Femtosecond pulse laser irradiation device and seed cultivation method

Abstract

The invention discloses a femtosecond pulse laser irradiation device and a seed cultivation method, and relates to the technical field of laser. The irradiation device comprises a femtosecond laser light source module, a multiband optical filter, a dispersion compensator, a flat-top light beam expanding system and an objective table; the femtosecond laser light source module comprises a femtosecond laser source, a coupling system, a zero dispersion photonic crystal fiber, a bridging fiber and a zero dispersion fiber; the coupling system is used for coupling laser output by the femtosecond laser source into the optical fiber; the zero-dispersion photonic crystal fiber and the zero-dispersion optical fiber are high-nonlinearity photonic crystal fibers; the surface of the multi-band optical filter is plated with a multi-band high-transmittance film and a high-reflection film system; the dispersion compensator is used for compensating the laser dispersion amount; the flat-topped light beam expanding system is used for changing the Gaussian beam into flat-topped light and expanding the flat-topped light; the objective table is used for containing seeds to be cultivated. The device is utilized to irradiate seeds and cultivate the seeds, the seed vitality can be improved, the effects of cold resistance, drought resistance, lodging resistance and the like of plants are promoted, and the cultivation efficiency of good varieties of crops is improved.

Description

Technical Field

[0001] The present invention relates to the field of laser technology, and in particular to a femtosecond pulse laser irradiation device and a seed cultivation method. Background Art

[0002] At present, there are many methods of irradiation breeding, the most typical of which are cobalt source radiation breeding and laser breeding. Among them, the cobalt source radiation breeding method has a short radiation wavelength and high energy, which causes greater damage to seeds and the effect is not very ideal; the energy controllable effect of the laser irradiation breeding method is more ideal, but the laser light source wavelength of traditional laser irradiation breeding is relatively single and cannot adapt to the needs of various environments, especially cannot meet the various needs of drought resistance, lodging resistance, and early maturity and yield increase. Summary of the Invention

[0003] In view of the above problems, the present invention proposes a femtosecond pulse laser irradiation device and a seed cultivation method in an effort to solve or alleviate one or more of the above problems.

[0004] According to one aspect of the present invention, a femtosecond pulse laser irradiation device is provided, comprising: a femtosecond laser light source module 1, a multi-band filter 2, a dispersion compensator 3, a flat-top beam expansion system 4, and a stage 5; the central axes of the femtosecond laser light source 1, the multi-band filter 2, the dispersion compensator 3, and the flat-top beam expansion system 4 are aligned horizontally;

[0005] The femtosecond laser light source module 1 includes a femtosecond laser source 11, a coupling system 12, a zero-dispersion photonic crystal fiber 13, a bridge fiber 14, and a zero-dispersion fiber 15; the coupling system 12 is used to couple the laser output by the femtosecond laser source 11 into the optical fiber; the zero-dispersion photonic crystal fiber 13 and the zero-dispersion fiber 15 are highly nonlinear photonic crystal fibers;

[0006] The surface of the multi-band filter 2 is coated with a multi-band high-transmittance film and a high-reflection film system;

[0007] The dispersion compensator 3 is used to compensate for the dispersion of the laser light after being filtered by the multi-band filter 2;

[0008] The flat-top beam expansion system 4 is used to convert the Gaussian beam filtered by the dispersion compensator 3 into a flat-top beam and expand the beam for output;

[0009] The loading platform 5 is used for holding seeds to be cultivated.

[0010] Furthermore, the laser wavelength range output by the femtosecond laser light source module 1 is 300nm-2400nm.

[0011] Furthermore, the femtosecond laser source 11 outputs a laser with a central wavelength of 1030 nm, a laser repetition frequency of 20 MHz, a pulse width of 150 fs, and a maximum average output power of 8.5 W.

[0012] Furthermore, the zero-dispersion photonic crystal fiber 13 is a highly nonlinear photonic crystal fiber with a zero-dispersion point of 700-900 nm; and the zero-dispersion fiber 15 is a highly nonlinear photonic crystal fiber with a zero-dispersion point of 1040 nm.

[0013] Furthermore, the bridge optical fiber 14 is a single-mode optical fiber.

[0014] Furthermore, the flat-top beam expansion system 4 includes a deformable mirror and a beam expansion subsystem. The deformable mirror is used to transform the Gaussian beam into a flat-top beam, and the beam expansion subsystem is used to further expand the flat-top beam spot.

[0015] Furthermore, the surface of the multi-band filter 2 is coated with high-transmittance films of 300-320nm, 380-420nm, 620-650nm, 900-1030nm, 1550-1700nm and 1900-2200nm and high-reflection films of other bands.

[0016] Furthermore, the loading platform 5 includes: two slides 51, a loading platform 54 including an upper flat circular steel plate 52 and a lower flat circular steel plate 53, two grooves 55, and a fixing lock 56; the loading platform 54 is embedded and fixed in the middle of the two slides 51 through the two grooves 55; the upper flat circular steel plate 52 and the lower flat circular steel plate 53 are respectively on the upper and lower sides of the loading platform 54, and can be fixed in the middle of the two slides 51 through the fixing lock 56.

[0017] According to another aspect of the present invention, a seed cultivation method is provided. The method is implemented based on the femtosecond pulse laser irradiation device described above. The method comprises:

[0018] Fix the fixing lock 56 of the lower flat circular steel plate 53, remove the upper flat circular steel plate 52, place the seeds to be cultivated on the lower flat circular steel plate 53, and use the femtosecond pulse laser irradiation device to irradiate the seeds with the expanded flat top light according to the irradiation time corresponding to the seed type;

[0019] Put the upper flat circular steel plate 52 back onto the stage 5 and move it downward continuously until it is in full contact with the seeds, and fix the fixing lock 56 of the upper flat circular steel plate 52; flip the stage 54 so that the lower flat circular steel plate 53 is facing upward, remove the lower flat circular steel plate 53, and then use the femtosecond pulse laser irradiation device to irradiate the expanded flat-top light onto the seeds according to the irradiation time corresponding to the seed type.

[0020] Furthermore, the step of using the femtosecond pulse laser irradiation device to irradiate the expanded flat-top light onto the seeds according to the irradiation time corresponding to the seed type includes:

[0021] A femtosecond laser source 11 is coupled by a coupling system 12 and enters a zero-dispersion photonic crystal fiber 13, and then successively enters a bridge fiber 14 and a zero-dispersion fiber 15. The laser emitted by the femtosecond laser source 11 generates first-order, second-order, and third-order nonlinear phenomena in the zero-dispersion photonic crystal fiber 13, the bridge fiber 14, and the zero-dispersion fiber 15, and then outputs a femtosecond pulse laser of 300-2400 nm. The 300-2400 nm femtosecond pulse laser is filtered by a multi-band filter 2, and after filtering, lasers of 300-320 nm, 380-420 nm, 620-650 nm, 900-1030 nm, 1550-1700 nm, and 1900-2200 nm remain. The laser then passes through a dispersion compensator 3 for dispersion compensation, and finally passes through a flat-top beam expansion system 4 for beam expansion output.

[0022] The beneficial technical effects of the present invention are:

[0023] The present invention proposes a femtosecond pulse laser irradiation device and a seed cultivation method. The irradiation device is used to irradiate seeds and cultivate them, which can effectively kill seed epidermal fungi and prevent diseases and insect pests after seed development; promote the development of lush branches and leaves of seeds and early maturity of fruits and strong roots; promote the plant's cold resistance, drought resistance, and lodging resistance; enhance seed vitality and promote its mutation, thereby improving the cultivation efficiency of excellent crop varieties. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above and other objects, features and advantages of the exemplary embodiments of the present invention will become readily apparent by reading the following detailed description with reference to the accompanying drawings, in which several embodiments of the present invention are shown by way of example and not limitation, in which:

[0025] Figure 1 It is a structural schematic diagram of a femtosecond pulse laser irradiation device described in an embodiment of the present invention.

[0026] Figure 2 2 is a schematic structural diagram of the object carrier in an embodiment of the present invention. DETAILED DESCRIPTION

[0027] The principles and spirit of the present invention will be described below with reference to several exemplary embodiments. It should be understood that these embodiments are provided solely to enable those skilled in the art to better understand and implement the present invention, and are not intended to limit the scope of the present invention in any way. Rather, these embodiments are provided to make this disclosure more thorough and complete, and to fully convey the scope of the present disclosure to those skilled in the art.

[0028] The embodiment of the present invention provides a femtosecond pulse laser irradiation device, such as Figure 1 As shown, the device includes: a femtosecond laser light source module 1, a multi-band filter 2, a dispersion compensator 3, a flat-top beam expansion system 4, and a stage 5; the central axes of the femtosecond laser light source 1, the multi-band filter 2, the dispersion compensator 3, and the flat-top beam expansion system 4 are on a horizontal line;

[0029] The femtosecond laser light source module 1 includes a femtosecond laser source 11, a coupling system 12, a zero-dispersion photonic crystal fiber 13, a bridge fiber 14, and a zero-dispersion fiber 15; the coupling system 12 is used to couple the laser output by the femtosecond laser source 11 into the optical fiber; the zero-dispersion photonic crystal fiber 13 and the zero-dispersion fiber 15 are highly nonlinear photonic crystal fibers;

[0030] The surface of the multi-band filter 2 is coated with a multi-band high-transmittance film and a high-reflection film system;

[0031] The dispersion compensator 3 is used to compensate for the dispersion of the laser light after being filtered by the multi-band filter 2;

[0032] The flat-top beam expansion system 4 is used to convert the Gaussian beam filtered by the dispersion compensator 3 into a flat-top beam and expand the beam for output;

[0033] The loading platform 5 is used for holding seeds to be cultivated.

[0034] In this embodiment, preferably, the laser wavelength range output by the femtosecond laser light source module 1 is 300 nm-2400 nm.

[0035] In this embodiment, preferably, the femtosecond laser source 11 outputs a laser with a central wavelength of 1030 nm, a laser repetition frequency of 20 MHz, a pulse width of 150 fs, and a maximum average output power of 8.5 W; the laser is mainly a laser source with zero-dispersion photonic crystal fibers fused at both ends.

[0036] In this embodiment, preferably, the zero-dispersion photonic crystal fiber 13 is a highly nonlinear photonic crystal fiber with a zero dispersion point of 700-900 nm; the zero-dispersion fiber 15 is a highly nonlinear photonic crystal fiber with a zero dispersion point of 1040 nm; and the bridging fiber 14 is a single-mode fiber.

[0037] Specifically, the zero-dispersion photonic crystal fiber 13, the bridge fiber 14, and the zero-dispersion fiber 15 constitute the working material generated by the 300-2400nm femtosecond laser; the zero-dispersion photonic crystal fiber 13 is made of high-purity silica material, the core diameter of the fiber is about 5μm, and its nonlinear coefficient is 18 (W·km) -1This fiber is conducive to the expansion of the supercontinuum spectrum towards the blue end, that is, towards 300nm. The bridge fiber 14 is a single-mode fiber with a numerical aperture of 0.28 and a core diameter of 2.5μm. The fiber is made of high-purity silica. The zero-dispersion fiber 15 is made of high-purity silica. The core diameter of the fiber is about 5μm and the nonlinear coefficient is 11 (W·km). -1 This facilitates spectrum expansion toward the red end, that is, toward 2400 nm. By combining two photonic crystal fibers with significantly different zero-dispersion wavelengths, a supercontinuum spectrum from 300 to 2400 nm is achieved. The zero-dispersion photonic crystal fiber 13, the bridge fiber 14, and the zero-dispersion fiber 15 can be positioned interchangeably.

[0038] In this embodiment, preferably, the coupling system 12 includes a translation stage and a coupling mirror, wherein the translation stage and the coupling mirror are respectively used for parallel movement to find the optimal coupling position, and for coupling the laser emitted by the femtosecond laser source 11 into the zero-dispersion photonic crystal fiber 13.

[0039] In this embodiment, preferably, the surface of the multi-band filter 2 is coated with high-transmittance films of 300-320nm, 380-420nm, 620-650nm, 900-1030nm, 1550-1700nm and 1900-2200nm and high-reflection films of other bands.

[0040] In this embodiment, preferably, the dispersion compensator 3 is used to compensate for the dispersion of the laser after filtering by the multi-band filter 2, so that the width of the compensated laser pulse is consistent with the laser pulse before filtering, which can meet the requirements of the subsequent breeding light source. The dispersion compensator 3 is made of ZnSe material.

[0041] In this embodiment, preferably, the flat-top beam expansion system 4 includes a deformable mirror and a beam expansion subsystem, the deformable mirror is used to transform the Gaussian beam into a flat-top beam, and the beam expansion subsystem is used to further expand the flat-top beam spot.

[0042] In this embodiment, preferably, the loading platform 5 includes: two slides 51, a loading platform 54 including an upper flat circular steel plate 52 and a lower flat circular steel plate 53, two grooves 55, and a fixing lock 56; the loading platform 54 is embedded and fixed in the middle of the two slides 51 through the two grooves 55; the upper flat circular steel plate 52 and the lower flat circular steel plate 53 are respectively on the upper and lower sides of the loading platform 54, and can be fixed in the middle of the two slides 51 through the fixing lock 56.

[0043] Specifically, the bottom of the loading platform 5 is composed of two layers of flat circular steel plates, which can slide on two tracks with upper and lower fixed locks 56 on the side walls of the loading platform 5. The solid locks 56 can fix the flat circular steel plates at any position on the tracks of the loading platform 5. Figure 2 As shown, the loading platform 5 has two slides 51 to ensure that the upper and lower flat circular steel plates 52 and 53 of the loading platform 5 move up and down the loading platform 54. The loading platform 54 is a 300-2400nm high-transmittance CaF2 material. The loading platform 54 is inlaid with two grooves 55 and fixed on the two slides 51; the upper flat circular steel plate 52 and the lower flat circular steel plate 53 can be moved or removed on the two slides 51, and can be fixed on the slide rails with a fixing lock 56. Its main function is to remove the flat circular steel plate when irradiating seeds from the side of the flat circular steel plate, put the flat circular steel plate on and move it to the loading platform 54 to compact the seeds to prevent the seeds from rolling at the end of irradiation with the laser light source, and fix the flat circular steel plate 52 with the fixing lock 56, flip the loading platform 54 so that the upper flat circular steel plate 52 is located below the loading platform 54, remove the lower flat circular steel plate 53 and start irradiating seeds from this side, and the lower flat circular steel plate 53 is fixed with a fixing lock 56.

[0044] Another embodiment of the present invention provides a seed cultivation method, which is implemented based on the femtosecond pulse laser irradiation device described in the above embodiment; the cultivation method includes:

[0045] Fix the fixing lock 56 of the lower flat circular steel plate 53, remove the upper flat circular steel plate 52, place the seeds to be cultivated on the lower flat circular steel plate 53, and use the femtosecond pulse laser irradiation device to irradiate the seeds with the expanded flat top light according to the irradiation time corresponding to the seed type;

[0046] Put the upper flat circular steel plate 52 back onto the stage 5 and move it downward continuously until it is in full contact with the seeds, and fix the fixing lock 56 of the upper flat circular steel plate 52; flip the stage 54 so that the lower flat circular steel plate 53 is facing upward, remove the lower flat circular steel plate 53, and then use the femtosecond pulse laser irradiation device to irradiate the expanded flat-top light onto the seeds according to the irradiation time corresponding to the seed type.

[0047] As an example, the irradiation time corresponding to the seed type is: soybean irradiation time is about 20 seconds; wheat irradiation time is 15 seconds.

[0048] In this embodiment, preferably, the step of using a femtosecond pulse laser irradiation device to irradiate the expanded flat-top light onto the seeds according to the irradiation time corresponding to the seed type includes:

[0049] A femtosecond laser source 11 is coupled by a coupling system 12 and enters a zero-dispersion photonic crystal fiber 13, and then successively enters a bridge fiber 14 and a zero-dispersion fiber 15. The laser emitted by the femtosecond laser source 11 generates first-order, second-order, and third-order nonlinear phenomena in the zero-dispersion photonic crystal fiber 13, the bridge fiber 14, and the zero-dispersion fiber 15, and then outputs a femtosecond pulse laser of 300-2400 nm. The 300-2400 nm femtosecond pulse laser is filtered by a multi-band filter 2, and after filtering, lasers of 300-320 nm, 380-420 nm, 620-650 nm, 900-1030 nm, 1550-1700 nm, and 1900-2200 nm remain. The laser then passes through a dispersion compensator 3 for dispersion compensation, and finally passes through a flat-top beam expansion system 4 for beam expansion output.

[0050] Among them, after filtering, the remaining laser effects of 300-320nm, 380-420nm, 620-650nm, 900-1030nm, 1550-1700nm and 1900-2200nm are as follows: 300-320nm femtosecond laser irradiation of seeds is mainly used to kill fungi on the surface of seeds, 380-420nm femtosecond laser irradiation of seeds is mainly used to prevent diseases and insect pests after seed development, 620-650nm femtosecond laser irradiation of seeds is mainly used to promote the development of lush branches and leaves of seeds and early maturity and strong roots of fruits, 900-1030nm femtosecond laser irradiation of seeds is mainly used to promote the cold resistance of seeds, 1550-1700nm femtosecond laser irradiation of seeds mainly improves the germination rate and seedling growth rate of seeds, and 1900-2200nm femtosecond laser irradiation of seeds is mainly to improve the drought resistance of seeds.

[0051] Although the spirit and principles of the present invention have been described with reference to several specific embodiments, it should be understood that the present invention is not limited to the specific embodiments disclosed, and the division into various aspects does not mean that the features of these aspects cannot be combined to benefit. Such division is only for the convenience of expression. The present invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A femtosecond pulse laser irradiation device, characterized in that: include: A femtosecond laser light source module (1), a multi-band filter (2), a dispersion compensator (3), a flat-top beam expansion system (4), and an object stage (5); the central axes of the femtosecond laser light source (1), the multi-band filter (2), the dispersion compensator (3), and the flat-top beam expansion system (4) are on a horizontal line; The femtosecond laser light source module (1) comprises a femtosecond laser source (11), a coupling system (12), a zero-dispersion photonic crystal fiber (13), a bridging fiber (14) and a zero-dispersion fiber (15); the coupling system (12) is used to couple the laser light output by the femtosecond laser source (11) into the optical fiber; the zero-dispersion photonic crystal fiber (13) and the zero-dispersion optical fiber (15) are highly nonlinear photonic crystal fibers; The surface of the multi-band filter (2) is coated with a multi-band high-transmittance film and a high-reflection film system; The dispersion compensator (3) is used to compensate for the dispersion of the laser light after being filtered by the multi-band filter (2); The flat-top beam expansion system (4) is used to convert the Gaussian beam filtered by the dispersion compensator (3) into a flat-top beam and expand the beam for output; The loading platform (5) is used for holding seeds to be cultivated.

2. A femtosecond pulse laser irradiation device according to claim 1, characterized in that: The laser wavelength output by the femtosecond laser light source module (1) is in the range of 300nm-2400nm.

3. The femtosecond pulse laser irradiation device according to claim 1, characterized in that: The femtosecond laser source (11) outputs a laser with a central wavelength of 1030 nm, a laser repetition frequency of 20 MHz, a pulse width of 150 fs, and a maximum average output power of 8.5 W.

4. The femtosecond pulse laser irradiation device according to claim 1, characterized in that: The zero-dispersion photonic crystal fiber (13) is a high-nonlinear photonic crystal fiber with a zero-dispersion point of 700-900 nm; and the zero-dispersion fiber (15) is a high-nonlinear photonic crystal fiber with a zero-dispersion point of 1040 nm.

5. The femtosecond pulse laser irradiation device according to claim 1, characterized in that: The bridge optical fiber (14) is a single-mode optical fiber.

6. The femtosecond pulse laser irradiation device according to claim 1, characterized in that: The flat-top beam expansion system (4) comprises a deformable mirror and a beam expansion subsystem, wherein the deformable mirror is used to transform a Gaussian beam into a flat-top beam, and the beam expansion subsystem is used to further expand the flat-top beam spot.

7. The femtosecond pulse laser irradiation device according to claim 1, characterized in that: The surface of the multi-band filter (2) is coated with high-transmittance films of 300-320nm, 380-420nm, 620-650nm, 900-1030nm, 1550-1700nm and 1900-2200nm and high-reflection film systems of other bands.

8. The femtosecond pulse laser irradiation device according to claim 1, characterized in that: The loading platform (5) comprises: two slideways (51), a loading platform (54) comprising an upper flat circular steel plate (52) and a lower flat circular steel plate (53), two grooves (55), and a fixing lock (56); the loading platform (54) is embedded and fixed in the middle of the two slideways (51) through the two grooves (55); the upper flat circular steel plate (52) and the lower flat circular steel plate (53) are respectively on the upper and lower sides of the loading platform (54), and can be fixed in the middle of the two slideways (51) through the fixing lock (56).

9. A seed cultivation method, characterized in that: The method is implemented based on a femtosecond pulse laser irradiation device according to any one of claims 1 to 8; the method comprises: Fix the fixing lock (56) of the lower flat circular steel plate (53), remove the upper flat circular steel plate (52), place the seeds to be cultivated on the lower flat circular steel plate (53), and use the femtosecond pulse laser irradiation device to irradiate the seeds with the expanded flat top light according to the irradiation time corresponding to the seed type; The upper flat circular steel plate (52) is placed back on the loading platform (5) and continuously moved downward until it is in full contact with the seeds, and the fixing lock (56) of the upper flat circular steel plate (52) is fixed; the loading platform (54) is turned over to make the lower flat circular steel plate (53) face upward, and the lower flat circular steel plate (53) is removed, and then the flat top light after the beam expansion is irradiated onto the seeds according to the irradiation time corresponding to the seed type using the femtosecond pulse laser irradiation device.

10. A seed cultivation method according to claim 9, characterized in that: The step of using the femtosecond pulse laser irradiation device to irradiate the expanded flat-top light onto the seeds according to the irradiation time corresponding to the seed type includes: A femtosecond laser source (11) is coupled by a coupling system (12) and enters a zero-dispersion photonic crystal fiber (13), and then successively enters a bridge fiber (14) and a zero-dispersion fiber (15). The laser emitted by the femtosecond laser source (11) generates first-order, second-order and third-order nonlinear phenomena in the zero-dispersion photonic crystal fiber (13), the bridge fiber (14) and the zero-dispersion fiber (15), and then outputs a femtosecond pulse laser of 300-2400 nm. The 300-2400 nm femtosecond pulse laser is filtered by a multi-band filter (2), and after filtering, lasers of 300-320 nm, 380-420 nm, 620-650 nm, 900-1030 nm, 1550-1700 nm and 1900-2200 nm remain. The laser is then dispersion compensated by a dispersion compensator (3), and finally expanded and output by a flat-top beam expansion system (4).

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