of an optically controlled material, for example, a semiconductor, for example, silicon, germanium. It is known that when a semiconductor material is irradiated with optical radiation, it passes into a conducting state and becomes opaque for terahertz and microwave radiation [Reed GT, Mashanovich G, Gardes FY, Thomson DJ. Silicon optical modulators. Nat Photon. 2010; 4: 518-26; Liu J, Beals M, Pomerene A, Bernardis S, Sun R, Cheng J, et al. Waveguide-integrated, ultralow-energy GeSi electro-absorption modulators. Nat Photon. 2008; 2: 433-7.]. In the manufacture of an optically controlled screen from a monolayer of graphene and its irradiation with optical radiation in the range, for example, 1550 nm [Bergen, MH, Born, B., Geoffroy-Gagnon, S., and Holzman, JF, "Terahertz microjets and graphene: Technologies toward ultrafast all-optical modulation, "Proc. IEEE Photonics Society Summer Topical Meeting Series (SUM), 10-12 July 2017, San Juan, Puerto Rico, paper 17103908 (2017); Wen, Q., Tian, W., Mao, Q., Chen, Z., Liu, W., Yang, Q., Sanderson, M. and Zhang, H. “Graphene based all-optical spatial terahertz modulator,” Sci. Reports, 4, 1-5 (2014)], it goes into a state that does not transmit terahertz and microwave radiation.

The device operates as follows. Electromagnetic radiation 1 incident on a weakly absorbing dielectric particle 2 or 5, as a result of wave interference on the particle and the screen 3 located directly on the lateral surface of the dielectric particle 2 or 5, forms a photon jet 4. When the position of the screen 3 changes along the lateral surface of the dielectric particle 2 or 5 the conditions of wave interference are changed and the spatial position of the photonic jet 4 changes.

The technical result achieved in this design of the "photonic jet" scanner in the microwave and EHF ranges is expressed in the possibility of changing the spatial position of the formed photonic jet, displacing it in the transverse direction relative to the optical axis of the device, without changing the relative refractive index of the material of the dielectric particle.

Claims (3)

1. Scanner "photon jet" in the microwave and EHF ranges, consisting of a radiation source and a dielectric particle with a characteristic size comparable to the wavelength of the incident radiation, and made in the form of a particle with a flat lateral surface and equal thickness, and directly on the lateral surface of the particle , perpendicular to the incident radiation, a metal screen is installed, at a distance from the illuminated end of the particle, which is in the range from 0 to L, where L is the particle length along the direction of incidence of radiation on it, characterized in that the screen is installed asymmetrically relative to the optical axis on one of the side sides of the particle. 2. The "photonic jet" scanner in the microwave and EHF ranges according to claim 1, characterized in that the particle is made in the form of a cube. 3. The "photonic jet" scanner in the microwave and EHF ranges according to claim 1, characterized in that the particle is made in the form of a cylinder.

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