Equivalent resonant cavity structure enhanced superlens constructed based on laser substance

Abstract

The invention belongs to an equivalent resonant cavity structure enhanced super lens constructed by a laser material. The equivalent resonant cavity structure enhanced super lens comprises a substrate, a metal film layer, a laser material layer and a super lens structure layer. An equivalent resonant cavity structure similar to a laser structure is constructed by the metal film layer, the laser material layer and the super-lens structure layer. By utilizing the cavity structure and laser substance enhancement, the light transmission energy of the super lens is enhanced. The working efficiency of the super lens is effectively improved, and the far-field light transmission capability is enhanced. And the requirements of miniaturization and integration of a super-lens photoelectric device can be met.

Description

Technical Field

[0001] The invention belongs to the field of micro-nano optics and optical nanomaterials, and in particular relates to an equivalent resonant cavity structure-enhanced superlens constructed based on laser material. Background Art

[0002] 1. Superlens, also known as superstructure lens, uses one-dimensional, two-dimensional, three-dimensional and other sub-wavelength structures to achieve precise modulation of electromagnetic waves, including deflection, polarization, focusing, holographic imaging, etc. It uses sub-wavelength superstructures to couple electromagnetic waves to generate surface plasmon polaritons (SPPs). By controlling SPPs, the wavefront shape of the incident light can be adjusted, thereby achieving all-round control of the light field in a very thin plane area. Compared with the traditional lens method of achieving beam shaping by producing continuous light refraction through curved surfaces. Superlenses have good performance advantages in modulation accuracy, modulation diversity, device miniaturization, integration, and achromatism.

[0003] 2. The electromagnetic wave modulation of the superlens is based on the enhancement of the local field of surface plasma. SPPs are generally bound to the medium and metal surface and cannot achieve high-efficiency transmission in the far field. In Xue Jing's master's thesis "Research on the Transmission Phenomenon of Subwavelength Metal Hole Array Surface Plasmon Enhancement", Fudan University, it was experimentally proved that the horizontal surface plasma resonance mechanism generated at the metal / air and metal / glass interfaces played a major role in the enhanced transmission phenomenon. The mechanism of each resonance peak and its corresponding relationship with the crystal structure constant were theoretically explained. Due to the coupling of the surface plasma wave vector and the reciprocal lattice vector, the transmission of certain incident wavelengths was enhanced. However, it only confirmed that SPPs have a positive effect on the enhanced transmission of superlens electromagnetic waves, and this effect is limited to near-field enhancement.

[0004] 3. The patent document with announcement number CN 102957086A discloses "A deep subwavelength surface plasma laser". The laser uses a surface plasma laser composed of a nanowire / air / metal film / substrate structure. The invention uses air gaps to generate lasers, improves the electric field enhancement effect and compatibility with various optical waveguides and devices. It provides a new technical approach for micro-nano lasers in micro-nano photonics. Although this laser can produce efficient laser enhancement and transmission, it does not have the precise control of electromagnetic waves like a super lens.

[0005] 4. The patent document with announcement number CN201510823645.X discloses "A beam-controllable nanowire laser based on graphic growth". This invention belongs to a beam-controllable nanowire laser based on graphic growth. The beam-controllable nanowire laser includes a substrate, an isolation medium, a graphic groove opened in the isolation medium, and a nanowire array grown in the groove. The invention combines the luminous properties of nanowires with the design of superlens to produce a graphic area for beam control for nanowire growth, so that the output light of the nanowire can be collimated, focused and other beam controls. This overcomes the shortcomings of severe scattering of nanowire light and low energy utilization. It improves the practical application of nanowire lasers in miniaturized and integrated optical devices. However, the preparation process of this graphic nanowire array structure based on superlens design is complicated, and the preparation accuracy is difficult to meet the requirements of superlens with complex structures.

[0006] 5. In the doctoral thesis "Design and Research of V-Shaped Antenna Based on Surface Plasmon" by Jiao Jiao of the University of Electronic Science and Technology of China, he designed a MIM surface plasma local enhanced superlens structure of metal / medium / superlens metal layer. The design simulation structure shows that this structure can produce a localized surface plasma resonant cavity, thereby increasing the light transmission efficiency of the superlens. However, the medium used in this structure is not a laser material with laser enhancement function, so the light enhancement it produces is also limited to the near field area. Summary of the invention

[0007] The present invention is aimed at the defects of the background technology, and designs an equivalent resonant cavity structure enhanced superlens based on laser material, so as to utilize the filled laser material, and form an enhanced resonant cavity similar to the laser structure with the superlens structure layer and the metal film layer, and the filled laser material is the working material. Therefore, this design can enhance the light transmission conversion efficiency of the superlens and break through the near-field transmission limitation. The structure is simple, easy to process, and meets the purpose of miniaturization and integration.

[0008] The solution of the present invention is to propose to use a metal film layer / laser material layer / super lens structure layer to jointly construct an equivalent resonant cavity structure similar to the laser structure based on the background technology. It uses this cavity structure and laser material enhancement to enhance the light transmission energy of the super lens. Therefore, the present invention is an equivalent resonant cavity structure enhanced super lens based on laser material, including a substrate, a metal film, a laser material, and a super lens structure; the key is that the equivalent resonant cavity structure formed by this structure can give the super lens sufficient energy enhancement.

[0009] The above-mentioned super lens structure is a V-shaped nanostructure, and its material is Au; the laser material is the laser material gallium (Ga), arsenic (As), indium (In), phosphorus (P), Ga·Al·As and other materials used in semiconductor lasers; and the laser materials corundum (NaAlSi2O6), yttrium aluminum garnet (Y3Al5, O12), calcium tungstate (CaWO4), calcium fluoride (CaF2) and yttrium aluminate (YAlO3), lanthanum beryllium oxide (La2Be2O5), barium crown glass, calcium crown glass, ruby ​​(Al2O3:Cr3+) and neodymium-doped yttrium aluminum garnet (abbreviated as YAG:Nd3+), neodymium glass. And other laser materials that can achieve laser power enhancement. The thickness range is preferably 50-200nm. The substrate is a 200nm thick Si substrate with a layer of Au film magnetron sputtered, and the film thickness ranges from 5 to 20nm; the periodic size of the V-shaped nanoantenna is determined according to the wavelength, which is less than 1 and greater than 1 / 10. According to different device processes, "positive pattern" or "negative pattern" is generally used for preparation.

[0010] Superlenses generally have problems such as local enhancement in the near field, severe attenuation in the far field, and low light energy utilization. An equivalent resonant cavity structure-enhanced superlens based on laser material is proposed to achieve light field energy compensation and enhancement. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 An enhanced superlens (cross-sectional view) based on an equivalent resonant cavity structure constructed based on laser matter;

[0012] Figure 2 for Figure 1 A top view of

[0013] Figure 3 A top view of the V-shaped nanowire antenna array superlens structure used in Example 1;

[0014] Figure 4 The electric field distribution diagram of the y-plane and the z-plane in the simulation experiment of the first embodiment, and the light intensity distribution curve of the x-cross section at the center of the focus spot in the simulation experiment.

[0015] In the figure: 1. Super lens structure layer, 2. Laser material layer, 3. Metal film layer, 4. Substrate, 5. Equivalent resonant cavity DETAILED DESCRIPTION

[0016] (1) The superlens structure is a V-shaped nanostructure, and its material is Au;

[0017] (2) The laser material is Ga·Al·As with a thickness of 50nm;

[0018] (3) magnetron sputtering a layer of Au film on a 200 nm thick Si substrate, with a film thickness range of 10 nm;

[0019] (4) The designed V-shaped nanoantenna is composed of two antenna rods connected at one end and rotated at an angle α. When using the V-shaped nanoantenna to design a superlens, the antenna arm length l, antenna arm width w, antenna thickness h, antenna angle α, and azimuth angle β between the antenna symmetry axis and the x-axis are mainly optimized.

[0020] (5) Polar coordinates are used to calculate the coordinate position of each antenna. Let r be the horizontal coordinate and θ be the angular coordinate, so the Cartesian coordinate equation can be obtained:

[0021]

[0022] The difference between the rings is set as Δr, and i is set as the i-th ring, so the radius of the ring is r = i·Δr. In this way, a superlens composed of a V-shaped nanoantenna array is obtained;

[0023] (6) The diameter of the metalens is 8 mm, which is determined by the incident wavelength;

[0024] (7) Using photolithography technology to prepare a superlens structure;

[0025] (8) The superlens is a "negative shape", that is, a hollow form.

[0026] This method has the advantages of simple structure, easy integration, high field enhancement effect, etc., which can effectively improve the working efficiency of the superlens. It can also meet the requirements of miniaturization and integration of superlens optoelectronic devices.

Claims

1. An equivalent resonant cavity structure-enhanced superlens based on laser material, comprising a substrate, a metal film layer, a laser material and a superlens. It is characterized by A thin metal layer is plated on the substrate, and then laser material is added on the metal film layer. A layer of medium required for preparing the superlens is plated on the laser material. The medium layer is photolithographically processed to prepare the superlens structure, thereby forming an equivalent resonant cavity structure of metal layer-laser material-superlens structure layer.

2. The equivalent resonant cavity structure-enhanced superlens constructed based on laser material according to claim 1, characterized in that The laser materials used are gallium (Ga), arsenic (As), indium (In), phosphorus (P), Ga·Al·As and other materials used in semiconductor lasers; As well as the laser materials used in solid-state lasers, such as corundum (NaAlSi2O6), yttrium aluminum garnet (Y3Al5, O12), calcium tungstate (CaWO4), calcium fluoride (CaF2), yttrium aluminate (YAlO3), lanthanum beryllium oxide (La2Be2O5), barium crown glass, calcium crown glass, ruby ​​(Al2O3:Cr3+), neodymium-doped yttrium aluminum garnet (abbreviated as YAG:Nd3+), and neodymium glass. And other laser materials that can achieve laser power enhancement.

3. The equivalent resonant cavity structure-enhanced superlens constructed based on laser material according to claim 1, characterized in that The superlens morphology can be a Fresnel zone plate, a micro-nano groove, a V-shaped structure, a grating structure, a catenary structure, other micro-nano planar lens structures and other beam control structures.

4. The equivalent resonant cavity structure-enhanced superlens constructed based on laser material according to claim 1, characterized in that The material of the metal film layer is any one of metal materials such as gold, silver, aluminum, copper, nickel, chromium, etc.

5. The equivalent resonant cavity structure-enhanced superlens constructed based on laser material according to claim 1, characterized in that The substrate materials are silicon, sapphire, gallium nitride, optical glass, silicon dioxide, etc.

6. The equivalent resonant cavity structure-enhanced superlens constructed based on laser material according to claim 1, characterized in that The superstructure material is any one of metal materials such as gold, silver, aluminum, copper, etc., and any one of non-metal materials such as silicon dioxide, silicon, gallium nitride, etc.

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