Application of biguanide carbonate or biguanide nitrate as nonlinear optical crystal

Abstract

The present application relates to the application of biguanide carbonate or biguanide nitrate as a nonlinear optical crystal, specifically, using biguanide carbonate or biguanide nitrate as a nonlinear optical crystal to achieve ultraviolet frequency-doubled laser output. According to experimental tests, the frequency-doubled effect of biguanide nitrate powder is about 3.5×KDP, and the ultraviolet cutoff edge is about 318nm; the frequency-doubled effect of biguanide carbonate powder is about 5×KDP, and the ultraviolet cutoff edge is about 258nm. Compared with the frequency-doubled effect of guanidine phosphate of 1.5×KDP, the second-order nonlinear optical performance of biguanide carbonate and biguanide nitrate has been greatly improved; these two crystals are stable in the air, with high product purity, and compared with the layered growth habit of potassium fluoroborate berylliumate crystals, they have a fast growth rate and are easy to grow large-sized transparent single crystals, which can be used as ultraviolet and ultraviolet solar-blind nonlinear optical crystals in all-solid-state lasers.

Description

Technical Field

[0001] The present application relates to the application field of biguanide carbonate or biguanide nitrate, and in particular to the application of biguanide carbonate or biguanide nitrate as nonlinear optical crystals. Background Art

[0002] Nonlinear optical materials are materials that show more than secondary nonlinear optical effects in response to strong laser electric fields. Among optical materials, nonlinear optical materials, as the core components of all-solid-state lasers, refer to crystals that use their second-order nonlinear optical effects to expand the wavelength range of lasers and achieve frequency conversion, and play an extremely important role in the laser field. The requirement for this crystal material must be a non-centrosymmetric crystal, which is often used in laser frequency doubling, difference frequency, sum frequency, and multiple frequency doubling. Since potassium dihydrogen phosphate KDP has excellent nonlinear optical properties, a large nonlinear optical coefficient, and can achieve phase matching, it is widely used to make various laser frequency doubling materials. Potassium fluoroborate beryllium crystal KBBF is the only nonlinear optical crystal that can achieve laser output in the deep ultraviolet band. However, the compound contains highly toxic beryllium, and the KBBF crystal has a serious layered growth habit, which seriously restricts the production and application of KBBF crystals. Guanidine phosphate [C(NH2)3]3PO4·2H2O is a new type of metal-free ultraviolet phosphate nonlinear optical crystal. Due to [PO4] 3− Phosphates have smaller microscopic second-order polarizability and polarization anisotropy, which often leads to smaller frequency doubling effect and birefringence. Summary of the invention

[0003] The object of the present invention is to provide an application of biguanide carbonate or biguanide nitrate as a nonlinear optical crystal, which can achieve moderate birefringence and a large second harmonic generation response SHG for phase matching PM in a desired wavelength range and obtain high laser conversion efficiency.

[0004] The technical solution adopted by the present invention is: an application of biguanide carbonate or biguanide nitrate, specifically using biguanide carbonate or biguanide nitrate as a nonlinear optical crystal to achieve ultraviolet frequency-doubled laser output;

[0005] The chemical formula of biguanide carbonate nonlinear optical crystal is (C2N5H8)2CO3, the molecular weight is 264.28, it belongs to the monoclinic system, and the space group is P 21, the unit cell parameters are a=7.0711(6) Å, b=9.3735(5) Å, c=9.4706(6) Å, V=591.69Å 3 , Z = 2;

[0006] The chemical formula of biguanide nitrate nonlinear optical crystal is (C2N5H9)(NO3)2, the molecular weight is 227.16, it belongs to the orthorhombic system, and the space group is P ca21, unit cell parameters are a=14.0566(6) Å, b=6.9300(3) Å, c=9.0084(3) Å, V=877.53 Å 3 , Z=4.

[0007] Furthermore, when biguanide carbonate or biguanide nitrate is used as a nonlinear optical crystal, it participates in the construction of a nonlinear optical device.

[0008] Furthermore, the nonlinear optical device comprises an all-solid-state laser, wherein a laser, a fully converging lens, a biguanide carbonate nonlinear optical crystal or a biguanide nitrate nonlinear optical crystal, a beam splitter prism and a filter are sequentially arranged along the optical path.

[0009] Furthermore, the method for preparing the biguanide carbonate nonlinear optical crystal comprises the following steps:

[0010] Mix C2H8ClN5 and Ag2CO3 in a molar ratio of 3:2 and dissolve them in 10 ml of distilled water;

[0011] b The solution obtained in step a was stirred for ten minutes, a precipitate was formed at the bottom, the precipitate was filtered and stirred for five minutes until the solution was clear;

[0012] c. Seal with weighing paper or plastic wrap, poke small holes in the weighing paper or plastic wrap, and leave at room temperature for 6 to 15 days;

[0013] d. Colorless and transparent block crystals grow at the bottom of the solution, which are (C2N5H8)2CO3 nonlinear optical crystals.

[0014] Furthermore, the method for preparing the biguanide nitrate nonlinear optical crystal comprises the following steps:

[0015] a. Dissolve C2H8ClN5, AgNO3, and HNO3 in 4 ml of distilled water at a molar ratio of 1:2:5;

[0016] b The solution obtained in step a was stirred for ten minutes, a precipitate was formed at the bottom, the precipitate was filtered and stirred for five minutes until the solution was clear;

[0017] c. Seal with weighing paper or plastic wrap, poke small holes in the weighing paper or plastic wrap, and leave at room temperature for 6-15 days;

[0018] d. Colorless and transparent block crystals grow at the bottom of the solution, which are (C2N5H9)(NO3)2 nonlinear optical crystals.

[0019] The beneficial effects of the present invention are as follows: the frequency doubling effect of (C2N5H9)(NO3)2 powder is about 3.5×KDP, and the ultraviolet cutoff edge is about 318nm; the frequency doubling effect of (C2N5H8)2CO3 powder is about 5×KDP, and the ultraviolet cutoff edge is about 258nm. Compared with the frequency doubling effect of guanidine phosphate [C(NH2)3]3PO4·2H2O of 1.5×KDP, the second-order nonlinear optical performance of biguanide carbonate and biguanide nitrate is greatly improved; these two crystals are stable in the air, and the product purity is high. Compared with the layered growth habit of potassium fluoroborate berylliumate crystal KBBF, the growth rate is fast, and it is easy to grow large-sized transparent single crystals, which can be used as ultraviolet and ultraviolet solar-blind nonlinear optical crystals in all-solid-state lasers. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 A working principle diagram of a typical nonlinear optical device made of (C2N5H8)2CO3 nonlinear optical crystal or (C2N5H9)(NO3)2 nonlinear optical crystal;

[0022] Figure 2 is an X-ray powder diffraction pattern of the (C2N5H8)2CO3 nonlinear optical crystal in an embodiment of the present invention;

[0023] Figure 3 is an X-ray powder diffraction pattern of the (C2N5H9)(NO3)2 nonlinear optical crystal in an embodiment of the present invention;

[0024] Figure 4 2 is a crystal structure diagram of the (C2N5H8)2CO3 nonlinear optical crystal in an embodiment of the present invention;

[0025] Figure 5 2 is a crystal structure diagram of the (C2N5H9)(NO3)2 nonlinear optical crystal in an embodiment of the present invention;

[0026] Figure 6 is the ultraviolet transmission spectrum of the (C2N5H8)2CO3 nonlinear optical crystal in the embodiment of the present invention;

[0027] Figure 7 is the ultraviolet transmission spectrum of the (C2N5H9)(NO3)2 nonlinear optical crystal in the embodiment of the present invention;

[0028] Figure 8 It is a second harmonic signal diagram of the (C2N5H8)2CO3 nonlinear optical crystal and the standard sample in the embodiment of the present invention, that is, the potassium dihydrogen phosphate KDP crystal size is in the range of 105 to 150 μm;

[0029] Fig. 9 It is a second harmonic signal diagram of the (C2N5H9)(NO3)2 nonlinear optical crystal and the standard sample in the embodiment of the present invention, that is, the potassium dihydrogen phosphate KDP crystal size is in the range of 105 to 150 μm;

[0030] Fig.10 This is a second harmonic phase matching diagram of the (C2N5H8)2CO3 nonlinear optical crystal in the 1064nm band in an embodiment of the present invention;

[0031] Fig.11 This is the second harmonic phase matching diagram of the (C2N5H9)(NO3)2 nonlinear optical crystal in the 1064nm band in an embodiment of the present invention.

[0032] Explanation of reference numerals: 1 - laser, 2 - condenser lens, 3 - nonlinear optical crystal, 4 - beam splitter prism, 5 - filter. DETAILED DESCRIPTION

[0033] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention can also be implemented in other ways different from those described herein, and therefore, the present invention is not limited to the limitations of the specific embodiments disclosed below.

[0034] The embodiment of the present invention provides an application of biguanide carbonate or biguanide nitrate, specifically using biguanide carbonate or biguanide nitrate as a nonlinear optical crystal to achieve ultraviolet frequency-doubled laser output.

[0035] In the embodiment of the present invention, biguanide carbonate or biguanide nitrate, when used as a nonlinear optical crystal, participates in forming a nonlinear optical device. The nonlinear optical device includes an all-solid-state laser, and the specific structure of the all-solid-state laser is as follows: Figure 1 As shown, a laser 1, a condenser lens 2, a nonlinear optical crystal 3, a beam splitter prism 4 and a filter 5 are sequentially arranged along the optical path. Figure 1 In the figure, a beam is emitted from a laser 1, which is incident on a nonlinear optical crystal 3 made of (C2N5H9)(NO3)2 or (C2N5H8)2CO3 through a condenser lens 2. The output beam is then passed through a beam splitter prism 4 and a filter 5 to obtain the desired laser beam. ω represents the frequency of the refracted light, which is equal to or twice the frequency of the incident light.

[0036] The chemical formula of biguanide carbonate nonlinear optical crystal is (C2N5H8)2CO3, the molecular weight is 264.28, it belongs to the monoclinic system, and the space group is P 21, the unit cell parameters are a=7.0711(6) Å, b=9.3735(5) Å, c=9.4706(6) Å, V=591.69Å 3 , Z=2, the crystal structure is as follows Figure 4 The embodiment of the present invention adopts the aqueous solution method to prepare (C2N5H8)2CO3 crystals, and the reaction equation is as follows:

[0037] 2C2H8ClN5+ Ag2CO3 = (C2N5H8)2CO3+ 2AgCl↓

[0038] The amounts of the two reactants used in the preparation process are: 3 mmol C2H8ClN50.417 grams, 2 mmol Ag2CO30.553 grams, and the specific preparation method is as follows:

[0039] a. Dissolve C2H8ClN5 and Ag2CO3 in 10 ml of distilled water at a molar ratio of 3:2;

[0040] b The solution obtained in step a was stirred for ten minutes, a precipitate was formed at the bottom, the precipitate was filtered and stirred for five minutes until the solution was clear;

[0041] c. Seal with weighing paper or plastic wrap, poke small holes in the weighing paper or plastic wrap, and leave at room temperature for 6 to 15 days;

[0042] d. Colorless and transparent block crystals grow at the bottom of the solution, which are (C2N5H8)2CO3 nonlinear optical crystals.

[0043] The chemical formula of biguanide nitrate nonlinear optical crystal is (C2N5H9)(NO3)2, the molecular weight is 227.16, it belongs to the orthorhombic system, and the space group is P ca21, unit cell parameters are a=14.0566(6) Å, b=6.9300(3) Å, c=9.0084(3) Å, V=877.53 Å 3 , Z=4, the crystal structure is as follows Figure 5 The embodiment of the present invention adopts a hydrothermal reaction method to prepare (C2N5H8)2CO3 crystals, and the reaction equation is as follows:

[0044] C2H8ClN5+ AgNO3+ HNO3 = (C2N5H9)(NO3)2+ AgCl↓

[0045] The amounts of the three reactants used in the preparation process are: 1 mmol C2H8ClN50.139 grams, 2 mmol AgNO30.338 grams and 5 mmol HNO30.3mL. The specific preparation method is as follows:

[0046] a. Dissolve C2H8ClN5, AgNO3, and HNO3 in 4 ml of distilled water at a molar ratio of 1:2:5;

[0047] b The solution obtained in step a was stirred for ten minutes, a precipitate was formed at the bottom, the precipitate was filtered and stirred for five minutes until the solution was clear;

[0048] c. Seal with weighing paper or plastic wrap, poke small holes in the weighing paper or plastic wrap, and leave at room temperature for 6-15 days;

[0049] d. Colorless and transparent block crystals grow at the bottom of the solution, which are (C2N5H9)(NO3)2 nonlinear optical crystals.

[0050] Compared with potassium fluoroborate beryllium crystal KBBF, the agents and raw materials used in the preparation process of (C2N5H9)(NO3)2 nonlinear optical crystal or (C2N5H8)2CO3 nonlinear optical crystal are less toxic to the human body, have a short growth cycle, low cost, and are easy to obtain large single crystals; the prepared (C2N5H9)(NO3)2 nonlinear optical crystal or (C2N5H8)2CO3 nonlinear optical crystal has the advantages of shorter ultraviolet absorption cutoff edge, larger nonlinear optical performance and larger birefringence, not easy to deliquesce and break, easy to process and preserve, etc.

[0051] The X-ray diffraction patterns of the prepared (C2N5H8)2CO3 crystalline powder and (C2N5H9)(NO3)2 crystalline powder obtained by experiment are as follows: Figure 2 and Figure 3 As shown in the figure, the black spectrum is the experimental value, and the red spectrum is the simulation value. It can be seen from the figure that the prepared (C2N5H8)2CO3 crystal powder and (C2N5H9)(NO3)2 crystal powder are consistent with the spectra obtained by fitting their single crystal structures.

[0052] The transmission spectrum of (C2N5H8)2CO3 nonlinear optical crystal and (C2N5H9)(NO3)2 nonlinear optical crystal was tested. Figure 6 As shown in the experiment, the ultraviolet absorption cutoff edge of the (C2N5H8)2CO3 nonlinear optical crystal is about 258 nm. Figure 7 As shown, the experimentally measured ultraviolet absorption cutoff edge of the (C2N5H9)(NO3)2 nonlinear optical crystal is approximately 318 nm.

[0053] The frequency doubling test experiment of (C2N5H8)2CO3 nonlinear optical crystal and (C2N5H9)(NO3)2 nonlinear optical crystal is as follows: The (C2N5H8)2CO3 nonlinear optical crystal is used to form Figure 1 The nonlinear optical device shown in the figure uses the 1064nm output of a Q-switched Nd:YAG laser as the light source at room temperature, and an obvious 532nm doubled frequency green light output is observed, as shown in FIG. Figure 8 As shown, the output intensity is about 5 times that of potassium dihydrogen phosphate crystal KDP under the same conditions; the (C2N5H9)(NO3)2 nonlinear optical crystal is used to form Figure 1 The nonlinear optical device shown in the figure uses the 1064nm output of a Q-switched Nd:YAG laser as the light source at room temperature, and an obvious 532nm doubled frequency green light output is observed, as shown in FIG. Fig. 9 As shown, the output intensity is about 3.5 times that of potassium dihydrogen phosphate crystal KDP under the same conditions.

[0054] The (C2N5H8)2CO3 crystal sample, (C2N5H9)(NO3)2 crystal sample and the standard sample, namely potassium dihydrogen phosphate crystal KDP, were ground separately and sieved out with a standard sieve to obtain crystals of different particle sizes, with the particle size ranges being less than 35μm, 35μm to 50μm, 50μm to 70μm, 70μm to 100μm, 100μm to 140μm and 140 to 200μm. The variation trend of the frequency-doubled signal with the particle size was observed to determine whether phase matching could be achieved. The second harmonic phase matching diagram of the (C2N5H8)2CO3 nonlinear optical crystal is shown in Figure 2. Fig.10 As shown in the figure, the second harmonic phase matching diagram of (C2N5H9)(NO3)2 nonlinear optical crystal is as follows Fig.11 As shown in the figure, it can be seen that both crystal materials can achieve phase matching in the 1064nm band.

[0055] The birefringence of (C2N5H8)2CO3 nonlinear optical crystal and (C2N5H9)(NO3)2 nonlinear optical crystal was tested at 550 nm using a polarizing microscope. The birefringence of (C2N5H8)2CO3 nonlinear optical crystal was 0.232@550 nm, and the birefringence of (C2N5H9)(NO3)2 nonlinear optical crystal was 0.123@550 nm. Compared with the birefringence of guanidine phosphate, which is 0.055@546.1 nm, (C2N5H8)2CO3 nonlinear optical crystal and (C2N5H9)(NO3)2 nonlinear optical crystal show larger birefringence.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. The use of biguanide carbonate or biguanide nitrate, characterized in that: Using biguanide carbonate or biguanide nitrate as nonlinear optical crystal to achieve ultraviolet frequency-doubled laser output; The chemical formula of biguanide carbonate nonlinear optical crystal is (C2N5H8)2CO3, the molecular weight is 264.28, it belongs to the monoclinic system, and the space group is P 21, the unit cell parameters are a=7.0711(6) Å, b=9.3735(5) Å, c=9.4706(6) Å, V=591.69 Å 3 , Z=2; The chemical formula of biguanide nitrate nonlinear optical crystal is (C2N5H9)(NO3)2, the molecular weight is 227.16, it belongs to the orthorhombic system, and the space group is P ca21, unit cell parameters are a=14.0566(6) Å, b=6.9300(3) Å, c=9.0084(3) Å, V=877.53Å 3 , Z=4.

2. The use of biguanide carbonate or biguanide nitrate according to claim 1, characterized in that: When biguanide carbonate or biguanide nitrate is used as a nonlinear optical crystal, it participates in forming a nonlinear optical device.

3. The use of biguanide carbonate or biguanide nitrate according to claim 2, characterized in that: The nonlinear optical device comprises an all-solid-state laser, wherein a laser, a fully converging lens, a biguanide carbonate nonlinear optical crystal or a biguanide nitrate nonlinear optical crystal, a beam splitter prism and a filter are sequentially arranged along the optical path direction.

4. The use of biguanide carbonate or biguanide nitrate according to claim 1, characterized in that: The preparation method of the biguanide carbonate nonlinear optical crystal comprises the following steps: a. Dissolve C2H8ClN5 and Ag2CO3 in 10 ml of distilled water at a molar ratio of 3:2; b The solution obtained in step a was stirred for ten minutes, a precipitate was formed at the bottom, the precipitate was filtered and stirred for five minutes until the solution was clear; c. Seal with weighing paper or plastic wrap, poke small holes in the weighing paper or plastic wrap, and leave at room temperature for 6 to 15 days; d. Colorless and transparent block crystals grow at the bottom of the solution, which are (C2N5H8)2CO3 nonlinear optical crystals.

5. The use of biguanide carbonate or biguanide nitrate according to claim 1, characterized in that: The preparation method of the biguanide nitrate nonlinear optical crystal comprises the following steps: Mix and dissolve C2H8ClN5, AgNO3, and HNO3 in 4 ml of distilled water at a molar ratio of 1:2:5; b The solution obtained in step a was stirred for ten minutes, a precipitate was formed at the bottom, the precipitate was filtered and stirred for five minutes until the solution was clear; c. Seal with weighing paper or plastic wrap, poke small holes in the weighing paper or plastic wrap, and leave at room temperature for 6-15 days; d. Colorless and transparent block crystals grow at the bottom of the solution, which are (C2N5H9)(NO3)2 nonlinear optical crystals.

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