Method for light emission regulation of up-conversion luminescent material and deep ultraviolet laser

Abstract

The application discloses a luminescence regulation method of up-conversion luminescence material and a deep ultraviolet laser. By adjusting the pulse duty cycle of an incident laser light source, a plurality of rare earth elements contained in the up-conversion luminescence material absorb the energy of the incident laser light, and after different energy transfer up-conversion and inter-system relaxation processes, deep ultraviolet fluorescence is finally radiated. In the conversion process of the up-conversion fluorescence, the pulse duty cycle of the incident laser light source is adjusted in the method, the regulation of the energy transfer process between different energy levels is realized, the residence time of carriers in different energy levels is controlled, the deep ultraviolet band luminescence efficiency is significantly improved, the interference of the visible light region and the infrared region fluorescence peak can be inhibited, and the principle is simple and universal.

Description

Technical Field

[0001] This application relates to the field of deep ultraviolet laser technology, and in particular to a method for controlling the luminescence of an upconversion luminescent material and a deep ultraviolet laser. Background Technology

[0002] UVC deep ultraviolet lasers have advantages such as short wavelength, concentrated energy, and high resolution, and have broad application prospects in fields such as sterilization, fisheries, plant lighting, phototherapy, and military applications.

[0003] However, deep ultraviolet (DUV) lasers have long lacked practical application and precision, hindering the development of UVC deep ultraviolet instruments and cutting-edge research. Currently, the commonly used method utilizes all-solid-state lasers as the fundamental frequency source, generating UVC deep ultraviolet lasers through nonlinear frequency doubling schemes. However, this method has high material requirements and complex systems, and the only currently available KBBF crystal capable of outputting UVC deep ultraviolet lasers contains highly toxic elements and is difficult to grow, limiting its commercial application. Upconversion luminescent materials, due to their ability to convert low-energy, long-wavelength photons into high-energy photons, are considered an important means of achieving deep ultraviolet fluorescence. Currently, the pressing problem for upconversion materials is the large non-radiative transition loss and low upconversion energy transfer efficiency, which limits the development and practical application of deep ultraviolet fluorescent devices, leading to a bottleneck in the research and development of deep ultraviolet luminescent devices.

[0004] Therefore, existing technologies need to be improved. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide users with a method for controlling the luminescence of upconversion luminescent materials and a deep ultraviolet laser, overcoming the defects of large nonradiative transition losses and low upconversion energy transfer efficiency in the prior art.

[0006] The technical solution adopted by this invention to solve the technical problem is as follows:

[0007] In a first aspect, this embodiment discloses a method for controlling the luminescence of an upconversion luminescent material, comprising:

[0008] By adjusting the pulse duty cycle of the incident laser source, the various rare earth elements contained in the upconversion luminescent material absorb the energy of the incident laser and then radiate deep ultraviolet fluorescence through different energy transfer upconversion and intersystem relaxation processes.

[0009] Optionally, the step of adjusting the duty cycle of the incident laser source pulse includes:

[0010] Gradually reduce the pulse duty cycle of the incident laser.

[0011] Optionally, the incident laser source is an infrared pulsed laser generated by a 980nm near-infrared pulsed laser.

[0012] Optionally, the adjustment of the incident laser source pulse duty cycle also includes the step of:

[0013] The period of the incident laser is controlled to be 50ms and the pulse width of the incident laser is within 0-50ms.

[0014] Optionally, the frequency of the laser source is set to 10Hz-200Hz.

[0015] Optionally, the step in which the various rare earth elements contained in the upconversion luminescent material absorb the energy of the incident laser and then radiate deep ultraviolet fluorescence through different energy transfer upconversion and intersystem relaxation processes includes:

[0016] Yb 3+ When ions receive incident laser energy and are sensitized by incident photons, they transfer the energy to Tm. 3+ ion;

[0017] Tm 3+ After undergoing multiple stages of energy upconversion, ions achieve multi-band upconversion emission.

[0018] Gd 3+ Ion absorption from Tm 3+ After undergoing upconversion fluorescence via intersystem relaxation transfer, the ions emit deep ultraviolet fluorescence.

[0019] Optionally, the Gd 3+ Ion absorption from Tm 3+ The steps involved in the upconversion fluorescence of ions after intersystem relaxation transfer, followed by the emission of deep ultraviolet fluorescence, include:

[0020] Tm 3+ The upconversion fluorescence of ions via intersystem relaxation transfer is affected by Gd 3+ After the ion's energy level absorbs, Gd 3+ The ions emit deep ultraviolet fluorescence with a wavelength of 310 nm.

[0021] Optionally, the upconversion luminescent material is Yb. 3+ -Tm 3+ -Gd 3+ Co-doped upconversion glass crystal.

[0022] Secondly, this embodiment discloses a method for controlling the luminescence of an upconversion luminescent material, comprising:

[0023] By adjusting the duty cycle of the incident laser source pulse to the nanosecond level, the various rare earth elements contained in the upconversion luminescent material absorb the energy of the incident laser and then radiate deep ultraviolet lasers through different energy transfer upconversion and intersystem relaxation processes.

[0024] Thirdly, this embodiment discloses a deep ultraviolet laser, wherein deep ultraviolet fluorescence or deep ultraviolet laser is emitted using the light emission modulation method of the upconversion luminescent material.

[0025] This invention discloses a method for controlling the luminescence of an upconversion luminescent material and a deep ultraviolet laser. By adjusting the pulse duty cycle of the incident laser source, various rare earth elements contained in the upconversion luminescent material absorb the energy of the incident laser and, after undergoing different energy transfer upconversion and intersystem relaxation processes, radiate deep ultraviolet fluorescence. In this embodiment, the method controls the energy transfer between different energy levels by adjusting the pulse duty cycle of the incident light source during the upconversion fluorescence conversion process, thereby controlling the residence time of charge carriers at different energy levels. This significantly improves the luminescence efficiency in the deep ultraviolet band and suppresses interference from fluorescence peaks in the visible and infrared regions. The luminescence control method disclosed in this embodiment is simple in principle and has universality. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating the steps of the luminescence modulation method for upconversion luminescent materials in an embodiment of the present invention.

[0027] Figure 2 This is a flowchart illustrating the steps of the luminescence modulation method for upconversion luminescent materials in a specific application embodiment of the present invention.

[0028] Figure 3 This is a result diagram of the upconversion deep ultraviolet luminescence modulation method in an embodiment of the present invention;

[0029] Figure 4 This is the time-dependent spectrum of the two peaks under an excitation source with a pulse high-level time of 40ms in an embodiment of the present invention;

[0030] Figure 5 This is the time-dependent spectrum of the two peaks under an excitation source with a pulse high-level time of 10ms in an embodiment of the present invention;

[0031] Figure 6 This is the time-dependent spectrum of the two peaks under an excitation source with a pulse high-level time of 1.50 ms in an embodiment of the present invention;

[0032] Figure 7 This is the laser spectrum under nanosecond laser pumping in an embodiment of the present invention;

[0033] Figure 8This is the intensity-incident power curve under nanosecond laser pumping in an embodiment of the present invention. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0035] Deep ultraviolet (DUV) emission characteristics refer to the characteristic spectrum emitted by materials with a center wavelength between 200 nm and 350 nm. Since the invention of GaN-based UV LEDs at the end of the 20th century, DUV light-emitting devices have been widely used in practical fields such as precision instruments, industrial curing, catalysis, water purification, and medical applications.

[0036] Upconversion luminescent materials are considered an important means of achieving deep ultraviolet fluorescence. However, a pressing problem for upconversion materials is the large nonradiative transition loss and low upconversion energy transfer efficiency. This significantly limits the development and practical application of deep ultraviolet fluorescent devices, leading to a bottleneck in the research and development of deep ultraviolet luminescent devices.

[0037] Currently, some research groups are focusing on the microstructure of materials and doping with different elements, introducing core-shell / multi-shell structures to enhance specific emission wavelengths by controlling energy transfer pathways or modifying surfaces. However, current deep ultraviolet (DUV) luminescent materials still suffer from unavoidable visible-region fluorescence interference, necessitating the addition of filters for purification in practical applications, thus increasing costs. Therefore, to achieve high-quality DUV upconversion fluorescence and reduce industrial application costs, it is necessary to invent a luminescence modulation method to screen out the desired short-wavelength fluorescence.

[0038] To address the aforementioned issues, this embodiment proposes a method for controlling the luminescence of upconversion luminescent materials and a deep-ultraviolet laser. By adjusting the pulse duty cycle of the incident laser source incident on the upconversion luminescent material, and as the pulse duty cycle decreases sequentially, energy transfer occurs between different energy levels of the rare-earth ions contained in the upconversion luminescent material. After multiple energy level upconversion transfers, upconversion fluorescence in the deep-ultraviolet region is excited. The method provided in this embodiment achieves the excitation of upconversion fluorescence in the deep-ultraviolet region simply by adjusting the pulse duty cycle of the incident laser; therefore, its implementation principle is simple and it has broad applicability.

[0039] The embodiments disclosed in this invention will now be described in more detail with reference to the accompanying drawings.

[0040] Firstly, this embodiment discloses a method for controlling the luminescence of an upconversion luminescent material, such as... Figure 1 As shown, it includes:

[0041] Step S1: Adjust the duty cycle of the incident laser source pulse.

[0042] The equipment used in this embodiment includes: a laser light source, a pulse generator, an upconversion luminescent material, and a spectrometer.

[0043] A laser source is used to emit incident laser light. In this step, during the adjustment of the incident laser pulse duty cycle, the period of the incident laser is controlled to be 50ms and the pulse width is controlled to be between 0-50ms, while the high-level time of the incident laser pulse is gradually reduced from 40ms to 0.5ms. The fluorescence emission from the upconversion luminescent material is modulated by controlling the gradual decrease in the pulse duty cycle.

[0044] Furthermore, in this embodiment, the incident laser source is an infrared pulsed laser generated by a 980nm near-infrared pulsed laser, and the frequency of the laser source is set to a range of 10Hz-200Hz during the adjustment of the laser pulse duty cycle in order to obtain a stable incident laser.

[0045] A pulse generator is used to modulate the laser emitted by a laser source. In practice, the laser beam emitted by the laser source is first modulated using a pulse generator to obtain an excitation source with a preset fixed frequency. Then, a convex lens placed in the laser optical path focuses the laser beam, which is then incident on the upconversion luminescent material.

[0046] The upconversion luminescent material includes a microcrystalline carrier and rare earth ions doped into the microcrystalline carrier. Specifically, the upconversion luminescent material used in this embodiment contains multiple rare earth ions. In one implementation, the rare earth ions used in this embodiment include Yb. 3+ Ions, Tm 3+ Ions and Gd 3+ There are three types of ions. Among them, Yb 3+ Ions, Tm 3+ Ions and Gd 3+ The percentage range of ion doping molar numbers is: Yb 4-19%, Tm 0.02-0.15%, Gd 3-14%, therefore the upconversion luminescent material is Yb. 3+ -Tm 3+ -Gd 3+ Co-doping yields an upconversion luminescent material. In a specific implementation, this upconversion luminescent material is Yb. 3+ -Tm 3+ -Gd 3+ Co-doped upconversion glass crystal.

[0047] Step S2: After absorbing the energy of the incident laser, the various rare earth elements contained in the upconversion luminescent material undergo different energy transfer upconversion and intersystem relaxation processes, and then emit deep ultraviolet fluorescence.

[0048] The rare earth ions contained in the upconversion luminescent material absorb energy from the incident laser and then undergo upconversion through energy transfer between multiple energy levels and intersystem relaxation processes to excite deep ultraviolet fluorescence with a wavelength of 310 nm.

[0049] Specifically, the steps by which the various rare earth elements contained in the upconversion luminescent material emit deep ultraviolet fluorescence after undergoing different energy transfer upconversion and intersystem relaxation processes include:

[0050] Yb 3+ When ions receive incident laser energy and are sensitized by incident photons, they transfer the energy to Tm. 3+ ion;

[0051] Tm 3+ After undergoing multiple energy upconversions, ions emit upconversion fluorescence at different energy levels.

[0052] Gd 3+ Ion absorption from Tm 3+ After undergoing upconversion fluorescence via intersystem relaxation transfer, the ions emit deep ultraviolet fluorescence.

[0053] In detail, the above-mentioned conversion luminescent material is Yb 3+ -Tm 3+ -Gd 3+ Taking co-doped upconversion glass as an example, in this step, the period of the incident laser is first controlled to be less than 0-50ms. When the upconversion glass is excited by a 980nm pulsed light source with a pulse high-level time of 40ms, the Yb in the upconversion glass... 3+ In ion absorption incident laser light, photon energy is sensitized and transferred to Tm. 3+ Ions, Tm 3+ The ions absorb and emit photons at the 800nm ​​energy level. When the upconversion glass is excited by a 980nm pulsed light source with a pulse high-level time of 10ms, the incident energy passes through the Yb 3+ Passed to Tm 3+ Tm 3+ The ion's 470nm energy level absorbs and emits photons. When the upconversion glass crystal is excited by a 980nm pulsed laser with a high-level pulse duration of 0.5ms, the incident energy passes through the Yb 3+ Ions and Tm 3+ Ions are Gd 3+ The 310nm energy level absorbs and emits photons. When the upconversion glass crystal is excited with a nanosecond pulse light source, Gd 3+The 310nm energy level gains optical gain and emits deep ultraviolet fluorescence, therefore Tm 3+ The upconversion fluorescence of ions via intersystem relaxation transfer is affected by Gd 3+ After the ion's energy level absorbs, Gd 3+ The ions emit deep ultraviolet fluorescence with a wavelength of 310 nm.

[0054] Combination Figure 2 As shown, taking a specific application example of this embodiment as an example, the method provided by the present invention will be described in further detail.

[0055] The upconversion luminescent material used in this embodiment is Yb. 3+ -Tm 3+ -Gd 3+ Take co-doped upconversion glass as an example.

[0056] Yb in upconversion glass 3+ It absorbs the energy of the incident photons and transfers the energy to Tm. 3+ After that, Tm 3+ The fluorescence emitted at different energy levels of 800 nm, 476 nm, 450 nm, 361 nm, and 347 nm in sequence. Through energy transfer upconversion and intersystem relaxation processes, it was ultimately converted by GdO2. 3+ The energy level is captured and emits deep ultraviolet fluorescence at 310 nm. The luminescence modulation method in this embodiment is achieved by adjusting the duty cycle of the incident laser pulse. When the duty cycle is gradually decreased from a high 40 ms to 0.5 ms, the main peak of the emission spectrum is progressively modulated from 800 nm to 476 nm to 310 nm. The modulation result is shown in the figure below. Figure 3 As shown.

[0057] H1. An upconversion glass crystal is excited by a 980nm pulsed laser with a pulse width of 40ms. At this time, a large amount of energy is converted to Tm. 3+ The 800nm ​​energy level absorbs and emits photons, with a small number of photons being transferred to the next energy level. At this point, 800nm ​​becomes the main peak, such as... Figure 4 As shown.

[0058] H2, an upconversion glass crystal is excited by a 980nm pulsed light source with a pulse high-level time of 10ms, and the incident energy is converted by Tm. 3+ The 470nm energy level absorbs and emits photons, with a small number of photons transferred to the next energy level. At this point, 470nm becomes the main peak, and the next energy level begins to absorb more photons. The emission ratio at 800nm ​​decreases significantly, as shown in the attached diagram. Figure 5 As shown.

[0059] Furthermore, in combination Figure 5As shown, under pump light excitation with incident light at 980 nm, the fluorescence intensity ratio at 310 nm / 800 nm changes from 1 / 60 at 40 ms to 200 / 1 at 0.5 ms, significantly suppressing interference peaks in the visible and infrared regions. This is a characteristic rarely found in other deep ultraviolet upconversion materials. This phenomenon can be demonstrated by the time-dependent spectra of different emission peaks under different pulse widths; the ratio of the spectral integral area at a pulse width of 40 ms is much smaller than that at 0.5 ms.

[0060] H3. An upconversion microcrystalline glass is excited by a 980nm pulsed laser with a high-level pulse duration of 0.5ms. The incident energy is converted by Gd... 3+ The 310nm energy level absorbs and emits photons, with most photons being absorbed and remaining at this energy level. In this case, 310nm becomes the main peak, as shown in the attached diagram. Figure 6 As shown.

[0061] H4, Gd upconversion glass-ceramics are excited by nanosecond pulse light sources. 3+ The 310nm energy level achieves optical gain, emitting high-quality laser light, with a laser spectrum as follows: Figure 7 As shown, the relative intensity versus incident power curve is as follows: Figure 8 As shown.

[0062] This invention is based on an adjustable pulse width excitation source and Yb 3+ -Tm 3+ -Gd 3+ Co-doped upconversion glass-ceramics are used in pulse generators to produce a 980nm excitation source at a specific frequency, and fluorescence emission is controlled by adjusting the pulse duty cycle. Upconversion fluorescent glass is used to receive the incident light energy after it has been focused by a lens. The Yb in the upconversion glass-ceramics... 3+ It will first be sensitized by the incident photon, and then gradually transfer energy to Tm. 3+ and Gd 3+ By controlling the pulse width of the incident laser source, upconversion emission of different wavelengths can be achieved.

[0063] In addition to the above-disclosed luminescence modulation method for controlling deep ultraviolet fluorescence, this embodiment discloses a luminescence modulation method for upconversion luminescent materials, the method comprising:

[0064] By adjusting the pulse duty cycle of the incident laser source, the various rare earth elements contained in the upconversion luminescent material absorb the energy of the incident laser and then radiate deep ultraviolet lasers through different energy transfer upconversion and intersystem relaxation processes.

[0065] That is, by using the above-mentioned light emission control method to control the pulse duty cycle of the incident laser source to reach a preset range, so that after the incident laser source irradiates the upconversion luminescent material, the rare earth elements in the upconversion luminescent material absorb the energy of the incident laser and radiate deep ultraviolet laser.

[0066] Specifically, when adjusting the duty cycle of the incident laser source pulse, the incident laser is emitted directly from the nanosecond source when it is at the nanosecond level, and the high-level time of the nanosecond source is adjusted to 6ns, thereby achieving the excitation of deep ultraviolet laser.

[0067] In specific implementation, the incident laser source is an infrared pulsed laser generated by a 980nm nanosecond near-infrared pulsed laser, and the frequency setting range of the laser source is 10Hz-200Hz. The pulse width of the incident laser is controlled in the nanosecond range, and the high-level time of the incident laser pulse is controlled at 6ns. This is used to upconvert the Yb in the microcrystalline glass. 3+ When ions receive incident laser energy and are sensitized by incident photons, they transfer the energy to Tm. 3+ Ions; Tm 3+ After undergoing multiple stages of energy upconversion, the ions emit upconversion fluorescence at different energy levels; when the high-level duration of the incident laser pulse is set to a nanosecond pulse, Gd 3+ Ion absorption from Tm 3+ After undergoing upconversion fluorescence via intersystem relaxation transfer, the ions emit deep ultraviolet laser light.

[0068] On the other hand, based on the above-mentioned control method, this embodiment also provides a deep ultraviolet laser that uses the luminescence control method of the upconversion luminescent material disclosed in this embodiment to radiate deep ultraviolet fluorescence or deep ultraviolet laser.

[0069] The deep ultraviolet laser is a deep ultraviolet microcavity laser, comprising: a microcrystalline carrier and rare earth ions doped within the microcrystalline carrier. Specifically, in this embodiment, the rare earth ions include: Yb 3+ Ions, Tm 3+ Ions and Gd 3+ Ions. The microcrystalline carrier serves as the substrate for the laser, and rare earth ions are directly and uniformly grown inside the microcrystalline carrier.

[0070] Microcrystalline glass possesses excellent properties such as high mechanical strength, excellent insulation performance, low dielectric loss, stable dielectric constant, adjustable thermal expansion coefficient, resistance to chemical corrosion, wear resistance, good thermal stability, and high operating temperature. Therefore, microcrystalline carriers, as substrate materials, improve the thermal stability and chemical stability of deep ultraviolet microcavity lasers, thereby enhancing the deep ultraviolet laser emission stability and lifespan of microcavity lasers.

[0071] This invention discloses a method for controlling the luminescence of upconversion luminescent materials and a deep-ultraviolet laser. The method utilizes different duty cycles of the laser source to achieve deep-ultraviolet upconversion fluorescence. During this upconversion fluorescence conversion process, the energy transfer between different energy levels is achieved by adjusting the pulse duty cycle of the incident laser source, thereby controlling the residence time of charge carriers at different energy levels. The method provided in this embodiment significantly improves the luminescence efficiency in the deep-ultraviolet band and suppresses interfering fluorescence peaks in the visible and infrared regions. It is simple in principle, convenient to implement, and has wide applicability.

[0072] The embodiments described above are merely examples of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application.

Claims

1. A method for controlling the luminescence of an upconversion luminescent material, characterized in that, include: The upconversion luminescent material is Yb 3+ -Tm 3+ -Gd 3+ Co-doped upconversion glass crystals; By gradually reducing the pulse duty cycle of the incident laser source, the various rare earth elements contained in the upconversion luminescent material absorb the energy of the incident laser and, after undergoing different energy transfer upconversion and intersystem relaxation processes, radiate deep ultraviolet fluorescence; the incident laser source is an infrared pulse laser generated by a 980nm near-infrared pulse laser. During the adjustment of the duty cycle of the incident laser pulse, the period and pulse width of the incident laser are controlled, and the high-level time of the incident laser pulse is gradually reduced. As the duty cycle is gradually decreased from high, the main peak of the emission spectrum is gradually modulated from 800nm ​​to 476nm to 310nm. Yb in upconversion glass 3+ It absorbs the energy of the incident photons and transfers the energy to Tm. 3+ After that, Tm 3+ The fluorescence emitted at different energy levels sequentially undergoes energy transfer upconversion and intersystem relaxation processes, and is ultimately converted by Gd. 3+ The energy level captures and emits deep ultraviolet fluorescence at 310 nm.

2. The luminescence modulation method for upconversion luminescent materials according to claim 1, characterized in that, The adjustment of the incident laser source pulse duty cycle also includes the following steps: The period of the incident laser is controlled to be 50ms and the pulse width of the incident laser is kept below 50ms.

3. The luminescence modulation method for upconversion luminescent materials according to claim 1, characterized in that, The frequency of the incident laser source is set to 10Hz-200Hz.

4. The method for controlling the luminescence of the upconversion luminescent material according to any one of claims 1-3, characterized in that, The steps by which the various rare earth elements contained in the upconversion luminescent material absorb the energy of the incident laser and radiate deep ultraviolet fluorescence after undergoing different energy transfer upconversion and intersystem relaxation processes include: Yb 3+ When ions receive incident laser energy and are sensitized by incident photons, they transfer the energy to Tm. 3+ ion; Tm 3+ After undergoing multiple stages of energy upconversion, ions achieve multi-band upconversion emission. Gd 3+ Ion absorption from Tm 3+ After undergoing upconversion fluorescence via intersystem relaxation transfer, the ions emit deep ultraviolet fluorescence.

5. The luminescence modulation method for upconversion luminescent materials according to claim 4, characterized in that, The Gd 3+ Ion absorption from Tm 3+ The steps involved in the upconversion fluorescence of ions after intersystem relaxation transfer, followed by the emission of deep ultraviolet fluorescence, include: Tm 3+ The upconversion fluorescence of ions via intersystem relaxation transfer is affected by Gd 3+ After the ion's energy level absorbs, Gd 3+ The ions emit deep ultraviolet fluorescence with a wavelength of 310 nm.

6. A method for controlling the luminescence of an upconversion luminescent material, characterized in that, include: By adjusting the duty cycle of the incident laser pulse, the various rare earth elements contained in the upconversion luminescent material absorb the energy of the incident laser and, after undergoing different energy transfer upconversion and intersystem relaxation processes, radiate deep ultraviolet laser light; the upconversion luminescent material is Yb. 3+ -Tm 3+ -Gd 3+ Co-doped upconversion glass crystals; The incident laser source is an infrared pulsed laser generated by a 980nm near-infrared pulsed laser; Yb in upconversion glass 3+ It absorbs the energy of the incident photons and transfers the energy to Tm. 3+ After that, Tm 3+ Gd emits fluorescence at different energy levels sequentially, undergoing energy transfer upconversion and intersystem relaxation processes. 3+ Ion absorption from Tm 3+ After upconversion fluorescence of ions via intersystem relaxation transfer, Gd 3+ The corresponding energy level of the ion gains optical gain and emits a 310nm deep ultraviolet laser.

7. A deep ultraviolet laser, characterized in that, Deep ultraviolet fluorescence can be emitted using the luminescence modulation method of the upconversion luminescent material as described in any one of claims 1-5, or deep ultraviolet laser can be emitted using the luminescence modulation method of the upconversion luminescent material as described in claim 6.

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