Chalcogenide glass with negative refractive index temperature coefficient as well as preparation method and application of chalcogenide glass

Abstract

The invention provides chalcogenide glass with a negative refractive index temperature coefficient as well as a preparation method and application of the chalcogenide glass, and belongs to the technical field of infrared chalcogenide glass. The chemical formula of the chalcogenide glass provided by the invention is As < x > Se < 100-x >, and x ranges from 20 to 36. By optimizing the chemical formula of the chalcogenide glass, the refractive index and the dn / dT value of the chalcogenide glass can be controlled, and the dn / dT value of the chalcogenide glass is negative, so that the characteristic that the refractive index generated by a conventional lens changes along with the temperature can be effectively compensated, and the heat effect is reduced or even eliminated; the linear refractive index value of the chalcogenide glass provided by the invention is reduced along with the increase of the dn / dT value, so that the chalcogenide glass can be used as a passive athermalization lens element in an infrared system, and is of great significance to athermalization of the system. The result of the embodiment shows that the dn / dT value of the chalcogenide glass provided by the invention is-45 to-19 ppm / K, and the refractive index of the chalcogenide glass is 2.61 to 2.68.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of infrared chalcogenide glass, in particular to a chalcogenide glass with negative refractive index temperature coefficient and a preparation method and application thereof. BACKGROUND

[0002] Infrared thermal imaging technology has developed rapidly and has been widely used in various fields of military and civilian, such as infrared homing head system, driving assistance system, fire monitoring, biological medicine and industrial detection, etc. The importance of athermal infrared optical system is increasing, which can ensure the stability and reliability of optical performance and promote the development and application of more high-performance optical devices. The glass with negative refractive index temperature coefficient (-dn / dT) can effectively compensate the refractive index change with temperature of conventional lenses, reduce or even eliminate thermal effects, and is a key component for passive athermalization of the system. This passive athermalization does not need to introduce moving elements and does not need power supply, and has the advantages of small size, light weight, simple structure, stable optical axis and high reliability. For infrared systems, the main lenses are Ge (396 ppm / ℃), Si (160 ppm / ℃), ZnS (68 ppm / ℃) and As 40 Se 60 (31.2 ppm / ℃), etc. The dn / dT of these lenses is a large positive value, and the temperature change range of most military infrared systems is relatively large. If there is no athermal design, the infrared system will produce serious thermal defocus, the imaging ability will decrease sharply, and the device performance will be seriously reduced. Therefore, the development of -dn / dT infrared materials is an important part of the development of high-performance infrared devices. LightPath Optical Instrument Co., Ltd. officially launched BDNL-4 in April 2024, which has dn / dT = -16.3 ppm / ℃ at 10 μm, but the glass composition is strictly confidential. This product will upgrade the existing athermalization system and have great economic and national defense and military value. Therefore, the development of infrared -dn / dT glass is of great significance to the existing optical system, but there is no related technical achievement in China. How to provide a chalcogenide glass with negative refractive index temperature coefficient has become a technical problem to be solved in the field. SUMMARY

[0003] The purpose of the present application is to provide a chalcogenide glass with negative refractive index temperature coefficient and a preparation method and application thereof. The dn / dT value of the chalcogenide glass with negative refractive index temperature coefficient provided by the present application is negative, which can effectively compensate the refractive index change with temperature of conventional lenses, reduce or even eliminate thermal effects.

[0004] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions:

[0005] The application provides a chalcogenide glass with a negative refractive index temperature coefficient, the chemical formula of the chalcogenide glass is As x Se 100-x wherein x is 20-36.

[0006] Preferably, the x is 25-35.

[0007] Preferably, the chalcogenide glass further comprises an additive element; the additive element comprises one or more of Ga, Ge, Sn, Sb, S and Te.

[0008] The application provides a preparation method of the chalcogenide glass with a negative refractive index temperature coefficient.

[0009] (1) performing vacuum heat treatment on raw materials of the chalcogenide glass to obtain the chalcogenide glass;

[0010] (2) performing annealing treatment on the chalcogenide glass obtained in the step (1) to obtain the chalcogenide glass with a negative refractive index temperature coefficient.

[0011] Preferably, the holding temperature of the vacuum heat treatment in the step (1) is 600-750 DEG C, the time of the vacuum heat treatment is 10-20 h, and the vacuum degree of the vacuum heat treatment is < 10 -4 Pa.

[0012] Preferably, the heating rate for heating to the holding temperature of the vacuum heat treatment in the step (1) is 60-120 DEG C / h.

[0013] Preferably, the cooling mode of the vacuum heat treatment in the step (1) is to first cool at a cooling rate of 50-120 DEG C / h to 250-450 DEG C, and then quickly cool to room temperature after standing for 20-60 min; the quick cooling mode is water cooling or quenching with a high-pressure air gun.

[0014] Preferably, the temperature of the annealing treatment in the step (2) is 10-20 DEG C lower than the transition temperature of the chalcogenide glass, the holding time of the annealing treatment is 3-10 h, and the cooling rate of the annealing treatment is 5-10 DEG C / h.

[0015] The application provides an application of the chalcogenide glass with a negative refractive index temperature coefficient or the chalcogenide glass prepared by the preparation method in military and civilian fields.

[0016] Preferably, the military and civilian fields include infrared homing head systems, driving auxiliary systems, fire control, biological medical treatment and industrial detection fields.

[0017] The application provides a chalcogenide glass with a negative refractive index temperature coefficient, the chemical formula of the chalcogenide glass is As x Se100-x wherein x is 20-36. The present application can control the refractive index and dn / dT value of the chalcogenide glass by optimizing the chemical formula of the chalcogenide glass, so that the dn / dT value of the chalcogenide glass is negative, thereby effectively compensating the refractive index change with temperature characteristics generated by a conventional lens, and reducing or even eliminating the thermal effect. The linear refractive index value of the chalcogenide glass provided by the present application decreases with the increase of the dn / dT value, which makes the chalcogenide glass can be used as a passive athermalization lens element in an infrared system, which is of great significance to the athermalization of the system. The results of the examples show that the dn / dT value of the chalcogenide glass provided by the present application is -45 to -19 ppm / K, and the refractive index is 2.61-2.68, which can effectively compensate the refractive index change with temperature characteristics generated by a conventional lens, and reduce or even eliminate the thermal effect. DETAILED DESCRIPTION

[0018] The present application provides a chalcogenide glass with negative refractive index temperature coefficient, the chemical formula of the chalcogenide glass is As x Se 100-x wherein x is 20-36.

[0019] In the present application, x is 20-36, preferably 25-35, more preferably 30. By adjusting the parameter x, the present application can control the amount of As in the chalcogenide glass, thereby controlling the refractive index and dn / dT value of the chalcogenide glass.

[0020] In the present application, the chalcogenide glass preferably further comprises an additive element; the additive element preferably comprises one or more of Ga, Ge, Sn, Sb, S and Te. The present application does not have special limitations on the specific amount of the additive element, which can be determined according to the required performance of the chalcogenide glass. By adding the additive element, the present application can adjust the refractive index, dn / dT value, glass transition temperature and thermal expansion coefficient of the chalcogenide glass without significantly changing the original-dn / dT performance.

[0021] The present application can control the refractive index and dn / dT value of the chalcogenide glass by optimizing the chemical formula of the chalcogenide glass, so that the dn / dT value of the chalcogenide glass is negative, thereby effectively compensating the refractive index change with temperature characteristics generated by a conventional lens, and reducing or even eliminating the thermal effect. The linear refractive index value of the chalcogenide glass provided by the present application decreases with the increase of the dn / dT value, which makes the chalcogenide glass can be used as a passive athermalization lens element in an infrared system, which is of great significance to the athermalization of the system.

[0022] The present application also provides a preparation method of the chalcogenide glass with negative refractive index temperature coefficient according to the above technical solution, comprising the following steps:

[0023] (1) vacuum heat treating the raw materials of the chalcogenide glass to obtain the chalcogenide glass;

[0024] (2) annealing the sulfur-based glass obtained in the step (1) to obtain a sulfur-based glass with a negative temperature coefficient of refractive index.

[0025] The present application obtains a sulfur-based glass by vacuum heat treatment of raw materials of the sulfur-based glass.

[0026] The present application does not have special limitations on the specific source and amount of the raw materials of the sulfur-based glass, and commercially available raw materials known to those skilled in the art can be used as long as the chemical composition of the sulfur-based glass meets the requirements.

[0027] In the present application, the raw materials of the sulfur-based glass are preferably first placed in a quartz tube, then subjected to heating and vacuumizing treatment, then the quartz tube is sealed, and finally the sealed quartz tube is subjected to vacuum heat treatment.

[0028] In the present application, the quartz tube is preferably a cleaned and dried quartz tube. The present application does not have special limitations on the specific operation of cleaning and drying, and the impurities inside the quartz tube can be removed. As an embodiment of the present application, the operation of cleaning and drying can be soaking the quartz tube in aqua regia for 10-12 hours, then washing with distilled water, and finally drying in a drying oven.

[0029] In the present application, the heating is preferably external heating, the temperature of the heating is preferably 80-100°C, and the time of the heating is preferably 2-3 hours. The present application can remove residual water vapor by heating.

[0030] The present application preferably uses a vacuumizing device for vacuumizing treatment. The present application does not have special limitations on the specific model and source of the vacuumizing device, and commercially available vacuumizing devices known to those skilled in the art can be used as long as the vacuum degree inside the quartz tube meets the requirements. In the present application, the time of the vacuumizing treatment is preferably 3-4 hours, and the vacuumizing treatment is preferably to make the vacuum degree inside the quartz tube <10 -4 Pa.

[0031] The present application does not have special limitations on the specific operation of sealing the quartz tube, and the operation of sealing the quartz tube known to those skilled in the art can be used as long as the quartz tube is completely closed and the vacuum degree inside meets the requirements.

[0032] In the present application, the vacuum heat treatment is preferably carried out in a resistance heating swing melting furnace. The present application does not have special limitations on the specific model and source of the resistance heating swing melting furnace, and commercially available resistance heating swing melting furnaces known to those skilled in the art can be used.

[0033] In the present application, the holding temperature of the vacuum heat treatment is preferably 600-750℃; the time of the vacuum heat treatment is preferably 10-20h; the vacuum degree of the vacuum heat treatment is preferably <10 -4 Pa; the heating rate for heating to the holding temperature of the vacuum heat treatment is preferably 60-120℃ / h; the cooling mode of the vacuum heat treatment is preferably first cooling at a cooling rate of 50-120℃ / h to 250-450℃, standing for 20-60min, and then fast cooling to room temperature; the fast cooling mode is preferably water cooling or quenching with a high-pressure air gun. Through the vacuum heat treatment, the raw material can be melted at high temperature to form a chalcogenide glass.

[0034] As an embodiment of the present application, the holding temperature of the vacuum heat treatment can be 650-700℃; the time of the vacuum heat treatment can be 12h, 14h, 15h, 16h or 18h; the heating rate for heating to the holding temperature of the vacuum heat treatment can be 70℃ / h, 80℃ / h, 90℃ / h, 100℃ / h or 110℃ / h; the cooling mode of the vacuum heat treatment can be first cooling at a cooling rate of 60-100℃ / h to 300-400℃, standing for 30-50min, and then fast cooling to room temperature, or first cooling at a cooling rate of 80-90℃ / h to 350-400℃, standing for 40min, and then fast cooling to room temperature.

[0035] After obtaining the chalcogenide glass, the chalcogenide glass is subjected to annealing treatment to obtain a chalcogenide glass with a negative refractive index temperature coefficient.

[0036] In the present application, the annealing treatment is preferably carried out in an annealing furnace. The present application does not have special limitations on the specific model and source of the annealing furnace, and a commercially available annealing furnace known to those skilled in the art can be used.

[0037] In the present application, the temperature of the annealing treatment is preferably 5-20℃ lower than the transition temperature of the chalcogenide glass; the holding time of the annealing treatment is preferably 3-10h; and the cooling rate of the annealing treatment is preferably 5-10℃ / h. Through the annealing treatment, on the one hand, the thermal stress of the chalcogenide glass caused by intense and uneven temperature changes during production can be eliminated, and on the other hand, the internal structure of the glass product can be stabilized, and the optical performance of the chalcogenide glass can be improved; in addition, through the annealing treatment, the strength of the chalcogenide glass can be improved, and its brittleness can be reduced, making it more durable.

[0038] As an embodiment of the present application, the temperature of the annealing treatment can be 10-15℃ lower than the transition temperature of the chalcogenide glass; the holding time of the annealing treatment can be 4h, 5h, 6h, 7h, 8h or 9h; and the cooling rate of the annealing treatment can be 6-9℃ / h, or 7-8℃ / h.

[0039] The present application prepares infrared chalcogenide glass with optical uniformity by adopting high-temperature melting, rapid cooling and annealing to eliminate internal stress, which is not only simple in preparation method, but also enables the dn / dT value of the chalcogenide glass to be -45 to -19 ppm / K.

[0040] The present application also provides application of the chalcogenide glass with negative refractive index temperature coefficient in the technical solution or the chalcogenide glass prepared by the preparation method in military and civilian fields.

[0041] In the present application, the military and civilian fields preferably include the fields of infrared homing head systems, driving assistance systems, fire control, biological medicine and industrial detection.

[0042] The technical solutions in the present application will be clearly and completely described below in combination with the embodiments in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0043] Embodiment 1

[0044] A chalcogenide glass with negative refractive index temperature coefficient, the chemical formula of the chalcogenide glass is As 28 Se 72 ;

[0045] The preparation method of the chalcogenide glass with negative refractive index temperature coefficient is as follows:

[0046] (1) A quartz tube with a diameter of 30 mm is prepared, soaked in aqua regia for 12 h, then washed with distilled water, and then dried in a drying oven for standby, the raw materials As and Se are placed in the washed and dried quartz tube according to the chemical formula, then the quartz tube is connected to a vacuum pumping device for vacuum treatment, the vacuum degree inside the quartz tube is <10 -4 Pa, at the same time, the outside of the quartz tube is heated, the heating temperature is 100℃, the heating time is 2h, then the quartz tube is sealed, finally the sealed quartz tube is placed in a resistance heating type swing melting furnace, first heated to 750℃ at a heating rate of 100℃ / h for vacuum heat treatment for 15h, then cooled to 280℃ at a cooling rate of 100℃ / h, and then water-cooled to room temperature after standing for 30 min to obtain a chalcogenide glass;

[0047] (2) The chalcogenide glass obtained in the step (1) is heated to 100℃ in an annealing furnace for annealing treatment for 5h, and then cooled to room temperature at a cooling rate of 10℃ / h to obtain a chalcogenide glass with negative refractive index temperature coefficient.

[0048] The chalcogenide glass with negative refractive index temperature coefficient prepared in Example 1 is subjected to slicing test, at 10 μm, the refractive index of the chalcogenide glass is 2.61, the dn / dT value of the chalcogenide glass is about -42.6 ppm / K, the density of the chalcogenide glass is 4.9 g / cm 3 , and the glass transition temperature of the chalcogenide glass is 115 ℃.

[0049] Example 2

[0050] A chalcogenide glass with negative refractive index temperature coefficient, the chemical formula of the chalcogenide glass is As 30 Se 70 ;

[0051] The preparation method of the chalcogenide glass with negative refractive index temperature coefficient is as follows:

[0052] (1) A quartz tube with a diameter of 30 mm is prepared, after being soaked in aqua regia for 12 h, the quartz tube is taken out, washed with distilled water, and then dried in a drying oven for standby, raw materials As and Se are put into the washed and dried quartz tube according to the chemical formula, and then the quartz tube is connected to a vacuumizing device for vacuumizing treatment, so that the vacuum degree inside the quartz tube is <10 -4 Pa, at the same time, the outside of the quartz tube is heated, the heating temperature is 100 ℃, and the heating time is 2 h, then the quartz tube is fusion sealed, and finally the fusion sealed quartz tube is placed in a resistance heating type swing melting furnace, first heated to 750 ℃ at a temperature rising rate of 100 ℃ / h for vacuum heat treatment for 15 h, then cooled to 300 ℃ at a temperature falling rate of 100 ℃ / h, and then water-cooled to room temperature after standing for 30 min to obtain a chalcogenide glass;

[0053] (2) The chalcogenide glass obtained in the step (1) is heated to 120 ℃ in an annealing furnace for annealing treatment for 5 h, and then cooled to room temperature at a cooling rate of 10 ℃ / h to obtain a chalcogenide glass with negative refractive index temperature coefficient.

[0054] The chalcogenide glass with negative refractive index temperature coefficient prepared in Example 2 is subjected to slicing test, at 10 μm, the refractive index of the chalcogenide glass is 2.66, the dn / dT value of the chalcogenide glass is about -21.0 ppm / K, the density of the chalcogenide glass is 4.52 g / cm 3 , and the glass transition temperature of the chalcogenide glass is 126 ℃.

[0055] The refractive index and dn / dT value of the chalcogenide glass provided in Examples 1-2 are shown in Table 1.

[0056] Table 1 Refractive index and dn / dT value of chalcogenide glass provided in Examples 1-2

[0057]

[0058] As can be seen from Table 1, the dn / dT value of the chalcogenide glass prepared by the present application is -45 to -19 ppm / K, and the refractive index is 2.604 to 2.68. Thus, it can be seen that the chalcogenide glass prepared by the present application can effectively compensate the refractive index change with temperature characteristics of conventional lenses, and reduce or even eliminate the thermal effect. As can be seen from the comparison of the refractive index and dn / dT value of the chalcogenide glass provided by Example 1 and Example 2, when the content of As in the chalcogenide glass is adjusted in the range of 20 to 36%, the dn / dT value of the chalcogenide glass can be controlled, so that corresponding adjustment can be made according to the requirements of the chalcogenide glass. It can also be seen that the refractive index of the chalcogenide glass decreases with the increase of wavelength, and as can be seen from the comparison of Example 1 and 2, the linear refractive index value of the chalcogenide glass decreases with the increase of the dn / dT value, which shows that the chalcogenide glass provided by the present application can be used as a passive athermalization lens element in an infrared system, and is of great significance to the athermalization of the system.

[0059] The above only describes the preferred embodiments of the present application, and it should be noted that those skilled in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A chalcogenide glass with a negative refractive index temperature coefficient, wherein the chemical formula of the chalcogenide glass is As. x Se 100-x ,in, x ranges from 20 to 36.

2. The chalcogenide glass according to claim 1, characterized in that, The value of x is 25 to 35.

3. The chalcogenide glass according to claim 1, characterized in that, The chalcogenide glass further includes additive elements; the additive elements include one or more of Ga, Ge, Sn, Sb, S and Te.

4. A method for preparing chalcogenide glass with a negative refractive index temperature coefficient as described in any one of claims 1 to 3, comprising the following steps: (1) The raw materials of chalcogenide glass are subjected to vacuum heat treatment to obtain chalcogenide glass; (2) Anneal the chalcogenide glass obtained in step (1) to obtain chalcogenide glass with negative refractive index temperature coefficient.

5. The preparation method according to claim 4, characterized in that, In step (1), the holding temperature for vacuum heat treatment is 600–750°C, the vacuum heat treatment time is 10–20 hours, and the vacuum degree of vacuum heat treatment is <10. -4 Pa.

6. The preparation method according to claim 5, characterized in that, The heating rate in step (1) to the vacuum heat treatment holding temperature is 60-120℃ / h.

7. The preparation method according to claim 5, characterized in that, The cooling method for vacuum heat treatment in step (1) is to first cool down to 250-450°C at a cooling rate of 50-120°C / h, let it stand for 20-60 minutes, and then quickly cool it to room temperature; the quick cooling method is water cooling or quenching with a high-pressure air gun.

8. The preparation method according to claim 4, characterized in that, In step (2), the annealing temperature is 5-20°C lower than the chalcogenide glass transition temperature, the holding time of the annealing is 3-10h, and the cooling rate of the annealing is 5-10°C / h.

9. The application of the chalcogenide glass with negative refractive index temperature coefficient according to any one of claims 1 to 3 or the chalcogenide glass with negative refractive index temperature coefficient prepared by the preparation method according to any one of claims 4 to 8 in military and civilian fields.

10. The application according to claim 9, characterized in that, The military and civilian applications include infrared seeker systems, driver assistance systems, fire monitoring, biomedical applications, and industrial inspection.

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