Method for oscillating multiple laser pulse using multiple q switch and multiple laser pulse oscillator

Abstract

To provide a method for oscillating a multiple laser pulse using a multiple Q switch which can improve the energy efficiency and can reduce the peak power of lasers.SOLUTION: The method for oscillating a multiple laser pulse using a multiple Q switch includes the steps of: forming one cycle of light energy; exciting electrons of a gain medium by the light energy; executing a first Q switch during one cycle of the light energy; oscillating a first laser pulse by the first Q switch; executing a second Q switch during one cycle of the light energy; and oscillating the second laser pulse by the second Q switch.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The technical concept of the present invention relates to a laser generating method, and more particularly to a method and apparatus for generating multiple laser pulses using multiple Q switches. [Background technology]

[0002] Since the first laser, the ruby ​​laser, was developed in 1960 and entered the medical world, Nd:YAG lasers, helium-neon lasers, and dye lasers have been developed and have shown excellent effects in treating skin diseases. The basic principle of such lasers is that targets such as water, melanin, and oxyhemoglobin have their own vibration frequencies, and when a laser with a similar vibration frequency is irradiated, a reaction occurs in the specific target. This is the greatest feature of lasers, which allows selective treatment of targets, and is related to the absorption of each target, but the biggest difference is that while general light has many wavelengths, lasers always have one fixed wavelength. Due to these differences in wavelength, various laser materials have their own specific wavelengths, and laser types are divided into various types such as excimer, diode, CO2, and Nd:YAG depending on the medium.

[0003] Depending on the scope of application of lasers, there are lasers used in general hospitals for soft tissue surgery sites for incision, ulcers, tattoo removal, disinfection, etc., and lasers used in dentistry for hard and soft tissue for cavity removal, implant surgery, and hypersensitivity, etc., and there are many different types depending on the application. Looking at the history, ruby ​​and argon lasers were first used to treat nevus flame in 1963, and from the mid-1970s, argon and carbon dioxide lasers began to be used in earnest to treat vascular lesions, pigmentary diseases, and tumors. Recently, more diverse lasers have been developed and are being used to treat various skin diseases that were difficult or impossible to treat in the past. Currently, lasers used in the field of dermatology can be broadly divided into lasers used to treat various skin tumors and scars, lasers used to treat vascular diseases, and lasers used to treat tattoos. Recently, with growing interest in skin aging and skin regeneration, the functions of existing laser devices that were commonly used for the treatment of vascular and pigmented lesions and hair removal are showing a growing demand and are expanding to include skin lifting, elasticity, and regeneration functions.

[0004] Q-switched lasers are a representative technology that generates the most widely used short-pulse laser. Q-switched lasers are lasers with a short pulse width of 5 nanoseconds to 15 nanoseconds, and have high pulse power. For example, when the pulse width is 10 nanoseconds and the output energy is 1 J, the laser pulse power is as high as 100 MW. Due to the high power, there may be limitations to clinical use such as skin treatment.

[0005] To oscillate the Q-switched laser, a flash lamp is discharged and the light energy generated from the flash lamp is injected into the laser medium, causing density inversion in the laser medium to excite electrons, thereby generating laser resonance. The width of the light energy generated from the flash lamp is about 250 microseconds (μs), and the light energy generated during the pulse continuously excites electrons from the laser medium.

[0006] The Nd:YAG laser has a duration of about 230 μs in an excited state. The Q-switch signal is injected with a delay of about 150 μs after the start of the initial pumping, and a laser having a short pulse width and high peak power is oscillated. Here, even after the laser is oscillated, the light energy is continuously injected from the flash lamp, so that electrons are continuously excited in the laser medium Nd:YAG, but cannot contribute to the laser oscillation. In other words, after the Q-switch signal is applied, the light energy is no longer used, resulting in wasteful consumption of light energy and electrical energy. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Korean Patent No. 10-1229111 Summary of the Invention [Problem to be solved by the invention]

[0008] The technical problem to be solved by the technical concept of the present invention is to provide a method for generating multiple laser pulses using multiple Q switches, which can reduce the peak power of a laser and improve energy efficiency.

[0009] However, these problems are merely examples, and the technical idea of ​​the present invention is not limited thereto. [Means for solving the problem]

[0010] A multiple laser pulse oscillation method using multiple Q switches according to the technical idea of ​​the present invention for achieving the above technical object includes the steps of forming one cycle of optical energy, exciting electrons in a gain medium by the optical energy, performing a first Q switch during one cycle of the optical energy, oscillating a first laser pulse from the excited electrons of the gain medium by the first Q switch, performing a second Q switch during one cycle of the optical energy, and oscillating a second laser pulse from the excited electrons of the gain medium by the second Q switch.

[0011] In one embodiment of the present invention, the first Q switch may have a delay time in the range of 80 μs to 150 μs immediately after forming the optical energy.

[0012] In one embodiment of the present invention, the second Q switch may have a delay time in the range of 10 μs to 30 μs from the first Q switch.

[0013] In one embodiment of the present invention, the method may further include a step of performing a third Q switch after a delay time in the range of 10 μs to 30 μs has elapsed after performing the second Q switch during one cycle of the optical energy, and a step of oscillating a third laser pulse by the third Q switch.

[0014] In one embodiment of the present invention, the method may further include a step of performing a fourth Q switch after a delay time in the range of 10 μs to 30 μs has elapsed after performing the third Q switch during one cycle of the optical energy, and a step of oscillating a fourth laser pulse by the fourth Q switch.

[0015] In one embodiment of the present invention, the method may further include performing a fifth Q switch after a delay time in the range of 10 μs to 30 μs has elapsed after performing the fourth Q switch during one cycle of the optical energy, and oscillating a fifth laser pulse by the fifth Q switch.

[0016] In one embodiment of the present invention, the method may further include performing a sixth Q switch after a delay time in the range of 10 μs to 30 μs has elapsed after performing the fifth Q switch during one cycle of the optical energy, and oscillating a sixth laser pulse by the sixth Q switch.

[0017] In one embodiment of the present invention, the method may further include performing a seventh Q switch after a delay time in the range of 10 μs to 30 μs has elapsed after performing the sixth Q switch during one cycle of the optical energy, and oscillating a seventh laser pulse by the seventh Q switch.

[0018] In one embodiment of the present invention, one cycle of the light energy may be in the range of 200 μs to 350 μs.

[0019] A multiple laser pulse oscillation device using a multiple Q switch according to the technical idea of ​​the present invention is a multiple laser pulse oscillation device including a mirror, a wavelength section, a Q switch section, a polarization section, a gain medium section, an output coupler section, a first control section, and a second control section, and executes the following steps: forming one cycle of optical energy in the gain medium section by the first control section applying an electrical control signal; exciting electrons in the gain medium of the gain medium section by the optical energy; performing first Q switching in the Q switch section by the second control section applying an electrical control signal during one cycle of the optical energy; oscillating a first laser pulse by the first Q switch; performing second Q switching in the Q switch section during one cycle of the optical energy; and oscillating a second laser pulse by the second Q switch. Effect of the Invention

[0020] The multiple laser pulse oscillation method using multiple Q-switches according to the technical concept of the present invention can perform multiple Q-switches during one cycle of the generated optical energy to oscillate multiple laser pulses. Therefore, it is possible to provide an effect of reducing the output of the laser pulse to a desired level. In addition, it is possible to oscillate a laser pulse by using the energy of excited electrons that are not used when performing one Q-switch, so that it is possible to provide an efficient laser oscillation effect.

[0021] The above-mentioned effects of the present invention are described as examples, and the scope of the present invention is not limited to these effects. [Brief description of the drawings]

[0022] [Figure 1] 1 is a schematic diagram showing a multiple laser pulse oscillation device using multiple Q switches that implements a multiple laser pulse oscillation method using multiple Q switches according to the technical idea of ​​the present invention. [Diagram 2] 1 is a flowchart showing a method for generating multiple laser pulses using multiple Q switches according to the technical idea of ​​the present invention. [Diagram 3] 1 is a graph showing a result of performing a method for generating multiple laser pulses using multiple Q switches according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments of the present invention are provided to more completely explain the technical idea of ​​the present invention to those skilled in the art, and the following embodiments may be modified into various other forms, and the scope of the technical idea of ​​the present invention is not limited to the following embodiments. Rather, these embodiments are provided to make the present disclosure more complete and complete, and to fully convey the technical idea of ​​the present invention to those skilled in the art. In this specification, the same reference numerals refer to the same elements throughout. Furthermore, various elements and regions in the drawings are depicted in a schematic manner. Therefore, the technical idea of ​​the present invention is not limited by the relative sizes and intervals depicted in the accompanying drawings.

[0024] The technical idea of ​​the present invention is to operate the Q switch, for example, two or more times, for example, three or more times in one pulse period (for example, 230 μs to 330 μs), to generate three or more laser pulses in one cycle in the Q-switched laser, in order to reduce high laser oscillation peak power and maintain high output energy. Here, the pulse period means one light emission period of the flash lamp in the pulse power circuit for discharging the flash lamp. By operating the multiple Q switches at regular intervals in one pumping period of the laser, multiple Q-switch pulses are injected, so that the laser pulses can be made multiple, for example, three or more. As a result, the peak power of the laser pulse can be reduced. In addition, the Q-switch signal delay time can be adjusted, so that excited electrons can be efficiently used for laser oscillation, and the overall laser oscillation output energy can be increased. This can solve the problem of the conventional high single-pulse peak power, and can increase the total laser oscillation output energy, thereby expanding the possibility of clinical application.

[0025] FIG. 1 is a schematic diagram showing a multiple laser pulse oscillation device 100 using multiple Q switches, which implements a multiple laser pulse oscillation method using multiple Q switches according to the technical idea of ​​the present invention.

[0026] 1, a multiple laser pulse oscillator 100 includes a mirror 110, a wavelength section 120, a Q switch section 130, a polarizing section 140, a gain medium section 150, an output coupler section 160, a first control section 170, and a second control section 180. The mirror 110, the wavelength section 120, the Q switch section 130, the polarizing section 140, the gain medium section 150, and the output coupler section 160 may be arranged in the above-mentioned order.

[0027] The first control unit 170 is connected to the gain medium unit 150 and can apply an electrical signal to it. The second control unit 180 is connected to the Q switch unit 130 and can apply an electrical signal to it, and can further include a driver for the Q switch unit and a high voltage transformer. The gain medium unit 150 can include a gain medium such as a Nd:YAG rod, YVO4, Alexandrite, Ti:Sapphire rod, etc., and a flash lamp. The output coupler unit 160 can include a mirror. The wavelength unit 120 and the polarizer unit 140 can each have a flat plate shape.

[0028] The laser pulses oscillated by the multiple laser pulse oscillator 100 can be generated in the following manner.

[0029] FIG. 2 is a flow chart showing a method S100 for generating multiple laser pulses using multiple Q-switches according to the technical concept of the present invention.

[0030] Referring to FIG. 2, a method S100 for oscillating multiple laser pulses using multiple Q-switches includes a step S110 of forming one cycle of optical energy, a step S120 of exciting electrons in a gain medium by the optical energy, a step S130 of performing a first Q-switch during one cycle of the optical energy, a step S140 of oscillating a first laser pulse from the excited electrons in the gain medium by the first Q-switch, a step S150 of performing a second Q-switch during one cycle of the optical energy, and a step S160 of oscillating a second laser pulse from the excited electrons in the gain medium by the second Q-switch.

[0031] 1, when the first control unit 170 applies an electrical control signal to the gain medium unit 150, the voltage and current of the flash lamp included in the gain medium unit 150 are increased and then decreased to generate one period of light energy. Electrons of the gain medium included in the gain medium unit 150 are excited by the light energy.

[0032] Then, when the second control unit 180 applies an electrical control signal to the Q switch unit 130 during one cycle of the optical energy to perform the first Q switch, a laser pulse is externally oscillated from the electrons excited in the gain medium. The laser pulse can be reflected in the opposite direction by the mirror 110 and oscillated externally by passing through the wavelength unit 120, the polarizing unit 140, and the output coupler unit 160. If necessary, the laser pulse can be reflected in the opposite direction by the output coupler unit 160. Also, if necessary, the laser pulse can be polarized by the polarizing unit 140 and oscillated with a different direction.

[0033] Then, during one cycle of the optical energy, the second control unit 180 applies an electrical control signal to the Q switch unit 130 to perform a second Q switch, and a laser pulse is again oscillated to the outside from the electrons excited in the gain medium. Here, the technical idea of ​​the present invention is that the first Q switch and the second Q switch are performed during one cycle of the optical energy.

[0034] Then, in the same manner, the third to seventh Q switches can be performed during one cycle of the optical energy to generate the third to seventh laser pulses, respectively. Here, the seventh Q switch is merely illustrative, and performing any n number of Q switches is within the technical spirit of the present invention.

[0035] The first Q switch may have a delay time in the range of 80 μs to 150 μs immediately after forming the optical energy.

[0036] The second Q switch may have a delay time in the range of 10 μs to 30 μs from the first Q switch.

[0037] The method may further include a step of performing a third Q switch after a delay time in the range of 10 μs to 30 μs has elapsed after performing the second Q switch during one cycle of the optical energy, and a step of oscillating a third laser pulse by the third Q switch.

[0038] The method may further include a step of performing a fourth Q switch after a delay time in the range of 10 μs to 30 μs has elapsed after performing the third Q switch during one cycle of the optical energy, and a step of oscillating a fourth laser pulse by the fourth Q switch.

[0039] The method may further include a step of performing a fifth Q switch after a delay time in the range of 10 μs to 30 μs has elapsed after performing the fourth Q switch during one cycle of the optical energy, and a step of oscillating a fifth laser pulse by the fifth Q switch.

[0040] The method may further include a step of performing a sixth Q switch after a delay time in the range of 10 μs to 30 μs has elapsed after performing the fifth Q switch during one cycle of the optical energy, and a step of oscillating a sixth laser pulse by the sixth Q switch.

[0041] The method may further include a step of performing a seventh Q switch after a delay time in the range of 10 μs to 30 μs has elapsed after performing the sixth Q switch during one cycle of the optical energy, and a step of oscillating a seventh laser pulse by the seventh Q switch.

[0042] Here, the above delay times are exemplary and may have various time ranges.

[0043] Furthermore, by using the above-mentioned method, the above-mentioned light energy can be repeatedly generated as the next cycle, and the Q-switching can be repeatedly performed in the same manner.

[0044] FIG. 3 is a graph showing the results of performing a method for generating multiple laser pulses using multiple Q switches according to an embodiment of the present invention.

[0045] Referring to Figure 3, the voltage and current of the flash lamp are shown, and it can be seen that one cycle of light energy is provided. One cycle of the light energy is in the range of about 200μs to about 350μs. Eight Q-switch pulse peaks indicating eight Q-switches during one cycle of the light energy and eight laser pulse output peaks oscillated thereby are shown.

[0046] The delay time from the time when the flash lamp voltage is applied to the first Q-switch pulse may be in the range of about 80 μs to about 150 μs. The delay time from the first Q-switch pulse to the second Q-switch pulse may be in the range of about 15 μs to about 35 μs. The delay time from the first Q-switch pulse to the third Q-switch pulse may be in the range of about 40 μs to about 60 μs. The delay time from the first Q-switch pulse to the fourth Q-switch pulse may be in the range of about 65 μs to about 85 μs. The delay time from the first Q-switch pulse to the fifth Q-switch pulse may be in the range of about 90 μs to about 110 μs. The delay time from the first Q-switch pulse to the sixth Q-switch pulse may be in the range of about 115 μs to about 135 μs. The delay time from the first Q-switch pulse to the seventh Q-switch pulse may be in the range of about 140 μs to about 160 μs.

[0047] In conventional Q-switched lasers, electrons are accumulated in an excited state in the gain medium until the Q-switch is turned on, and when the Q-switch is turned on, the accumulated excited electrons are stimulated and resonate to oscillate the laser. When Q-switching is performed once, the laser continues to receive light energy even after the Q-switch delay time, and the electrons continue to change to an excited state, but since Q-switching is not performed any more within one cycle of light energy, no further laser oscillation occurs within the above one cycle of light energy.

[0048] However, according to the multiple laser pulse oscillation method using multiple Q-switches according to the technical concept of the present invention, since Q-switching is performed continuously with one cycle of optical energy, it is possible to have a higher efficiency in using excited electrons, and the laser can oscillate continuously, so that the overall laser pumping energy can be used effectively.

[0049] It will be apparent to those having ordinary skill in the art to which the technical idea of ​​the present invention pertains that the technical idea of ​​the present invention described above is not limited to the above-mentioned embodiments and the attached drawings, and various substitutions, modifications and alterations are possible within the scope not departing from the technical idea of ​​the present invention. [Industrial Applicability]

[0050] The technical concept of the present invention can be utilized in a laser generation method.

Claims

1. forming a cycle of light energy; exciting electrons in a gain medium with the optical energy; performing a first Q-switch during one cycle of the optical energy; generating a first laser pulse from the excited electrons in the gain medium by the first Q-switch; performing a second Q-switch during one cycle of the optical energy; generating a second laser pulse from the excited electrons in the gain medium by the second Q-switch.

2. 2. The method of claim 1, wherein the first Q switch is a multiple Q switch having a delay time in the range of 80 μs to 150 μs immediately after forming the optical energy.

3. 2. The method of claim 1, wherein the second Q switch is a multiple Q switch having a delay time in the range of 10 μs to 30 μs from the first Q switch.

4. performing a third Q-switch after a delay time in the range of 10 μs to 30 μs has elapsed after performing the second Q-switch during one cycle of the optical energy; 2. The method for generating multiple laser pulses using multiple Q-switches according to claim 1, further comprising the step of: generating a third laser pulse by the third Q-switch.

5. performing a fourth Q-switch after a delay time in the range of 10 μs to 30 μs has elapsed after performing the third Q-switch during one cycle of the optical energy; The method for generating multiple laser pulses using multiple Q-switches according to claim 4 , further comprising the step of: generating a fourth laser pulse by the fourth Q-switch.

6. performing a fifth Q-switch after a delay time in the range of 10 μs to 30 μs has elapsed after performing the fourth Q-switch during one cycle of the optical energy; 6. The method for generating multiple laser pulses using multiple Q-switches according to claim 5, further comprising the step of: generating a fifth laser pulse by the fifth Q-switch.

7. performing a sixth Q-switch after a delay time in the range of 10 μs to 30 μs has elapsed after performing the fifth Q-switch during one cycle of the optical energy; The method for generating multiple laser pulses using multiple Q-switches according to claim 6 , further comprising the step of: generating a sixth laser pulse by the sixth Q-switch.

8. performing a seventh Q-switch after a delay time in the range of 10 μs to 30 μs has elapsed after performing the sixth Q-switch during one cycle of the optical energy; The method for generating multiple laser pulses using multiple Q-switches according to claim 7 , further comprising the step of: generating a seventh laser pulse by the seventh Q-switch.

9. 2. The method for multiple laser pulse oscillation according to claim 1, using multiple Q switches, wherein one cycle of the optical energy is in the range of 200 μs to 350 μs.

10. A multiple laser pulse oscillation device including a mirror, a wavelength section, a Q-switch section, a polarizing section, a gain medium section, an output coupler section, a first control section, and a second control section, applying an electrical control signal from the first control unit to generate one cycle of optical energy in the gain medium; a step of exciting electrons in a gain medium of the gain medium portion by the optical energy; performing a first Q switch in the Q switch unit by applying an electrical control signal by the second control unit during one cycle of the optical energy; generating a first laser pulse by the first Q-switch; performing a second Q-switch in the Q-switch unit during one cycle of the optical energy; and generating a second laser pulse by the second Q switch.

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