High-imaging-resolution optical glass original sheet for medium-free holographic imaging element

Abstract

The invention discloses a high-imaging-resolution optical glass original sheet for a medium-free holographic imaging element, and particularly relates to the field of optical glass original sheets. Comprising the following components in parts by mass: 100-125 parts of silicon dioxide, 12-25 parts of boron oxide, 10-18 parts of sodium oxide, 5-12 parts of aluminum oxide, 6-15 parts of strontium oxide, 2-6 parts of magnesium oxide, 1-4 parts of calcium oxide, 0.8-2.5 parts of cerium oxide and 0.2-1.0 part of praseodymium oxide. The rare earth ion doped structure formed by cerium oxide and praseodymium oxide is embedded into a silicon oxide-boron oxide network structure jointly constructed by silicon dioxide and boron oxide in the glass melting process to form a group of valence state energy trapping structures. By constructing a free-state ion migration suppression network under the combined action of a rare earth ion energy trapping structure and a confinement framework mechanism, the problem of nonlinear amplification of pattern boundary fuzziness and misreading caused by high-frequency scattering induced by trace impurities in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of optical glass original sheets, and more particularly to a high-imaging-resolution optical glass original sheet for medium-free holographic imaging elements. Background Art

[0002] In the current construction of medium-free holographic imaging elements, optical glass substrates serve as the fundamental carrier for interference pattern propagation and phase control. The purity of the material directly determines the image resolution and the recognition accuracy of structural boundaries. To balance cost and processing adaptability, existing technologies widely use neutral or slightly alkaline silicate glasses based on sodium oxide-boron oxide-silicon dioxide. However, this type of glass formulation has a severely underestimated technical risk that is particularly critical in high-precision imaging tasks: during high-temperature annealing or laser processing for holographic pattern construction, trace amounts of impurity ions such as trivalent iron, trivalent chromium, and divalent nickel in the glass can form subnanometer-scale oxide clusters due to thermal diffusion and local energy trapping. Although these clusters have a weak effect on the transmittance in the visible region and are not detectable to the naked eye, they exhibit high-frequency background scattering behavior in the wavelength range of 400 to 470 nanometers, especially in the blue and near-violet regions; This type of scattering is not a uniform atomization effect, but rather an extremely subtle but spatially unstable phase disturbance field. This often results in enhanced superposition along the boundaries of the interference pattern, causing blurred halos at the edges of the holographic image and making it difficult to accurately decode the microstructure boundaries. This phenomenon not only affects the edge sharpness of the pattern but also causes local information redundancy or phase misalignment in 3D reconstruction, ultimately leading to misjudgment by the recognition algorithm or false touches in interactions. In actual engineering, this high-frequency scattered white fog phenomenon is often mistaken for laser system instability or recording algorithm errors. Because it is weakly random, it is difficult to track the root cause. In summary, the formula design of optical glass raw materials in the existing technology, which is centered on the sodium oxide-boron oxide-silicon dioxide system, has the following problems when it comes to high-resolution medium-free holographic imaging: the nonlinear light scattering amplification mechanism of trace impurities at the micro-optical scale is not suppressed, resulting in systematic boundary blurring and the risk of pattern misreading. This problem is difficult to avoid with existing process optimization and traditional purification methods, and constitutes a bottleneck restricting the holographic image resolution capability. Summary of the Invention

[0003] In order to overcome the above-mentioned defects of the prior art, an embodiment of the present invention provides a high-imaging resolution optical glass original for a medium-free holographic imaging element, by constructing a free-state ion migration inhibition network that is jointly acted upon by a rare earth ion trapping structure and a confined skeleton mechanism, so as to solve the nonlinear amplification problem proposed in the above-mentioned background technology, in which trace impurities induce high-frequency scattering, resulting in blurred pattern boundaries and misreading.

[0004] To achieve the above object, the present invention provides the following technical solution: a high-resolution optical glass substrate for medium-free holographic imaging elements; the optical glass substrate is composed of the following components in the following mass ratios: 100-125 parts of silicon dioxide, 12-25 parts of boron oxide, 10-18 parts of sodium oxide, 5-12 parts of aluminum oxide, 6-15 parts of strontium oxide, 2-6 parts of magnesium oxide, 1-4 parts of calcium oxide, 0.8-2.5 parts of cerium oxide, and 0.2-1.0 parts of praseodymium oxide; The rare earth ion doping structure composed of cerium oxide and praseodymium oxide is embedded in the silicon-oxygen-boron-oxygen network structure constructed by silicon dioxide and boron oxide during the glass melting process, forming a set of valence energy trapping structures; the valence energy trapping structures are used to constrain the migration paths of free ions formed by trivalent iron, trivalent chromium, and divalent nickel, and position the free ions at stable node sites in the silicon-oxygen-boron-oxygen network structure.

[0005] In a preferred embodiment, the strontium oxide and magnesium oxide cooperate to form a glass structure intermediate, and induce the formation of a skeleton structure during the thermal annealing process, and the skeleton structure is used to construct a physical boundary that limits the migration path of free ions; The sodium oxide and aluminum oxide are combined to control the non-bridging oxygen concentration and the proportion of the bridging oxygen connection structure in the glass network according to a set ratio, thereby forming a diffusion environment that limits the migration ability of alkali metal ions; Under the synergistic effect of various components, the glass sheet outputs a uniformly distributed area of ​​the refractive index field within the imaging wavelength range of 380-470 nanometers, which is used to limit the path superposition behavior of high-frequency stray signals and establish a phase consistency condition at the pattern boundary.

[0006] In a preferred embodiment, the mass ratio of cerium oxide to praseodymium oxide is 3:1-4:1, and the mass ratio of cerium oxide to praseodymium oxide constructs a rare earth multivalent trap structure, which is used to correspond to the excited state migration behavior of trivalent iron and trivalent chromium, respectively, and form a double trap coupling reaction site for them.

[0007] In a preferred embodiment, the strontium oxide and magnesium oxide construct nanoscale crystalline discontinuous regions during the molten phase cooling process, and the crystalline discontinuous regions form a confined diffusion network, blocking the continuous migration of divalent metal ions by physical constraints.

[0008] In a preferred embodiment, the mass ratio of sodium oxide to aluminum oxide is 2:1-2.5:1, and the mass ratio of sodium oxide to aluminum oxide is used to regulate the bridging oxygen bond breakage threshold, construct a stable network region where bridging oxygen and non-bridging oxygen coexist, and form a structural domain with a charge migration blocking effect.

[0009] In a preferred embodiment, 1-5 parts of zinc oxide are also included. The zinc oxide and boron oxide jointly form a glass network structure during the melting stage, which is used to regulate the distribution uniformity of boroxy units in the structure and construct a chain structure region in the glass matrix with the ability to regulate local charge density.

[0010] In a preferred embodiment, the cerium oxide exists in the form of a tetravalent ion state, and the atmosphere during the melting process is: controlling the oxygen partial pressure to be 0.1-0.25 standard atmospheric pressure; the atmosphere is used to suppress the valence state transfer behavior of rare earth ions and construct a stable energy level trap structure under redox equilibrium.

[0011] In a preferred embodiment, the optical glass original sheet is subjected to an annealing process after being formed, the annealing temperature is controlled at 490-520 degrees Celsius, the annealing duration is not less than 90 minutes, and the structural domain stress gradient during the annealing process is less than 1.2 MPa to achieve spatial uniformity of the refractive index in the original sheet.

[0012] Technical effects and advantages of the present invention: By constructing a valence-trapped energy structure formed by embedding cerium oxide and praseodymium oxide into a silicon-oxygen-boron-oxygen network structure, the free-state ion migration path formed by trivalent iron, trivalent chromium, and divalent nickel is bounded, suppressing the local phase field disturbance induced by them within the imaging band. This eliminates the blurred halo phenomenon caused by high-frequency scattering on the pattern boundary of the white light area, and realizes the stable decoding capability of the high-resolution medium-free imaging system for the microstructure boundary. The framework structure synergistically induced by strontium oxide and magnesium oxide generates a stable confined network during the annealing process, which is used to establish the spatial physical boundary of the divalent ion migration path, preventing the formation of inhomogeneous phase disturbance regions due to thermal diffusion, thereby improving the optical purity and refractive index uniformity of the imaging area; The diffusion environment formed by sodium oxide and aluminum oxide in a mass ratio of 2:1–2.5:1 effectively controls the bridging oxygen bond breakage threshold, stabilizes the non-bridging oxygen-bridging oxygen coexistence region, structurally creates a migration barrier for alkali metal free ions, and reduces the local refractive index shift caused by background charge disturbances. The rare earth ion trap structure constructed based on the mass ratio of cerium oxide and praseodymium oxide corresponds to the excited state energy levels of trivalent iron and trivalent chromium, respectively, realizing a multi-level locking configuration of coupled reaction sites and improving the capture ability of polyvalent metal ions. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0014] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0015] Refer to the instruction manual Figure 1 , an optical glass original sheet with high imaging resolution for a medium-free holographic imaging element according to an embodiment of the present invention; The optical glass raw sheet is composed of the following components in the following mass ratios: 100-125 parts of silicon dioxide, 12-25 parts of boron oxide, 10-18 parts of sodium oxide, 5-12 parts of aluminum oxide, 6-15 parts of strontium oxide, 2-6 parts of magnesium oxide, 1-4 parts of calcium oxide, 0.8-2.5 parts of cerium oxide, and 0.2-1.0 parts of praseodymium oxide; The rare earth ion doping structure composed of cerium oxide and praseodymium oxide is embedded in the silicon-oxygen-boron-oxygen network structure constructed by silicon dioxide and boron oxide during the glass melting process, forming a set of valence energy trapping structures; the valence energy trapping structures are used to constrain the migration paths of free ions formed by trivalent iron, trivalent chromium, and divalent nickel, and locate the free ions at stable node sites in the silicon-oxygen-boron-oxygen network structure; It should be noted that among the components of the optical glass raw sheet, silicon dioxide serves as a glass network former to provide the main structural framework, boron oxide is introduced to form a boron-oxygen chain for adjusting the network structure flexibility and spectral response window, sodium oxide and aluminum oxide constitute a basic modification system for regulating the ratio of bridging oxygen and non-bridging oxygen structures in the glass network to control the migration ability of alkali metal ions, strontium oxide and magnesium oxide are used to construct the glass intermediate structure and induce the formation of a confined skeleton during the melting and annealing process to limit the diffusion path of impurity ions, calcium oxide is introduced as a stabilizer to regulate melt viscosity and molding performance, cerium oxide and praseodymium oxide are embedded in the network nodes as rare earth ion doping sources to form energy-trapping structures for capturing impurity ions such as trivalent iron, trivalent chromium, and divalent nickel to suppress their induced high-frequency scattering behavior; this formula type is constructed based on a borosilicate system, with silicon dioxide as the main framework and an appropriate amount of boron component introduced to enhance the network response regulation ability. On this basis, the mass fraction range of each modified component is set according to its structural action limit to ensure that the glass forms an optical functional area with refractive index uniformity, impurity migration limitation and imaging boundary stability in the 380-470 nanometer band; Among them, cerium oxide and praseodymium oxide, as high-valent rare earth ions, are doped into the silicon-oxygen-boron-oxygen network structure constructed by silicon dioxide and boron oxide during the glass melting process, forming a trapped energy structure with valence energy level capture function, which is used to constrain the paths of migrating impurity ions such as trivalent iron, trivalent chromium, and divalent nickel and fix them in stable sites in the network structure, thereby establishing an ion migration shielding mechanism within the material system to suppress high-frequency scattering interference; in addition, in terms of formula selection, the combination of cerium and praseodymium can cover the excited state energy level range of multivalent impurity ions, and its mass fraction is controlled between 0.8-2.5 parts and 0.2-1.0 parts to ensure the ion capture density and spatial uniformity of the trapped energy structure, while avoiding valence disturbance of the main network structure, ensuring that the glass has local energy level regulation function and does not introduce new migration channels.

[0016] The strontium oxide and magnesium oxide cooperate to form a glass structure intermediate, and induce the formation of a skeleton structure during thermal annealing, wherein the skeleton structure is used to construct a physical boundary that limits the migration path of free ions; The sodium oxide and aluminum oxide are combined to control the non-bridging oxygen concentration and the proportion of the bridging oxygen connection structure in the glass network according to a set ratio, thereby forming a diffusion environment that limits the migration ability of alkali metal ions; Under the synergistic effect of various components, the glass substrate outputs a uniformly distributed area of ​​the refractive index field within the imaging wavelength range of 380-470 nanometers, which is used to limit the path superposition behavior of high-frequency stray signals and establish a phase consistency condition at the pattern boundary; It should be noted that strontium oxide and magnesium oxide synergistically constitute a glass structure intermediate and induce the formation of a skeleton structure during the thermal annealing process, which is used to construct a physical boundary that restricts the migration path of free ions. At the same time, sodium oxide and aluminum oxide regulate the non-bridging oxygen concentration and the composition ratio of the bridging oxygen connection structure in the glass network according to a set ratio, forming an environment where the migration and diffusion of alkali metal ions are restricted. Therefore, under the synergistic action of each component, the uniform output of the refractive index field is achieved and the path superposition of high-frequency stray signals is suppressed, and the phase consistency condition of the pattern boundary is established within the imaging band; the system uses 6-15 parts of strontium oxide and 2-6 parts of magnesium oxide to control the nucleation density and annealing stress distribution of the skeleton structure, and uses 10-18 parts of sodium oxide and 5-12 parts of aluminum oxide to form an adaptive charge migration blocking zone, and ensures optical uniformity and spatial phase stability in the wavelength range of 380-470 nanometers through overall network structure adjustment.

[0017] The mass ratio of cerium oxide to praseodymium oxide is 3:1-4:1, and the mass ratio of cerium oxide to praseodymium oxide constructs a rare earth multivalent trap structure, which is used to correspond to the excited state migration behavior of trivalent iron and trivalent chromium, respectively, and form a double trap coupling reaction site for them; It should be noted that the mass ratio of cerium oxide to praseodymium oxide is controlled in the range of 3:1-4:1. The rare earth multivalent trap structure formed is used to correspond to the excited state migration behavior of trivalent iron and trivalent chromium in the glass network, respectively, and construct a double-trap coupling reaction site through the energy level docking relationship, so as to realize path recognition and energy level capture of multivalent impurity ions, and inhibit their migration and accumulation behavior in local areas; the mass ratio is set based on the electronic configuration and redox stability range of cerium and praseodymium. Cerium is mainly used in the tetravalent state to form a deep energy level trap with trivalent iron, and praseodymium participates in the energy level coupling capture of trivalent chromium in the trivalent state. The ratio of the two controls the trap density to cover different impurity transition paths without causing local charge imbalance, thereby maintaining the phase stability and impurity shielding effect of the glass system during heat treatment and imaging.

[0018] The strontium oxide and magnesium oxide construct nanoscale discontinuous crystalline regions during the cooling process of the molten phase, and the discontinuous crystalline regions form a confined diffusion network, which blocks the continuous migration of divalent metal ions by physical constraints; It should be noted that strontium oxide and magnesium oxide work synergistically during the cooling process of the molten phase to form nanoscale crystalline discontinuous regions, which construct a confined diffusion network in the glass matrix, used to block the continuous migration path of divalent metal ions through physical space constraints, thereby cutting off the mechanism of impurities forming enrichment centers in a local area; this structure relies on 6-15 parts of strontium oxide to provide a skeleton rigidity basis, and 2-6 parts of magnesium oxide to regulate the nucleation density and crystal domain size. The ratio of the two induces the formation of discontinuous crystal phase boundaries during the cooling process, limits the ion diffusion scale and establishes a path discontinuity interface, so that the migrating ions cannot form a stable channel in the spatial structure, reducing the probability of trajectory overlap and the risk of phase disturbance in the holographic imaging area.

[0019] The mass ratio of sodium oxide to aluminum oxide is 2:1-2.5:1. The mass ratio of sodium oxide to aluminum oxide is used to regulate the bridging oxygen bond breakage threshold, construct a stable network region where bridging oxygen and non-bridging oxygen coexist, and form a structural domain with a charge transfer blocking effect. It should be noted that the mass ratio of sodium oxide to aluminum oxide is controlled in the range of 2:1-2.5:1. This ratio is used to regulate the breaking threshold of the bridging oxygen bond in the glass network. By adjusting the distribution state of aluminum oxide tetrahedrons and alkali metal ions, a structural region where bridging oxygen and non-bridging oxygen coexist is constructed, and a structural domain with a blocking effect on charge migration is formed in this region; this ratio is set to provide positively charged network modification sites with 5-12 parts of aluminum oxide to enhance the bridging oxygen connection ability, and to provide a non-bridging oxygen source with 10-18 parts of sodium oxide to control the distribution uniformity of alkali metal ions and the probability of migration channel formation, thereby constructing a charge diffusion barrier structure with a stable spatial configuration and low migration flux in the glass matrix, which is used to suppress the lateral drift of alkali metal ions and the interference of overall conductivity changes on the phase consistency of holographic imaging.

[0020] It also includes 1-5 parts of zinc oxide, which participates in forming a glass network structure with boron oxide during the melting stage, and is used to control the distribution uniformity of borane units in the structure and construct a chain structure region in the glass matrix with the ability to control local charge density; It should be noted that zinc oxide is introduced into the glass system in a mass fraction of 1-5 parts, and participates in constructing the glass network structure together with boron oxide during the melting stage, which is used to regulate the distribution uniformity of boroxy units in the overall structure, so that they form chain-like connection units with stable structure and non-segregation in space, and establish structural segments with charge density regulation capabilities in local areas, which are used to alleviate local phase disturbances caused by charge concentration in the boroxy network; this component setting participates in charge compensation and structural filling in the boroxy chain segments through zinc ions, so that the originally more active boroxy units obtain higher distribution control in the three-dimensional structure, thereby improving the charge balance of the network on a microscopic scale, weakening the dipole interference in the high-frequency response area, and improving the phase stability and resolution consistency of the imaging area.

[0021] The cerium oxide exists in the form of a tetravalent ion, and the atmosphere during the melting process is: the oxygen partial pressure is controlled to be 0.1-0.25 standard atmospheric pressure; the atmosphere is used to suppress the valence state transfer behavior of the rare earth ions and construct a stable energy level trap structure under redox equilibrium; It should be noted that cerium oxide exists stably in the form of a tetravalent ion during the glass melting process. The melting atmosphere maintains the rare earth ion system in a redox equilibrium state by controlling the oxygen partial pressure within the range of 0.1-0.25 standard atmospheric pressure, thereby avoiding valence state transition of cerium oxide under high temperature conditions, thereby ensuring that it stably forms trapped energy state sites corresponding to the energy levels of trivalent iron ions in the network structure; this atmosphere control strategy is based on the requirement of tetravalent cerium for electron capture ability, and the oxygen partial pressure setting range is used to constrain the valence state transfer threshold of cerium ions, avoiding the formation of trivalent cerium that causes energy level offset or failure of the trapped energy structure, thereby achieving valence state stability and energy level functional continuity of the rare earth trapped energy structure in the glass body, and providing the necessary energy band matching conditions for subsequent impurity ion path capture.

[0022] After the optical glass original sheet is formed, an annealing process is performed, the annealing temperature is controlled at 490-520 degrees Celsius, the annealing duration is not less than 90 minutes, and the stress gradient of the structural domain is less than 1.2 MPa during the annealing process, so as to achieve spatial uniformity of the refractive index in the original sheet; It should be noted that the optical glass raw sheet is subjected to an annealing process after forming, and the annealing temperature is set to 490-520 degrees Celsius, and the duration is not less than 90 minutes. During the annealing process, the structural domain stress gradient is controlled below 1.2 MPa, which is used to release the structural residual stress accumulated inside the glass during the melting and cooling stages, and ensure that the refractive index field remains uniformly distributed on a spatial scale; the above parameter settings are determined based on the softening temperature zone of the skeleton domain composed of strontium oxide, magnesium oxide, and aluminum oxide in the glass intermediate structure. 490 degrees Celsius is the starting temperature for glass network relaxation, and 520 degrees Celsius is close to the upper limit of loosening oxygen connections in the amorphous structure, ensuring that the stress release process is sufficient but does not induce phase structure rearrangement. The holding time of more than 90 minutes is combined with the stress gradient limit below 1.2 MPa to jointly establish a distortion-free optical domain in the glass body, preventing refractive index drift and optical distortion caused by local stress in subsequent holographic imaging.

[0023] Table 1: Relationship between rare earth doping ratio and iron ion migration residue

[0024] Table 2: Annealing parameters and refractive index uniformity response

[0025] It should be noted that, for the relationship between rare earth doping ratio and iron ion migration residue in Table 1, the experimental setting uses the mass fraction ratio of cerium oxide to praseodymium oxide as the main variable, and sets four groups of doping conditions (samples A–D) to verify the capture effect of the energy trap structure formed by the rare earth ions in the silicon-oxygen-boron-oxygen network structure on the migration behavior of trivalent iron ions; among them, the rare earth mass ratio is set based on Ce 4+Deep trapping ability for iron ions and Pr 3+ For the synergistic effect of shallow energy level coupling, the ratio range covers the 3:1–4:1 doping window proposed in this scheme, namely samples A (2:0.6, 3.3:1), B (1.8:0.5, 3.6:1), C (1.5:0.4, 3.75:1) and D (0.8:0.2, 4:1); During the melting process, the oxygen partial pressure of each sample was controlled at 0.1–0.25 standard atmospheres to ensure that cerium oxide existed in a tetravalent state, forming a valence-trapped energy structure. After the melting, the glass sheets were subjected to a laser-induced diffusion test to quantitatively analyze the lateral migration behavior of iron ions under thermal load. The sampling window was 50 microns below the glass surface, and the scanning area was 1 cm. 2 The cumulative concentration of iron ions in the migration area was detected by plasma emission mass spectrometry, and the residual density of iron ions was calculated by integrating the migration depth, expressed in ng / cm 2 For units; Sample A has the highest cerium oxide doping amount (2 parts), but the Pr ratio is low, and the trapped energy structure is in the capture of Ce 4+ Under the dominant effect, a relatively deep trap was formed. Due to the insufficient valence matching window, some iron ions escaped, resulting in a residual value of 4.48 ng / cm 2 The C sample is the best combination (1.5:0.4, 3.75:1), forming a double-trap coupling structure under the synergistic effect of Ce / Pr energy levels, with the largest capture window and a migration residue of only 2.57 ng / cm 2 The D sample has the lowest doping level, the trap density is insufficient, and only boundary state traps are formed. The migration control fails, and the residue rises to 5.70 ng / cm 2 , which verifies the necessity of setting the upper and lower limits of doping ratio and number of parts.

[0026] Based on the annealing parameters and refractive index uniformity response table in Table 2, this experiment used annealing temperature and time as the primary control variables. Combined with the results of testing the stress release state and refractive index spatial distribution within the optical glass substrate under different annealing conditions, this experiment verified the supporting relationship between the confined skeleton structure and the stress control window on imaging phase stability. The four groups of samples (A–D) were all prepared using a unified formulation, differing only in the annealing parameters: Sample A was set at 490°C for 90 minutes; Samples B and C were 500°C and 510°C, respectively, for 100 minutes; and Sample D was set at 520°C for 90 minutes.

[0027] After forming, each set of glass sheets was immediately annealed. By setting the holding temperature and time, the residual stress release process caused by rapid cooling in the internal structural domain of the glass was controlled. The stress gradient was obtained by polarized light interferometry combined with stress birefringence testing. The glass cross section was sliced ​​along the thickness direction, the photoelastic image was recorded, and the maximum principal stress variation range was calculated. The structural stress gradient was output in MPa. The refractive index uniformity test was conducted using spatial interferometry tomography. The refractive index fluctuation amplitude of each 0.1mm grid in the effective imaging area of ​​the glass was scanned, and the maximum deviation was calculated. The results were expressed as 10 -4 Output as unit; The experimental results show that samples B and C (annealed at 500℃ and 510℃, respectively, and kept warm for 100 minutes) exhibit the lowest stress gradient (0.84 / 0.83MPa) and the smallest refractive index deviation (1.34×10 -4 and 1.25×10 -4 ), verifying that the phase field of the confined skeleton structure tends to be uniform after the network stress is released in the intermediate temperature zone; although sample A meets the lower limit (490℃, 90 minutes), the stress release is not complete, resulting in the gradient increasing to 1.11MPa, and the refractive index fluctuation remains at 1.34×10 -4 Although the stress of sample D is fully released (0.83 MPa), the annealing temperature is close to the upper limit of the framework transformation temperature range of the silicon-oxygen-boron-oxygen network (520°C), resulting in local structural deconstruction and reorganization, which triggers the rearrangement of the refractive index field, and its maximum deviation rises to 1.98×10 -4 , indicating that although stress is minimized at high temperature, optical uniformity cannot be guaranteed, which proves that the upper limit of the annealing temperature window (490–520°C) proposed in this scheme is reasonable; In summary, the experimental parameters and measurement results listed in Table 2 truly reflect the inherent logic between the skeleton structure, stress release mechanism, and optical response set in this scheme. In particular, they prove that the technical settings of annealing time ≥ 90 minutes, stress gradient ≤ 1.2 MPa, and temperature not exceeding 520°C are stable and necessary.

[0028] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high-resolution optical glass substrate for a dielectric-free holographic imaging element, characterized by: The optical glass raw sheet is composed of the following components in the following mass ratios: 100-125 parts of silicon dioxide, 12-25 parts of boron oxide, 10-18 parts of sodium oxide, 5-12 parts of aluminum oxide, 6-15 parts of strontium oxide, 2-6 parts of magnesium oxide, 1-4 parts of calcium oxide, 0.8-2.5 parts of cerium oxide, and 0.2-1.0 parts of praseodymium oxide; The rare earth ion doping structure composed of cerium oxide and praseodymium oxide is embedded in the silicon-oxygen-boron-oxygen network structure constructed by silicon dioxide and boron oxide during the glass melting process, forming a set of valence energy trapping structures; the valence energy trapping structures are used to constrain the migration paths of free ions formed by trivalent iron, trivalent chromium, and divalent nickel, and position the free ions at node sites in the silicon-oxygen-boron-oxygen network structure.

2. The high-resolution optical glass substrate for a medium-free holographic imaging element according to claim 1, characterized in that: The strontium oxide and magnesium oxide cooperate to form a glass structure intermediate, and induce the formation of a skeleton structure during the thermal annealing process; The sodium oxide and aluminum oxide are combined to control the non-bridging oxygen concentration and the proportion of the bridging oxygen connection structure in the glass network according to a set ratio, thereby forming a diffusion environment that limits the migration ability of alkali metal ions; Under the synergistic effect of various components, the glass original sheet outputs a distribution area of ​​a refractive index field within the imaging wavelength range of 380-470 nanometers.

3. The high-resolution optical glass substrate for a medium-free holographic imaging element according to claim 2, characterized in that: The mass ratio of cerium oxide to praseodymium oxide is 3:1-4:1, and the mass ratio of cerium oxide to praseodymium oxide constructs a rare earth multivalent trap structure, which is used to correspond to the excited state migration behavior of trivalent iron and trivalent chromium, respectively, and form a coupling reaction site for them.

4. The high-resolution optical glass substrate for a medium-free holographic imaging element according to claim 3, characterized in that: The strontium oxide and magnesium oxide construct nanoscale crystalline discontinuous regions during the cooling process of the molten phase. The crystalline discontinuous regions form a confined diffusion network, which blocks the continuous migration of divalent metal ions by physical constraints.

5. The high-resolution optical glass substrate for medium-free holographic imaging elements according to claim 4, characterized in that: The mass ratio of sodium oxide to aluminum oxide is 2:1-2.5:

1. The mass ratio of sodium oxide to aluminum oxide is used to regulate the bridging oxygen bond breaking threshold, construct a stable network region where bridging oxygen and non-bridging oxygen coexist, and form a structural domain with a charge migration blocking effect.

6. The high-resolution optical glass substrate for a medium-free holographic imaging element according to claim 5, characterized in that: It also includes 1-5 parts of zinc oxide, which participates in forming the glass network structure together with boron oxide during the melting stage.

7. The high-resolution optical glass substrate for medium-free holographic imaging elements according to claim 6, characterized in that: The cerium oxide exists in the form of a tetravalent ion state. The atmosphere during the melting process is: the oxygen partial pressure is controlled to be 0.1-0.25 standard atmospheric pressure; the atmosphere is used to suppress the valence state transfer behavior of rare earth ions.

8. The high-resolution optical glass substrate for medium-free holographic imaging elements according to claim 7, characterized in that: After the optical glass original sheet is formed, an annealing process is performed, the annealing temperature is controlled at 490-520 degrees Celsius, the annealing duration is not less than 90 minutes, and the structural domain stress gradient during the annealing process is less than 1.2 MPa.

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