CN106773101A

CN106773101A - It is a kind of to excite BSW to realize the optical chip of Beams coupling based on grating

Info

Publication number: CN106773101A
Application number: CN201710178129.5A
Authority: CN
Inventors: 王茹雪; 张斗国; 朱良富; 邱冬; 向益峰; 王沛; 明海
Original assignee: University of Science and Technology of China USTC
Current assignee: University of Science and Technology of China USTC
Priority date: 2017-03-23
Filing date: 2017-03-23
Publication date: 2017-05-31
Anticipated expiration: 2037-03-23
Also published as: CN106773101B

Abstract

The invention discloses it is a kind of based on grating to coupling excite BSW to realize the optical chip of Beams, including glass substrate layers, by low refractive index dielectric alternate group high into Bragg reflection unit, and Bragg reflection cell surface etching grating pair；The grating pair of Bragg reflection cell surface is placed in, two beam surface waves are interfered after exciting, so as to realize the generation of salt free ligands Bloch surface wave (BSW) light beam.The optical chip has the characteristics of compact conformation, high integration, miniaturization, and in beam shaping, nanocomposite optical operating aspect has important application.

Description

It is a kind of to excite BSW to realize the optical chip of Beams coupling based on grating

Technical field

The present invention relates to the technical field of the generation of the diffraction light-free of all dielectric, and in particular to one kind is based on grating to coupling BSW is excited to realize the optical chip of Beams.

Background technology

Bloch wave (BSW) is present in photonic crystal defect layer and the surface of surrounding dielectric layers, can be regarded as low damage Consumption and the analog of locality surface plasma (SPP) high.Similar with SPP, BSW is applied to nanoscale light path, chemistry and Bio-sensing, gas sensing, fluorescent radiation enhancing and SERS (SERS) etc..BSWs and SPP has following difference： (1) BSWs does not have the absorption loss of metal, therefore Bloch wave has the spread length of quality factor high and length；(2) can make Making the dielectric material of photonic crystal has multiple choices, therefore can produce deep ultraviolet to the BSWs of near infrared band, but SPPs It is very high in the loss of ultraviolet band and visible waveband；(3) severity that fluorescence is quenched in metal surface, but in medium Would not there is this in surface.

SPPs and BSWs when interface is propagated with the presence of Diffraction Problems, this cause light transmission when due to ripple bag It is extending transversely caused by coupling loss between chip element.In the past few years, with the development of plasma technique, Researcher proposes many methods planted and produce non-diffracted light, for example, periodic is carved on metal film, is adjusted with spatial light Device processed produces plasma Airy light；Being inscribed on metal film has grating pair, can so produce cosine Gauss plasma light Beam；Plasma Airy light can be become line style light by the metal medium metal structure using wedge shape.The optical core of these structures Piece all has certain limitation, and its problem being primarily present is：(1) it is lost big.The imaginary part of dielectric constant of metal is very big, profit The optical chip of Beams is realized with metal structure, its loss is very big, reduces the conveying length of Beams.(2) Poor practicability.Diffraction light-free from curvature effect and short transmission range the features such as all greatly reduce it in practical process Using effect.

The content of the invention

The purpose of the present invention overcomes the absorption loss of metal, using the coupling of dielectric grating pair and Bragg reflection unit, The diffraction light-free of all dielectric is realized, is a simple structure, the optical chip of low processing cost.

The present invention realizes that the technical scheme of above-mentioned purpose is as follows：

A kind of to excite BSW to realize the optical chip of Beams coupling based on grating, the optical chip includes glass Substrate, Bragg reflection unit, grating pair and deionized water；Wherein, described Bragg reflection unit, deionized water are arranged successively Put on the glass substrate；The grating is opposite in Bragg reflection unit top layer；Described Bragg reflection unit and grating Pair can produce BSW light beams, grating that two produced beam BSW are interfered with generation salt free ligands BSW light beams and deionized water between.

Wherein, described Bragg reflection unit is by high refractive index medium Si₃N₄Layer and low refractive index dielectric SiO₂Layer is alternately Composition, top layer is SiO₂Defect layer, altogether 14 layers.

Wherein, alternate Si3N4, SiO2 and defect layer thickness are adjustable in described Bragg reflection unit, to control The reflectivity curve of Bragg reflection unit processed, regulation BSW couples the position of outgoing formant.

Wherein, described grating is 460nm to the cycle, and line width is 200nm, and depth is 100nm, and length is 30 μm, cycle Number is 20, and grating is 170 degree to angle, can change diffraction light-free by changing the length and angle of grating pair The length of beam, coupling efficiency is changed by changing the depth and line width of grating pair.

The principle of technical solution of the present invention is：It is a kind of to excite BSW to realize the optics of Beams coupling based on grating Chip, the optical chip includes substrate of glass, Bragg reflection unit, is engraved in the grating pair of Bragg reflection unit top layer and goes Ionized water；Wherein, described Bragg reflection unit and grating pair and deionized water can be produced two beams after laser excitation BSW, two beam BSW interference produce salt free ligands light wave；Using focused-ion-beam lithography method inscribe in Bragg reflection unit Two groups of grating angles of top layer are variable, and variable period, line width is variable, and variable depth, position is variable, and single seam length is variable；Grating To cycle it is Wavelength matched with the BSW of Bragg reflection unit, can reach maximum coupling efficiency；The depth of grating pair and Line width changes, and can improve the coupling efficiency of BSW；Aperture barrier is inscribed on salt free ligands BSW paths, salt free ligands BSW can be produced It is conigenous reparation phenomenon；Change the size of aperture, thus it is possible to vary selfreparing distance.

BSW, laser can be produced to beat and excited to can above couple in grating in the Bragg reflection unit of multilayer dielectric film composition BSW, two gratings have certain angle, therefore two beam Bloch waves can be overlapped, and the part of overlap interferes, and form salt free ligands Light wave.

The present invention is the characteristics of compared with conventional art：

(1) surface texture is simple：Only need to Bragg reflection unit top layer inscribe have certain angle two groups of gratings and The aperture of ad-hoc location；

(2) it is easy to process：For the position of grating pair, without strict requirements, this is very big for seam length, depth, line width etc. The difficulty of processing is reduced in degree；

(3) it is practical：Place barrier on the path of diffraction light wave transmissions, the selfreparing quickly of diffraction light-free wave energy, Increased the practicality of Beams.

Brief description of the drawings

Fig. 1 is that the present invention is a kind of excites BSW to realize the knot of the optical chip of Beams generation based on grating to coupling Structure schematic perspective view；

Fig. 2 is that the present invention is a kind of excites BSW to realize the knot of the optical chip of Beams generation based on grating to coupling Structure tangent plane schematic diagram；

Fig. 3 is that the salt free ligands cosine Gauss Bloch wave light beam obtained using the chip tests front focal plane picture, back focal plane picture, Theoretical front focal plane picture, theoretical and experiment intensity profile figure, single grating excitating surface Bloch wave front focal plane picture, wherein, Fig. 3 A () is the image planes figure of salt free ligands BSW generations, Fig. 3 (b) and Fig. 3 (d) is respectively experiment and the theoretical Beams for obtaining are transversal The fitting schematic diagram in face, Fig. 3 (c) is the result schematic diagram simulated with FDTD, and Fig. 3 (e) is that the situation that single grating is excited is illustrated Figure, Fig. 3 (f) is to be respectively Fig. 3 (a) and the corresponding back focal plane figures of Fig. 3 (e) with Fig. 3 (g).

Reference implication is：1 is substrate of glass, and 2 is Bragg reflection unit, and 3 is grating pair, and 4 is deionized water, 5 It it is Si3N4 layers, 6 is SiO2 layers, and 7 is SiO₂Defect layer.

Specific embodiment

The present invention is further described in detail with reference to the accompanying drawings and detailed description.

Embodiment 1：

Shown in reference picture 1-2 it is a kind of based on grating to coupling excite BSW to realize the optical chip of Beams, including Substrate of glass 1, Bragg reflection unit 2, grating is to 3, deionized water 4.Wherein Bragg reflection unit is by 66nm Si₃N₄Layer 5 With the SiO of 110nm₂Layer 6 is alternately constituted, the SiO of top layer₂The thickness of defect layer 7 is 450nm.The cycle of grating pair is carved with for 460nm, Angle is 170 °, and depth is 100nm, and line width is 200nm.The wave vector 460nm of Bragg reflection cell surface BSW, with grating pair Cycle match.633nm exciting lights are incident from optical chip top, with Bragg reflection unit and grating to coupling generation Salt free ligands BSW, salt free ligands BSW is got off from exciting light with different angle radiations, and BSW angles are 64 degree, and we can be by Fig. 3 F () and Fig. 3 (g) back focal planes figure release angle of radiation.Fig. 3 (a) is the image planes figure of salt free ligands BSW generations, and Fig. 3 (c) is to use FDTD The result of the Beams of simulation, Fig. 3 (e) is the situation that single grating is excited.Fig. 3 (b) and Fig. 3 (d) be respectively experiment and The Beams cross section of notional result fitting it can be seen that different propagation positions at halfwidth it is constant, and experiment and Theoretical halfwidth is consistent, and cross-section curve fitted figure can intuitively find out the non-diffraction beam of salt free ligands BSW light very much.

What the present invention was not elaborated partly belongs to techniques well known.

Claims

It is 1. a kind of to excite BSW to realize the optical chip of Beams coupling based on grating, it is characterised in that：The optical chip Including substrate of glass (1), Bragg reflection unit (2), grating to (3) and deionized water (4)；Wherein, described Prague is anti- Unit (2), deionized water (4) is penetrated to be emitted on successively in substrate of glass (1)；The grating is placed in Bragg reflection unit to (3) (2) in top layer；Described Bragg reflection unit (2) and grating between (3) and deionized water (4) to that can produce BSW light beams, light Grid interfere generation salt free ligands BSW light beams to two beam BSW produced by (3).
2. it is according to claim 1 it is a kind of based on grating to coupling excite BSW to realize the optical chip of Beams, its It is characterised by：Described Bragg reflection unit (2) is by high refractive index medium Si₃N₄Layer (5) and low refractive index dielectric SiO₂Layer (6) alternately constitute, top layer is SiO₂Defect layer (7), altogether 14 layers.
3. it is according to claim 1 it is a kind of based on grating to coupling excite BSW to realize the optical chip of Beams, its It is characterised by：Alternate Si3N4, SiO2 and defect layer thickness are adjustable in described Bragg reflection unit (2), to control The reflectivity curve of Bragg reflection unit, regulation BSW couples the position of outgoing formant.
4. it is according to claim 1 it is a kind of based on grating to coupling excite BSW to realize the optical chip of Beams, its It is characterised by：Described grating is 460nm to (3) cycle, and line width is 200nm, and depth is 100nm, and length is 30 μm, the cycle Number is 20, and grating is 170 degree to angle, can change Beams by changing the length and angle of grating pair Length, change coupling efficiency by changing the depth and line width of grating pair.