Common-cavity independent gain channel dual-wavelength laser

Abstract

The invention discloses a common-cavity independent gain channel dual-wavelength laser which comprises a pumping source, a coupling system, a total reflection cavity mirror, a gain medium pair and an output cavity mirror which are sequentially arranged along a light path, the gain medium pair comprises a first laser medium and a second laser medium, and the first laser medium and the second laser medium are arranged in a compact serial mode; light output by the pumping source forms a focused light beam through the coupling system, and the light beam enters the gain medium pair through the total reflection cavity mirror; a laser resonant cavity is formed between the total reflection cavity mirror and the output cavity mirror, the first laser medium and the second laser medium respectively provide gains to generate laser with corresponding wavelengths, and the two laser wavelengths do not compete with each other. According to the technical scheme, the two laser media share the pumping source and the coupling system and oscillate in the same resonant cavity, so that the whole system is a laser, dual-wavelength same-light-path output is achieved, a beam combining device is omitted, the structure is more compact, the manufacturing cost is low, the system is stable, operation is convenient, and practicability is good.

Description

Technical Field

[0001] The present invention relates to the field of laser and optoelectronic technologies, and particularly to a common-cavity independent gain-channel dual-wavelength laser. Background Art

[0002] Dual-wavelength lasers have important applications in the fields of laser communication, atmospheric and environmental detection, biomedicine, etc. For example, in the field of atmospheric and environmental detection, dual-wavelength lasers can be used in differential absorption lidar and air pollution monitoring to perform high-precision analysis on the absorption characteristics of specific gases at different wavelengths; in optical coherence tomography, dual-wavelength lasers can penetrate different tissue depths to achieve high-resolution biomedical imaging; the dual-wavelength difference frequency technology can generate coherent radiation in the mid-infrared or terahertz band. Therefore, dual-wavelength lasers have always attracted the attention of researchers and application personnel at home and abroad.

[0003] Existing related dual-wavelength laser applications usually require the output of stable dual-wavelength laser in the same optical path. At present, many literatures have also reported dual-wavelength lasers based on a single gain medium, such as the 1064nm and 1319nm dual-wavelength, 1319 and 1338nm dual-wavelength lasers based on Nd:YAG crystals, etc. However, since the two wavelengths come from the same gain medium, there is a problem of gain competition, and only balanced dual-wavelength output can be achieved under specific gain conditions, with relatively poor intensity stability, which limits the applications in many fields. In order to achieve stable dual-wavelength laser output, usually two lasers are used. For example, the existing Chinese patent CN202411429799.6 discloses "a dual-wavelength laser output system, including: a first laser for generating laser of a first wavelength; a second laser for generating laser of a second wavelength; an edge computing node configured near the first laser and the second laser, responsible for real-time processing and analysis of the laser data of the first wavelength and the second wavelength; a distributed computing framework for fragmenting and distributing the laser data to multiple edge computing nodes for processing; a nonlinear optical crystal configured on the laser output path for converting and synthesizing the laser of the first wavelength and the second wavelength. Through the dual lasers and the nonlinear optical crystal, multi-wavelength output is achieved, real-time data processing and fault detection are performed using the edge computing node, and efficient data processing, storage and flexible deployment are ensured through the distributed computing framework and the database, improving the system stability and accuracy" technical solution. This technical solution uses two lasers, resulting in high manufacturing costs, and for the same optical path application, further beam combination is required, the system is complex, inconvenient to operate during use, and has poor practicability. Summary of the Invention

[0004] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a common-cavity independent gain-channel dual-wavelength laser with reasonable structural design, compact structure, low manufacturing cost, stable system, convenient operation and good practicability.

[0005] To achieve the above object, the present invention provides the following technical solutions: A common cavity independent gain channel dual-wavelength laser, comprising a pump source, a coupling system, a total reflection cavity mirror, a gain medium pair, and an output cavity mirror arranged in sequence along the optical path. The gain medium pair includes a first laser medium and a second laser medium, and the first laser medium and the second laser medium are placed in a compact series type; the light output by the pump source forms a focused beam through the coupling system, and the beam is incident on the gain medium pair through the total reflection cavity mirror; a laser resonant cavity is formed between the total reflection cavity mirror and the output cavity mirror, and the first laser medium and the second laser medium respectively provide gain to generate lasers of corresponding wavelengths, and the two laser wavelengths do not compete with each other.

[0006] The present invention is further configured as: The laser wavelengths generated by the first laser medium and the second laser medium are different, and each only consumes the inverted population of its own laser medium. The gain is provided by each laser medium, and the dual wavelengths are generated by an independent gain channel, and there is no gain competition in the output dual-wavelength laser.

[0007] The present invention is further configured as: The first laser medium and the second laser medium are composed of the same active ions doped in different matrix materials, and the laser wavelengths generated by the corresponding energy level transitions of the active ions are different, and there is no corresponding energy level sub-transition to generate another wavelength. The dual-wavelength laser is generated by the transition between the same group of energy levels of the active ions in the laser medium.

[0008] The present invention is further configured as: The first laser medium and the second laser medium are a combination of Nd:YLF crystal and Nd:YVO 4 crystal, a combination of Nd:YLF crystal and Nd:YAG crystal, a combination of Nd:YLF crystal and Nd:YAP crystal, or a combination of Nd:Y 2 O 3 crystal and Nd:YAG crystal.

[0009] The present invention is further configured as: The first laser medium is placed close to the total reflection cavity mirror, and the absorption of the first laser medium for the pump light is between 30% and 50%; the second laser medium is placed according to the first laser medium, and the absorption of the second laser medium for the pump light is above 70%.

[0010] The present invention is further configured as: The first laser medium and the second laser medium are processed into thin sheet shapes or short rod shapes, and the length is between 0.5 mm and 5 mm.

[0011] The present invention is further configured as: The total reflection cavity mirror is coated with a dielectric film with high reflectivity for the lasers of the two wavelengths, and the reflectivity is greater than 99%. The output cavity mirror is coated with a dielectric film with partial reflection for the lasers of the two wavelengths, and the reflectivity is between 60% and 98%, and the corresponding wavelengths are determined by each laser medium.

[0012] The present invention is further configured such that: the pump source is a semiconductor laser, and the emission wavelength is determined according to the absorption wavelength of the laser medium, and a semiconductor laser in the 808 nm or 880 nm band is adopted.

[0013] The present invention is further configured such that: a Q-switch is arranged between the laser medium two and the output mirror, and pulsed dual-wavelength laser is generated by Q-switching.

[0014] The present invention is further configured such that: the intensity ratio of the two laser wavelengths is achieved by longitudinally adjusting the position of the output port of the pump source, and longitudinally adjusting the position of the output port of the pump source realizes the relative position adjustment of the waist formed by the focused pump light through the coupling system between the laser medium one and the laser medium two, so as to adjust the size of the pump spot in the two laser media, and adjust the pump power density in the laser medium, so as to achieve the purpose of adjusting the dual-wavelength threshold and the dual-wavelength intensity ratio.

[0015] The beneficial effects of the present invention are: compared with the prior art, the structure design of the present invention is reasonable. The dual-wavelength laser of the present invention uses two laser media to respectively provide gain to generate lasers corresponding to the wavelengths, and the two wavelengths do not compete with each other, overcoming the power fluctuation problem caused by the gain competition of different wavelengths sharing the gain channel in the traditional same laser medium, so the output dual-wavelength ratio and power are stable; the two laser media share the pump source and the coupling system and oscillate in the same resonant cavity, so the whole system is a laser, and the dual wavelengths are output in the same optical path. Compared with obtaining two-wavelength lasers by using two lasers, the beam combining device is omitted, and the structure is more compact, the manufacturing cost is low, the system is stable, the operation is convenient and the practicability is good.

[0016] The present invention will be further described below in conjunction with the specification drawings and specific embodiments. Description of the Drawings

[0017] Figure 1 It is a schematic structural diagram of an embodiment of the present invention. Specific Embodiments

[0018] In the description of this embodiment, it should be noted that, when terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", "front", "rear", etc. appear, the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore, it cannot be understood as a limitation to the present invention. In addition, when terms such as "first", "second", "third" appear, they are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0019] See Figure 1, A common cavity independent gain channel dual-wavelength laser disclosed by the present invention includes a pump source 1, a coupling system 2, a total reflection cavity mirror 3, a gain medium pair, and an output cavity mirror 7 arranged in sequence along the optical path. The gain medium pair includes a first laser medium 4 and a second laser medium 5, and the first laser medium 4 and the second laser medium 5 are placed in a compact series type; the light output by the pump source 1 forms a focused light beam through the coupling system 2, and the light beam is incident on the gain medium pair through the total reflection cavity mirror 3; a laser resonator is formed between the total reflection cavity mirror 3 and the output cavity mirror 7, and the first laser medium 4 and the second laser medium 5 respectively provide gain to generate lasers of corresponding wavelengths, and the two laser wavelengths do not compete with each other.

[0020] The laser wavelengths respectively generated by the first laser medium 4 and the second laser medium 5 are different, and each only consumes the inverted population of its own laser medium. The gain is provided by its own laser medium, and a dual wavelength is generated through an independent gain channel. There is no gain competition in the output dual-wavelength laser.

[0021] The first laser medium 4 and the second laser medium 5 are composed of the same active ions doped in different matrix materials, and the laser wavelengths generated by the corresponding energy level transitions of the active ions are different, and there is no corresponding energy level sub-transition to generate another wavelength. The dual-wavelength laser is generated by the transition between the same group of energy levels of the active ions in the laser medium.

[0022] The first laser medium 4 and the second laser medium 5 are a combination of Nd:YLF crystal and Nd:YVO 4 crystal, a combination of Nd:YLF crystal and Nd:YAG crystal, a combination of Nd:YLF crystal and Nd:YAP crystal, or a combination of Nd:Y 2 O 3 crystal and Nd:YAG crystal, etc. The crystal combinations output dual wavelengths as shown in the table:

[0023] Crystal combination <![CDATA[Nd:YLF / Nd:YVO 4 > Nd:YLF / Nd:YAP <![CDATA[Nd:Y 2 O 3 / Nd:YAG]]> Nd:YLF / Nd:YAG Output of dual wavelengths 1047 / 1064 nm 1047 / 1080 nm 1080 / 1064 nm 1047 / 1064 nm

[0024] The first laser medium 4 is placed close to the total reflection cavity mirror 3, and the absorption of the first laser medium 4 for the pump light is between 30% and 50%; the second laser medium 5 is placed following the first laser medium 4, and the absorption of the second laser medium 5 for the pump light is above 70%.

[0025] The first laser medium 4 and the second laser medium 5 are processed into thin sheet shapes or short rod shapes, and the length is between 0.5 mm and 5 mm.

[0026] The total reflection cavity mirror 3 is coated with a dielectric film with high reflectivity for the lasers of the two wavelengths, and the reflectivity is greater than 99%. The output cavity mirror 7 is coated with a dielectric film with partial reflectivity for the lasers of the two wavelengths, and the reflectivity is between 60% and 98%. The corresponding wavelengths are determined by each laser medium.

[0027] The pump source 1 is a semiconductor laser, and the emission wavelength is determined according to the absorption wavelength of the laser medium. A semiconductor laser in the 808 nm or 880 nm band is used.

[0028] In practical applications, a pump source, a coupling system, a total reflection cavity mirror, a gain medium pair, and an output cavity mirror are sequentially arranged in the optical path of the laser. The gain medium pair is composed of laser medium one (Nd:YLF crystal) and laser medium two (Nd:YVO 4 crystal) placed in a compact series. The light output by the pump source forms a focused beam through the mirror coupling system and is incident on the gain medium pair through the total reflection cavity mirror; a laser resonance cavity is formed between the total reflection mirror and the output mirror. The laser medium one (Nd:YLF crystal) and the laser medium two (Nd:YVO 4 crystal) are doped with the same active ion Nd 3+ and have different compositions of matrix materials (YLF and YVO 4 ), and the laser wavelengths generated by the corresponding energy level transitions 4 F 3 / 2 - 4 I 11 / 2 are different, which are 1047 nm and 1064 nm respectively, so as to form a dual wavelength. The 1047 nm and 1064 nm dual wavelength lasers output by the laser are generated by the transitions between the same group of energy levels 3+ of the laser medium Nd 4 F 3 / 2 - 4 I 11 / 2 and, due to the energy level difference of Nd 3+ doped in different matrix materials (YLF and YVO 4 ), there is no gain competition between them.

[0029] The laser medium one is placed close to the total reflection cavity mirror. When processing, the crystal length needs to be considered to ensure that the absorption of the pump light by the entire laser medium pair cannot be too large, so as to ensure that there is enough pump light to excite the laser medium two to generate the laser of the corresponding wavelength. Preferably, the absorption of the Nd:YLF crystal for the pump light is about 50%.

[0030] The Nd:YVO 4 crystal is placed according to the Nd:YLF crystal. When processing, try to ensure full absorption of the pump light, so as to make full use of the pump light. Preferably, it is recommended that the absorption of the Nd:YVO 4 crystal for the pump light is about 90%.

[0031] Preferably, the laser medium one and the laser medium two are processed into thin sheet or short rod shapes, and the length is preferably between 0.5 mm and 5 mm. Preferably, Nd:YLF and Nd:YVO 4The crystal lengths are 2.5 mm and 5 mm respectively.

[0032] The total reflection mirror is coated with a dielectric film that highly reflects lasers with wavelengths of 1047 nm and 1064 nm, and the reflectivity is greater than 99.8%. The output mirror is coated with a dielectric film that partially reflects lasers with wavelengths of 1047 and 1064 nm, and the reflectivity is 90%.

[0033] The pump source is a semiconductor laser, and its emission wavelength is generally determined according to the absorption wavelength of the laser medium. In this embodiment, a semiconductor laser in the 808 nm band is used.

[0034] Principle of the common cavity independent gain channel dual-wavelength laser: The pump source outputs pump light in the 808 nm band, which forms a focused beam through the coupling system and enters the gain medium pair through the total reflection mirror. The first laser gain medium (Nd:YLF crystal) first absorbs part of the pump light, reaches the population inversion condition for forming laser, and forms its corresponding 1047 nm wavelength laser to oscillate between the resonant cavity composed of the total reflection mirror and the output mirror. The remaining part of the pump light after being absorbed by the first laser medium (Nd:YLF crystal) enters the second laser medium (Nd:YVO 4 crystal) and is absorbed, which also enables the second laser medium (Nd:YVO 4 crystal) to reach the population inversion condition, and also forms its corresponding 1064 nm wavelength laser to oscillate between the resonant cavity composed of the total reflection mirror and the output mirror. Since the laser wavelengths generated by the two laser media are different, they only consume the inverted population of their respective laser media and obtain gain from their respective laser media, that is, the independent gain channels generate the dual wavelengths of 1047 nm and 1064 nm. The output dual-wavelength laser has no gain competition, so it has good stability. Because the lasers generated by the two laser media share the same resonant cavity composed of the total reflection mirror and the output mirror, the generated light paths also overlap.

[0035] In addition, a Q-switch 6 is provided between the second laser medium 5 and the output mirror 7 to generate pulsed dual-wavelength laser by Q-switching. The intensity ratio of the two laser wavelengths can be achieved by longitudinally adjusting the position of the pump source output port; and longitudinally adjusting the position of the pump source output port can realize the relative position adjustment of the beam waist formed by the focused pump light through the coupling system between the first laser medium (Nd:YLF crystal) and the second laser medium (Nd:YVO 4 crystal), so as to adjust the size of the pump spot in the two laser media, thereby adjusting the pump power density in the laser medium and achieving the purpose of adjusting the dual-wavelength threshold and the dual-wavelength intensity ratio. When the position of the focused beam waist moves towards the Nd:YVO 4 crystal, the intensity of the 1064 nm wavelength increases relative to the intensity of 1047 nm, and vice versa.

[0036] Advantages: The dual-wavelength laser of the present invention uses two laser media to provide gain respectively to generate lasers of corresponding wavelengths. The two wavelengths do not compete with each other, overcoming the problem of power fluctuation caused by gain competition when different wavelengths share the gain channel in the traditional same laser medium. Therefore, the output ratio and power of the dual wavelengths are stable. The two laser media share a pump source and a coupling system and oscillate in the same resonant cavity. So the whole system is a single laser, and the dual wavelengths are output in the same optical path. Compared with obtaining two-wavelength lasers by using two lasers, the beam combining device is omitted, and the system is more compact, stable and lower in cost. Moreover, the intensity ratio of the two wavelengths of the realized dual-wavelength laser can be conveniently adjusted, which is also difficult to achieve for dual-wavelength lasers on the current market.

[0037] The specific description of the present invention in the above embodiments is only for further illustration of the present invention, and should not be construed as a limitation on the protection scope of the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the content of the above invention fall within the protection scope of the present invention.

Claims

1. A common cavity independent gain channel dual wavelength laser, characterized in that: The invention comprises a pump source (1), a coupling system (2), a total reflection cavity mirror (3), a gain medium pair and an output cavity mirror (7) which are arranged in sequence along an optical path; the gain medium pair comprises a laser medium 1 (4) and a laser medium 2 (5); the laser medium 1 (4) and the laser medium 2 (5) are arranged in a compact series; light output by the pump source (1) forms a focused light beam through the coupling system (2); the light beam enters the gain medium pair through the total reflection cavity mirror (3); a laser resonant cavity is formed between the total reflection cavity mirror (3) and the output cavity mirror (7); the laser medium 1 (4) and the laser medium 2 (5) respectively provide gain to generate lasers of corresponding wavelengths, and the two laser wavelengths do not compete with each other.

2. A common cavity independent gain channel dual wavelength laser according to claim 1, characterized in that: The laser wavelengths generated by the laser medium 1 (4) and the laser medium 2 (5) are different. Both consume only the inversion particle number of their respective laser media. Gain is provided by their respective laser media. Independent gain channels generate dual wavelengths. There is no gain competition in the output dual-wavelength lasers.

3. A common cavity independent gain channel dual wavelength laser according to claim 2, characterized in that: The laser medium 1 (4) and the laser medium 2 (5) are made of materials doped with the same activated ions and different matrix materials, and the laser wavelengths generated by the corresponding activated ion energy level transitions are different. There are no corresponding energy level sub-transitions to each other to produce another wavelength. The dual-wavelength laser is generated by the transition between the same group of energy levels of the laser medium activated ions.

4. The common cavity independent gain channel dual wavelength laser according to claim 3, characterized in that: The laser medium 1 (4) and the laser medium 2 (5) are a combination of Nd:YLF crystal and Nd:YVO4 crystal, a combination of Nd:YLF crystal and Nd:YAG crystal, a combination of Nd:YLF crystal and Nd:YAP crystal, or a combination of Nd:Y2O3 crystal and Nd:YAG crystal.

5. The common cavity independent gain channel dual wavelength laser according to claim 4, characterized in that: The laser medium 1 (4) is placed close to the total reflective cavity mirror (5), and the absorption of the pump light by the laser medium 1 is between 30% and 50%; the laser medium 2 is placed next to the laser medium 1, and the absorption of the pump light by the laser medium 2 is above 70%.

6. The common cavity independent gain channel dual wavelength laser according to claim 5, characterized in that: The laser medium 1 (4) and the laser medium 2 (5) are processed into thin sheets or short rods with a length between 0.5 mm and 5 mm.

7. The common cavity independent gain channel dual wavelength laser according to claim 6, characterized in that: The total reflection cavity mirror (3) is coated with a dielectric film that is highly reflective to two wavelength lasers, with a reflectivity greater than 99%, and the output cavity mirror (7) is coated with a dielectric film that is partially reflective to two wavelength lasers, with a reflectivity between 60% and 98%, and the corresponding wavelength is determined by each laser medium.

8. The common cavity independent gain channel dual wavelength laser according to claim 7, characterized in that: The pump source (1) is a semiconductor laser, the emission wavelength is determined according to the absorption wavelength of the laser medium, and a semiconductor laser in the 808nm or 880nm band is used.

9. A common cavity independent gain channel dual wavelength laser according to claim 1 or 8, characterized in that: A Q switch (6) is provided between the second laser medium (5) and the output cavity mirror (7), and pulsed dual-wavelength laser is generated by Q switching.

10. A common cavity independent gain channel dual wavelength laser according to claim 1 or 8, characterized in that: The intensity ratio of the two laser wavelengths is achieved by longitudinally adjusting the position of the pump source output port, and longitudinally adjusting the position of the pump source output port realizes the relative position adjustment between the laser medium 1 and the laser medium 2 of the beam waist formed by focusing the pump light through the coupling system, thereby adjusting the size of the pump light spot in the two laser media and adjusting the pump power density in the laser medium, thereby achieving the purpose of adjusting the dual-wavelength threshold and the dual-wavelength intensity ratio.

Images