CN101825744B - High-nonlinearity composite-structure micro-nano optical wave conducting wire and preparation method thereof - Google Patents

Abstract

The invention discloses a micro-nano optical waveguide with a highly nonlinear composite structure, which is characterized in that it includes a silica micro-optical fiber, the length of which is equal to or greater than 30 millimeters, and the diameter is 0.4 to 8 microns, and the surface is deposited with 1 by LB coating technology. ~100 layers of halophilic bacteria purple film, each layer of halophilic bacteria purple film thickness is 5-20 nanometers; both ends of the silica micro-optical fiber are connected to standard optical fibers through a tapered transition zone, and are used to connect various optical instruments. The highly nonlinear composite structure micro-nano optical waveguide is a combination of silica micro-nano optical waveguide with sub-wavelength diameter and halophilic bacteria purple film material coating, which has a large proportion of evanescent wave transmission and extremely high optical non-conductivity. linear characteristics.

Description

A highly nonlinear composite structure micro-nano optical waveguide and its preparation method

technical field

The invention relates to the technical fields of LB coating and micro-nano optics, in particular to a composite structure sub-wavelength diameter micro-nano optical waveguide based on LB coating.

Background technique

Langmuir-Blogeet membrane, referred to as LB membrane, is to disperse amphiphilic molecules with hydrophilic head and hydrophobic tail on the water surface (subphase), and apply pressure to the water surface in the horizontal direction, so that the molecules are closely arranged on the water surface to form a An insoluble monomolecular film with ordered layers. LB film technology is a technology that transfers the above-mentioned monomolecular film on the gas/liquid interface to the solid surface and realizes continuous transfer assembly. LB film has the characteristics of accurate control of film thickness, no high conditions for film formation, simple and easy operation, and highly orderly arrangement of molecules in the film. Therefore, assembly at the molecular level can be realized. Fields such as chemistry and bionics have broad application prospects. In recent years, many studies have been carried out, involving the biomimetic simulation of biomembranes, the preparation of ultra-thin films, optics, and sensors. The purple membrane of halophilic bacteria is an excellent nonlinear optical (NLO) material. As a typical light-sensitive cell membrane, a protein—bacteriorhodopsin (BR) plays a nonlinear role. In function and structure, BR is very similar to the photoreceptor on the animal retina—rhodopsin molecule, which is very sensitive to light. When BR absorbs photons, it will drive protons to move across the membrane, and it will go through a series of intermediate states to return to the original state. Complete a light cycle, so it has a very important application prospect in optical information processing and optical computing technology. The sub-wavelength diameter micro-nano optical waveguide drawn from ordinary single-mode optical fiber by high-temperature stretching method can have a surface roughness as low as the atomic level, a very uniform diameter, and the optical transmission loss is much smaller than other types of sub-wavelength scale optical waveguides. It can exhibit the characteristics of strong optical field confinement, large-scale evanescent wave, and high nonlinearity, and has potential application value in micro-nano photonic devices, photon sensing, nonlinear optics, and atomic waveguides.

Because in the existing reports, the LB coating process is completed on a glass substrate, there are limitations in the size, shape and integration of the substrate with the optical system.

Contents of the invention

The problem to be solved by the present invention is: how to provide a Wiener optical waveguide with a highly nonlinear composite structure and its preparation method. There is great application potential in the research of various micro-nanophotonic devices and biophotonic devices.

The technical problem proposed by the present invention is solved as follows: provide a highly nonlinear composite structure micro-nano optical waveguide, which is characterized in that it includes a silica micro-optical fiber whose length is equal to or greater than 30 mm and whose diameter is 0.4 to 8 microns , the surface is deposited with 1 to 100 layers of halophilic purple film by LB coating technology, and the thickness of each layer of halophilic purple film is 5 to 20 nanometers; the two ends of the silica micro-optical fiber are connected to the standard optical fiber through a tapered transition zone , used to connect various optical instruments.

A method for preparing a micro-nano optical waveguide with a highly nonlinear composite structure, characterized in that it includes the following steps:

①Using silica microfibers with a diameter of 0.4-8 microns and a length equal to or greater than 30 mm as the substrate, placed in the subphase;

②Make the halophilic bacteria purple membrane molecules on the surface of the subphase form a tightly arranged monomolecular film, lift the silica microfiber from the subphase liquid surface along the vertical direction, and under the action of the membrane pressure, the air/liquid interface surface is continuously transferred To the surface of the silica micro-optical fiber, a layer of monomolecular halophilic bacteria purple film LB film is formed, and the speed of the silica micro-fiber is controlled so that the thickness of the halophilic bacteria purple film LB is 5 to 20 nanometers;

③Repeat step ②(N-1) times to obtain N layers of halophilic bacteria purple film, wherein 1≤N≤100;

④ Connect the silica micro-fiber obtained in step ③ to a standard optical fiber through a tapered transition zone for connecting various optical instruments.

Beneficial effects of the present invention: the present invention uses silica micro-optical fibers with a diameter of 1 micron as a substrate, and deposits a layer of halophilic purple film on the surface of the micro-nano optical waveguide through LB coating technology, with a thickness of 5 nanometers. Light is transmitted in the form of large-scale evanescent waves in the micro-nano optical waveguide, and the evanescent waves transmitted on its surface interact with the molecules of the purple membrane of halophilic bacteria, which can produce extremely high optical nonlinear effects. Compared with ordinary silica fiber and ordinary micro-fiber, this kind of highly nonlinear composite structured optical nanowire has higher optical nonlinear effect, and can be used in pulse compression, wavelength conversion, bio-optical switch, optical storage, photon sensing and various It has great application potential in the research of various micro-nano photonic devices and biophotonic devices.

The present invention proposes to combine LB coating technology with micro-nano optical waveguide with sub-wavelength diameter for the first time. The excellent optical nonlinear effect of halophilic bacteria purple film and the same excellent optical nonlinear characteristics of micro optical fiber are combined through LB coating method to obtain a A micro-nano optical waveguide with a highly nonlinear composite structure, the nonlinear optical characteristics of the waveguide will be greatly improved. This highly nonlinear composite structure micro-nano optical waveguide has great application potential in the research of pulse compression, wavelength conversion, bio-optical switch, optical storage, photon sensing, and various micro-nano photonic devices and micro-nano optoelectronic devices.

Description of drawings

Fig. 1 is a schematic structural diagram of a micro-nano optical waveguide with a highly nonlinear composite structure;

Figure 2 is a schematic diagram of the LB film forming principle of the highly nonlinear composite structure micro-nano optical waveguide;

Figure 3 is a schematic diagram of the micro-nano optical waveguide LB coating process

Fig. 4 is a schematic diagram of a coating device for a micro-nano optical waveguide with a highly nonlinear composite structure;

Fig. 5 is a schematic diagram of the optical nonlinear effect of the composite structure micro-nano optical waveguide;

Among them, 1. Standard optical fiber, 2. Purple film coating layer of halophilic bacteria, 3. Standard optical fiber, 4. Silica micro-optical fiber, 5. Tapered transition zone, 6. Monolayer of halophilic bacteria, 7. Grid , 8. Subphase, 9. Spectrometer or oscilloscope, 10. Micro-nano optical waveguide, 11. Coating machine wall, 12. Optical fiber fixture, 13. LB film monolayer and deionized water.

Detailed ways

The present invention will be further described below in conjunction with accompanying drawing:

As shown in Figure 1, the parameters of this highly nonlinear composite structure micro-nano optical waveguide are as follows: including silica micro-optical fiber 4 and halophilic bacteria purple film coating layer 2, the halophilic bacteria purple film monomolecular film is deposited on The surface of the micro-nano optical waveguide is coated 100 times, that is, 100 layers of halophilic bacteria purple monomolecular film are deposited on the surface of the micro-nano optical waveguide, with a thickness of 500 nanometers. The length of this section of the structure should not be less than 30 mm. Both ends of the micro-nano optical waveguide with a highly nonlinear composite structure are connected to standard optical fibers 1 and 3 through the tapered transition zone 5 of the silica micro-nano optical waveguide, and are used to connect with various optical instruments.

The preparation principle of the highly linear composite structure micro-nano optical waveguide is shown in Figure 2: under a certain pressure, the halophilic bacteria purple membrane molecules on the surface of the subphase form a tightly arranged monomolecular film 6, and the micro-nano optical waveguide 10 takes a certain pressure. The velocity is raised from the liquid surface in the vertical direction, and under the action of the membrane pressure, the surface of the gas/liquid interface is continuously transferred to the surface of the micro-nano optical waveguide, forming a layer of monomolecular halophilic bacteria purple membrane LB membrane.

As shown in Figure 3 and Figure 4, the preparation system structure includes: standard optical fiber 1, silica micro-fiber 4, tapered transition zone 5, halophilic bacteria purple membrane monomolecular layer 6, barrier (barrier) 7 for controlling membrane pressure , deionized water (subphase) 8, LB coating tank 9, micro-nano optical waveguide 10, coating machine arm (holder) 11, optical fiber clamp 12, LB film monolayer and deionized water (subphase) 13. The basic process of preparation is that the micro-optical fiber moves along the vertical direction at a certain speed. Since the membrane pressure of the purple membrane monolayer of halophilic bacteria is maintained constant, every time the micro-optical fiber passes through the liquid surface, it will flow from the gas/liquid surface Transfer a layer of purple film to the surface of the micro-nano optical waveguide. Set the software parameters and repeat 100 times to obtain this kind of highly nonlinear composite structure micro-nano optical waveguide.

The preparation parameters of the composite structure micro-nano optical waveguide are as follows: the sub-phase used in the coating process is secondary deionized water 8, the resistivity is 18.25 MΩ/cm, and the temperature is constant at 20 degrees Celsius. The prepared 0.5 mg/ml purple membrane dimethylformamide solution was dropped dropwise on the surface of the subphase, and diffused for one hour to form a purple membrane monolayer 6 of halophilic bacteria. Silica micro-nano optical waveguide 1 is a micro-nano optical waveguide with a diameter of 1.3 microns and high diameter uniformity and surface roughness, which is heated and softened by an alcohol lamp to soften an ordinary single-mode optical fiber, and then slowly drawn. Place the drawn micro-nano optical waveguide on the fiber holder 12 of the LB coating system. Set the film pressure to be constant at 40mN, the pulling speed to be 5mm/min, and the number of coating times to be 100.

Example 1

A micro-nano optical waveguide with a diameter of 1 micron and good surface uniformity is produced by a one-step high-temperature drawing method. The micro-nano optical waveguide is connected to the standard single-mode optical fiber through the tapered transition zone of the optical fiber, and the optical fiber is placed on the optical fiber fixture of the LB coating machine. Spread the 0.05mg/ml purple film dimethylformamide solution on the surface of the subphase (secondary deionized water), and after volatilizing for 1 hour, control the temperature of the subphase to stabilize at 20°C, and then start the coating. The basic process of preparation is that the micro-optical fiber moves along the vertical direction at a certain speed. Since the membrane pressure of the purple membrane monolayer of halophilic bacteria is maintained constant, every time the micro-nano optical waveguide passes through the liquid surface, it will flow from the gas/ The liquid surface transfers a layer of purple film to the surface of the micro-nano optical waveguide. Set the software parameters and repeat 100 times to obtain this kind of highly nonlinear composite structure micro-nano optical waveguide. Figure 5 is a schematic diagram of the optical nonlinear effect of the composite structure micro-nano optical waveguide

The above specific implementation methods are used to explain the device of the present invention, rather than to limit the present invention. Within the spirit of the present invention and the protection scope of the rights specification, any changes and variations of the present invention fall within the protection scope of the present invention.

Claims (2)

1. A micro-nano optical waveguide with a highly nonlinear composite structure, characterized in that it includes a silica micro-optical fiber whose length is equal to or greater than 30 millimeters and whose diameter is 0.4 to 8 microns, and the surface is deposited with 1 to 100 microns by LB coating technology. The thickness of each layer of halophilic bacteria purple film is 5-20 nanometers; the two ends of the silica micro-optical fiber are connected to standard optical fibers through a tapered transition zone, and are used to connect various optical instruments. 2. A method for preparing a micro-nano optical waveguide with a highly nonlinear composite structure, comprising the following steps: ①Using silica microfibers with a diameter of 0.4-8 microns and a length equal to or greater than 30 mm as the substrate, placed in the subphase; ②Make the halophilic bacteria purple membrane molecules on the surface of the subphase form a tightly arranged monomolecular film, lift the silica microfiber from the subphase liquid surface along the vertical direction, and under the action of the membrane pressure, the air/liquid interface surface is continuously transferred To the surface of the silica micro-optical fiber, a layer of monomolecular halophilic bacteria purple film LB film is formed, and the speed of the silica micro-fiber is controlled so that the thickness of the halophilic bacteria purple film LB film is 5 to 20 nanometers; ③Repeat step ②(N-1) times to obtain N layers of halophilic bacteria purple film LB film, wherein 1≤N≤100; ④ Connect the silica micro-fiber obtained in step ③ to a standard optical fiber through a tapered transition zone for connecting various optical instruments.

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