Preparation method of insensitive silicon dioxide optical glass of high-energy laser system

Abstract

The invention relates to the technical field of optical glass of a high-energy laser system, in particular to a preparation method of insensitive silicon dioxide optical glass of the high-energy laser system, the glass contains a mesostructure and is formed by curing nano silicon dioxide particles, the silicon dioxide particles are all integrated on the optical layer, and the optical glass is formed by curing the nano silicon dioxide particles. The mechanical layer is of a porous network and compact area composite structure; a mesostructure endows the silicon dioxide glass with the insensitive characteristic, namely, the silicon dioxide glass has the advantages of high laser damage growth threshold, slow laser damage growth, insensitivity to the environment, high laser load and long service life in a high-energy laser system. The purity of the insensitive silica glass is improved, the mesostructure of the insensitive silica glass with long service life and high damage value-added threshold is optimized, meanwhile, the novel insensitive optical glass is created by taking silica as a base material and fusing a preparation method, and the processing quality is improved.

Description

Technical Field

[0001] The invention relates to the technical field of optical glass for high energy laser systems, in particular to a method for preparing insensitive silicon dioxide optical glass for high energy laser systems. Background Art

[0002] As one of the core components of high-energy laser systems, optical glass can play an important role in the military, medical and scientific research fields. Silica optical glass is one of the optical materials. Silica glass is a special glass composed of silicon dioxide molecules with excellent thermal stability, mechanical properties and chemical stability. This material has a high refractive index and transmittance and can be used to make high-precision optical devices and optical instruments.

[0003] Among them, inertial confinement fusion has important strategic significance for ensuring human energy security and sustainable development. The key platform of laser inertial confinement fusion is high-energy laser. In the development process of high-energy laser, laser-induced damage of a large number of ultraviolet optical components inside the laser is a prominent problem that needs to be solved urgently.

[0004] In the existing technology, optical glass often has a short component life due to its low laser damage threshold and fast growth rate after damage. The silica glass prepared by the traditional melting method requires high-temperature treatment and is difficult to control the mesostructure, resulting in the preparation of optical glass unable to meet the demand, thus affecting the processing quality of optical glass. Summary of the invention

[0005] The object of the present invention is to provide a method for preparing insensitive silica optical glass for high energy laser system to solve the problems raised in the above background technology.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A method for preparing insensitive silica optical glass for a high-energy laser system. The glass contains a mesoscopic structure formed by solidifying nano-silicon dioxide particles. The silica particles are uniform at the optical level and a composite structure of porous networks and dense regions at the mechanical level.

[0008] Preferably, the preparation method comprises the following steps:

[0009] S1, using metal alkoxide and phosphoric acid as reaction precursors, hydrolyzing and polymerizing in the presence of silicate, catalyst and water, to synthesize silica spherical particle sol by a liquid phase method;

[0010] S2, adjusting parameters such as reactant concentration, reaction temperature and reaction rate to control the size of the spherical silica particles within the range of 50-200 nm;

[0011] S3. After the sol is gelled, use the supercritical drying technology for solidification and forming;

[0012] S4. Heat-treat the solidified gel. By controlling the heat-treatment temperature of 300 - 1000 °C, the heat-treatment time of 1 - 36 h, and the heat-treatment process, including stepwise heating or constant temperature, obtain insensitive silica optical glasses with different sintering degrees;

[0013] S5. Place the insensitive silica optical glasses with different sintering degrees on a laser damage test platform, and then use a 351 nm ultraviolet laser to test the laser damage threshold and the laser damage growth threshold of the insensitive silica glass.

[0014] Preferably, the metal alkoxide includes methyl orthosilicate, and the addition amount of phosphoric acid is 0.1 - 0.6% of the total mass of the precursors.

[0015] Preferably, the medium for supercritical drying is liquid CO₂, the drying pressure is 7 - 12 MPa, and the temperature is 32 - 50 °C.

[0016] Preferably, the heat-treatment process includes:

[0017] The first stage: Heat up to 300 - 600 °C at a rate of 5 - 8 °C / min and hold for 2 - 12 h to remove organic residues;

[0018] The second stage: Heat up to 800 - 1000 °C at a rate of 1 - 3 °C / min and hold for 1 - 18 h to achieve densification.

[0019] Preferably, the laser irradiation conditions are: laser wavelength is 351 nm, pulse width is 8 ns, pulse frequency is 60 Hz, pulse energy is 18 mJ, and irradiation time is 10 min.

[0020] Preferably, the laser damage test includes: laser damage threshold ≥ 15 J / cm 2 ; damage growth threshold ≥ 8 J / cm 2 ; damage growth coefficient ≤ 1.

[0021] Preferably, the preparation method of the insensitive silica optical glass can obtain an insensitive silica optical glass. The mesoscopic structure of the insensitive silica optical glass is a composite structure of a porous network and a dense region, and the controllable range of the porosity is 5% - 10%.

[0022] Application of the optical glass produced by the preparation method of the insensitive silica optical glass for high-energy laser systems in high-energy laser systems.

[0023] Advantages of the present invention:

[0024] 1. The present invention adopts a preparation method for synthesizing insensitive silica optical glass for high-energy laser systems by the liquid-phase method, which improves the purity of the insensitive silica glass and optimizes the mesoscopic structure of the insensitive silica glass. The optical glass has the characteristics of a high laser damage growth threshold, slow laser damage growth, and insensitivity to the environment. At the same time, the new insensitive optical glass is created based on silica as the base material and the fusion of the preparation method, improving the processing quality of the optical glass.

[0025] 2. The present invention improves the anti-laser damage performance of the insensitive silica optical glass by increasing the laser damage growth threshold and reducing the laser damage growth rate, making the insensitive silica optical glass more widely used in high-energy laser systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0027] Figure 1 is a schematic flow chart of the preparation method of the present invention;

[0028] Figure 2 is a schematic diagram of the synthesis of insensitive silica in the preparation method of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0030] A preparation method for insensitive silica optical glass for high-energy laser systems, as Figure 1 and Figure 2 shown, the insensitive silica optical glass for high-energy laser systems contains a mesoscopic structure formed by the solidification of nano-silica particles. The silica particles are homogeneous at the optical level, while the mechanical level is a composite structure of a porous network and a dense region.

[0031] The preparation method includes the following steps:

[0032] S1. Using metal alkoxide and phosphoric acid as reaction precursors, under the conditions of silicate, catalyst, and water, hydrolysis polymerization is carried out to synthesize silica spherical particle sol by the liquid-phase method;

[0033] S2. Adjust parameters such as the concentration of reactants, reaction temperature, and reaction rate to control the size of the spherical silica particles within the range of 50 - 200 nm;

[0034] S3. After the sol is gelled, use the supercritical drying technology for solidification and molding;

[0035] S4. Perform heat treatment on the solidified gel. By regulating the heat treatment temperature of 300 - 1000 °C, heat treatment time of 1 - 36 h, and the heat treatment process, including step - wise temperature increase or constant temperature, obtain insensitive silica optical glasses with different sintering degrees;

[0036] S5. Place the insensitive silica optical glasses with different sintering degrees on a laser damage test platform, and then use a 351 nm ultraviolet laser to test the laser damage threshold and laser damage growth threshold of the insensitive silica glass.

[0037] The metal alkoxide includes methyl orthosilicate, and the addition amount of phosphoric acid is 0.1 - 0.6% of the total mass of the precursors.

[0038] The medium for supercritical drying is liquid CO₂, the drying pressure is 7 - 12 MPa, and the temperature is 32 - 50 °C.

[0039] The heat treatment process includes:

[0040] The first stage: Heat up to 300 - 600 °C at a rate of 5 - 8 °C / min and hold for 2 - 12 h to remove organic residues;

[0041] The second stage: Heat up to 800 - 1000 °C at a rate of 1 - 3 °C / min and hold for 1 - 18 h to achieve densification.

[0042] The laser irradiation conditions are: laser wavelength is 351 nm, pulse width is 8 ns, pulse frequency is 60 Hz, pulse energy is 18 mJ, and irradiation time is 10 min.

[0043] The laser damage test includes: laser damage threshold ≥ 15 J / cm 2 ; damage growth threshold ≥ 8 J / cm 2 ; damage growth coefficient ≤ 1.

[0044] Among them, during high - energy laser irradiation damage, the damage pit is plastic damage and the damage morphology is smooth; during subsequent high - energy laser irradiation, the damage pit will not show damage growth or the damage growth is slow.

[0045] The mesoscopic structure of the insensitive silica optical glass is a composite structure of a porous network and a dense region, and the controllable range of porosity is 5% - 10%.

[0046] Application of the optical glass produced by the preparation method of the insensitive silica optical glass for high - energy laser systems in high - energy laser systems.

[0047] When the present invention is in use, using tetraethyl orthosilicate and phosphoric acid as precursors, hydrolysis occurs at pH = 4 and 50 °C to generate a sol; supercritical drying is carried out under the conditions of CO2, 60 °C, and 10 MPa, and heat treatment is carried out at 1000 °C for 5 hours; the initial laser damage threshold of the obtained glass is 28 J / cm 2 , and the growth threshold is 17 J / cm 2 , and the growth coefficient is 0.08 μm / pulse, obtaining a desensitized silica optical glass. By adopting the liquid-phase synthesis technology, the purity of the desensitized silica glass is improved, and the mesoscopic structure of the desensitized silica glass is optimized. The preparation conditions of the liquid-phase method are mild, without involving high temperature and high pressure, and there is no need to use containers and instruments made of inactive precious metals such as platinum. At the same time, the combination of the liquid-phase method, supercritical drying, and controllable heat treatment can control the particle size of the silica glass, and the subsequent curing process is convenient for adjusting the strength of the binding force between particles, thereby realizing the optimized adjustment of the mesoscopic structure of the glass;

[0048] By increasing the laser damage growth threshold and reducing the laser damage growth rate, the anti-laser damage performance of the long-life high-damage increment threshold desensitized silica glass is improved. The new type of ultraviolet desensitized optical glass has significant advantages in high-energy laser devices:

[0049] (1) The laser damage growth threshold is high. When an initial damage appears on the component, due to the high laser damage growth threshold of the component, damage growth may not occur in the subsequent laser irradiation of the component;

[0050] (2) The laser damage growth is slow. If laser damage growth occurs on the component, since the laser damage growth of the component is in a linear manner, the size of the damage pit grows slowly;

[0051] (3) The laser load capacity is improved, the damage speed of optical components is reduced, and the cost is lowered.

[0052] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed.

Claims

1. A preparation method of insensitive silica optical glass for a high-energy laser system, characterized in that, The glass contains a mesoscopic structure formed by the solidification of nano-silica particles. The silica particles are homogeneous at the optical level, while at the mechanical level, they are a composite structure of a porous network and a dense region.

2. The preparation method of the insensitive silica optical glass of the high-energy laser system according to claim 1, characterized in that, The preparation method includes the following steps: S1. Using metal alkoxide and phosphoric acid as reaction precursors, under the conditions of silicate ester, catalyst and water, hydrolysis polymerization is carried out to synthesize a silica spherical particle sol by the liquid phase method; S2. Adjust parameters such as the concentration of reactants, reaction temperature and reaction rate to control the size of the silica spherical particles within the range of 50 - 200 nm; S3. After the sol is gelated, supercritical drying technology is used for solidification and forming; S4. Heat treatment is carried out on the solidified gel. By controlling the heat treatment temperature of 300 - 1000 °C, heat treatment time of 1 - 36 h and the heat treatment process, including stepwise heating or constant temperature, insensitive silica optical glass with different sintering degrees is obtained; S5. The insensitive silica optical glass with different sintering degrees is placed on a laser damage test platform, and then the laser damage threshold and laser damage growth threshold of the insensitive silica glass are tested using a 351 nm ultraviolet laser.

3. The method for preparing the insensitive silica optical glass of the high-energy laser system according to claim 2, wherein The metal alkoxide includes methyl orthosilicate, and the addition amount of phosphoric acid is 0.1 - 0.6% of the total mass of the precursors.

4. The method for preparing the insensitive silica optical glass of the high-energy laser system according to claim 2, wherein, The medium for supercritical drying is liquid CO2, the drying pressure is 7 - 12 MPa, and the temperature is 32 - 50 °C.

5. The preparation method of the insensitive silica optical glass of the high-energy laser system according to claim 2, characterized in that, The heat treatment process includes: The first stage: heating at 5 - 8 °C / min to 300 - 600 °C and holding for 2 - 12 h to remove organic residues; The second stage: heating at 1 - 3 °C / min to 800 - 1000 °C and holding for 1 - 18 h to achieve densification.

6. The preparation method of the insensitive silica optical glass of the high-energy laser system according to claim 2, characterized in that, The laser irradiation conditions are: laser wavelength is 351 nm, pulse width is 8 ns, pulse frequency is 60 Hz, pulse energy is 18 mJ, and irradiation time is 10 min.

7. The preparation method of the insensitive silica optical glass of the high-energy laser system according to claim 2, characterized in that, The laser damage test includes: the laser damage threshold ≥ 15 J / cm 2 , the damage growth threshold ≥ 8 J / cm 2 , and the damage growth coefficient ≤ 1.

8. The preparation method of the insensitive silica optical glass of the high-energy laser system according to claim 2, characterized in that The mesoscopic structure of the insensitive silica optical glass is a composite structure of a porous network and a dense region, and the controllable range of porosity is 5% - 10%.

9. Application of the optical glass produced by the preparation method of the insensitive silica optical glass of the high-energy laser system according to any one of claims 2 - 8 in the high-energy laser system.

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