Dual-wavelength laser based on polarization beam splitting

Abstract

The dual-wavelength laser is structurally characterized in that a quarter-wave plate (2), a DKDP crystal electro-optical Q-switch (3) and a first polarization splitting prism (4) are sequentially arranged on the light reflecting side of a total reflection mirror (1), and an LD side pumping Nd: YAG crystal module (5) is arranged on the light reflecting side of the first polarization splitting prism (4); a second polarization splitting prism (6) is arranged on the other side of the LD side pumping Nd: YAG crystal module (5), an electro-optical Q switch (7), a third polarization splitting prism (8) and a 1064nm output mirror (9) are sequentially arranged on the light reflecting side of the second polarization splitting prism (6), and a 45-degree reflector (10) and a KTP crystal (11) are sequentially arranged on the light reflecting side of the third polarization splitting prism (8). The device is stable in output, high in electro-optical conversion efficiency, high in switching speed, simple to debug, low in failure rate, safe and reliable.

Description

Technical Field

[0001] The invention belongs to the field of laser technology and relates to a dual-wavelength laser based on polarization splitting. Background Art

[0002] Dual-wavelength laser refers to a single laser that can output two wavelengths of laser at the same time. Compared with the dual-wavelength laser achieved by combining two independent lasers, it has the advantages of compact structure, simple and reliable. Dual-wavelength lasers can provide versatility and have important applications and development prospects in the fields of biomedicine, laser communication, laser detection, etc. For example, in biomedicine, different organs in the human body have higher absorption peaks for specific wavelengths. Different wavelength lasers can be used to treat or cut specific organs, making the medical process more precise and controllable. In laser communication, the use of dual-wavelength lasers to achieve signal transmission can effectively improve the security of information. One of the wavelengths of laser can be used as an encryption laser to increase the reliability of laser communication. At present, the common methods that can achieve all-solid-state dual-wavelength lasers mainly include: using a single laser crystal stimulated radiation to achieve dual-wavelength laser generation, using two different laser crystals stimulated radiation to achieve dual-wavelength laser generation, and using a single-wavelength laser pumped optical parametric oscillator (OPO) to achieve dual-wavelength laser generation.

[0003] Common dual-wavelength lasers mostly use a single optical path, and dual-wavelength output is achieved by coating the lens with films of different wavelengths and different transmittances. A single optical path allows two wavelengths of laser to be generated simultaneously. When a specific wavelength laser is used, the other wavelength laser is wasted, and the laser power and laser efficiency are affected, making it impossible to achieve accurate single wavelength output.

[0004] Common dual-wavelength lasers usually switch wavelengths by switching in and out of optical devices. Optical devices will inevitably have deviations during the switching process, and it is impossible to ensure that the optical path is always in the optimal output state, which reduces the stability of laser output. Summary of the invention

[0005] (I) Purpose of the invention

[0006] The purpose of the present invention is to provide a dual-wavelength laser based on polarization splitting, to achieve accurate single-wavelength output and to improve the stability of laser output.

[0007] (II) Technical solution

[0008] In order to solve the above technical problems, the present invention provides a dual-wavelength laser based on polarization splitting, which comprises: a total reflector 1, a quarter wave plate 2, a DKDP crystal electro-optical Q-switch 3, a first polarization splitter prism 4, an LD side-pumped Nd:YAG crystal module 5, a second polarization splitter prism 6, an electro-optical Q-switch 7, a third polarization splitter prism 8, a 1064nm output mirror 9, a 45° reflector 10, and a KTP crystal 11; the quarter wave plate 2, the DKDP crystal electro-optical Q-switch 3, the first polarization splitter prism 4, the LD side-pumped Nd:YAG crystal module 5, the second polarization splitter prism 6, the electro-optical Q-switch 7, the third polarization splitter prism 8, the 1064nm output mirror 9, the 45° reflector 10, and the ... A KDP crystal electro-optical Q-switch 3, a first polarization beam splitter prism 4, an LD side-pumped Nd:YAG crystal module 5 is arranged on the reflective side of the first polarization beam splitter prism 4, a second polarization beam splitter prism 6 is arranged on the other side of the LD side-pumped Nd:YAG crystal module 5, an electro-optical Q switch 7, a third polarization beam splitter prism 8, and a 1064nm output mirror 9 are arranged in sequence on the reflective side of the second polarization beam splitter prism 6, a 45° reflector 10 and a KTP crystal 11 are arranged in sequence on the reflective side of the third polarization beam splitter prism 8.

[0009] Among them, a λ / 4 voltage is applied to the DKDP crystal electro-optical Q-switching switch 3 to produce a Pockels effect, so that the vibration direction of the linearly polarized light passing through the DKDP crystal electro-optical Q-switching switch 3 changes by π / 2. Under the joint action of the quarter-wave plate 2, the polarization direction of the light in the resonant cavity is not changed.

[0010] The voltage on the DKDP crystal electro-optical Q-switch 3 is disconnected, and the vibration direction of the linearly polarized light passing through the DKDP crystal electro-optical Q-switch 3 remains unchanged. Under the action of the quarter-wave plate 2, the polarization direction of the light in the resonant cavity is changed.

[0011] Among them, when there is no voltage on the DKDP crystal electro-optical Q-switching switch 3, the laser does not oscillate in the cavity, and the resonant cavity is in a low Q value state; when external excitation is applied, when voltage is instantaneously applied to the crystal, the laser oscillates in the resonant cavity, and the resonant cavity is in a high Q value state, generating a laser giant pulse.

[0012] The LD side-pumped Nd:YAG crystal module 5 includes an LD array and a Nd:YAG crystal. The LD array pumps the Nd:YAG crystal to generate fundamental frequency light with a central wavelength of 1064 nm.

[0013] The LD side-pumped Nd:YAG crystal module 5 generates non-linear polarized light, and the first polarization beam splitter prism 4 splits the incident non-linear polarized light into two perpendicular linear polarized light beams, P polarized light and S polarized light. The P polarized light passes through, and the S polarized light is reflected at an angle of 90 degrees.

[0014] The KTP crystal 11 is coated front and back, the light inlet facing the 45° reflector 10 is coated with a film that makes the light with a central wavelength of 1064nm highly transparent and the light with a central wavelength of 1570nm highly reflective, and the light outlet on the other side is coated with a film that makes the light with a central wavelength of 1064nm highly reflective.

[0015] Among them, when no voltage is applied to the DKDP crystal electro-optical Q-switch 3 and the electro-optical Q-switch 7, the Nd:YAG crystal module 5 is converted into s-light by the first polarization beam splitter prism 4 and the second polarization beam splitter prism 6, is converted into circularly polarized light by the 1 / 4 wave plate 2, and is then reflected back into the cavity by the total reflection mirror 1. The circularly polarized light is converted into linearly polarized light by the 1 / 4 wave plate 2, and the polarization direction is changed by 90 degrees to become p-light, which exits the cavity through the first polarization beam splitter prism 4.

[0016] Among them, when a 1 / 4 wave voltage is added to the DKDP crystal electro-optical Q-switch 3, the effects of the DKDP crystal electro-optical Q-switch 3 and the 1 / 4 wave plate 2 cancel each other out, and the oscillation in the resonant cavity is vertically polarized s light. When a 1 / 2 wave voltage is added to the electro-optical Q switch 7, the vertically polarized s light oscillating in the cavity is converted into horizontally polarized p light by the electro-optical Q switch 7, and 1064nm fundamental frequency light is output through the output mirror 9.

[0017] Among them, when the DKDP crystal electro-optical Q-switch 3 is added with a 1 / 4 wave voltage, the effects of the DKDP crystal electro-optical Q-switch 3 and the 1 / 4 wave plate cancel each other, and the vertically polarized light s light oscillates in the resonant cavity. The electro-optical Q switch 7 is not applied with a voltage, and the vertically polarized light oscillating in the cavity is reflected by the third polarization beam splitter prism 8 to the 45° reflector 10, and then transmitted to the KTP crystal 11, so that the light with a central wavelength of 1570nm partially passes through the dielectric film with a transmittance of 40%; nonlinear optical frequency conversion is realized through the KTP crystal 11, and the fundamental frequency light with a central wavelength of 1064nm is used to generate a laser with a central wavelength of 1570nm.

[0018] (III) Beneficial effects

[0019] The dual-wavelength laser based on polarization splitting provided by the above technical solution has stable output, high electro-optical conversion efficiency, fast switching speed, simple debugging, low failure rate, and safety and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of a dual-wavelength laser based on polarization splitting according to an embodiment of the present invention. DETAILED DESCRIPTION

[0021] In order to make the purpose, content and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below in conjunction with the drawings and examples.

[0022] Reference Figure 1As shown, the dual-wavelength laser based on polarization splitting in this embodiment includes a total reflector 1, a quarter wave plate 2, a DKDP crystal electro-optical Q switch 3, a first polarization splitter prism 4, an LD side-pumped Nd:YAG crystal module 5, a second polarization splitter prism 6, an electro-optical Q switch 7, a third polarization splitter prism 8, a 1064nm output mirror 9, a 45° reflector 10, and a KTP crystal 11; the quarter wave plate 2, the DKDP crystal electro-optical Q switch 3, the first polarization splitter prism 4, the LD side-pumped Nd:YAG crystal module 5, the second polarization splitter prism 6, the electro-optical Q switch 7, the third polarization splitter prism 8, the 1064nm output mirror 9, the 45° reflector 10, and the KTP crystal 11; the reflective side of the total reflector 1 is arranged in sequence. A Q-switched switch 3, a first polarization beam splitter prism 4, an LD side-pumped Nd:YAG crystal module 5 is arranged on the reflective side of the first polarization beam splitter prism 4, a second polarization beam splitter prism 6 is arranged on the other side of the LD side-pumped Nd:YAG crystal module 5, an electro-optical Q switch 7, a third polarization beam splitter prism 8, and a 1064nm output mirror 9 are arranged in sequence on the reflective side of the second polarization beam splitter prism 6, a 45° reflector 10 and a KTP crystal 11 are arranged in sequence on the reflective side of the third polarization beam splitter prism 8.

[0023] The working principle of the dual-wavelength laser is as follows: the electro-optical Q-switch 3 realizes the modulation of the laser loss through the electro-optical Q-switching effect. When a λ / 4 voltage is applied to the DKDP crystal electro-optical Q-switch 3, the Pockels effect is generated, so that the vibration direction of the linear polarized light passing through the DKDP crystal electro-optical Q-switch 3 changes by π / 2. Under the joint action of the quarter-wave plate 2, the polarization direction of the light in the resonant cavity is not changed. When the voltage on the DKDP crystal electro-optical Q-switch 3 is disconnected, the vibration direction of the linear polarized light passing through the DKDP crystal electro-optical Q-switch 3 remains unchanged. Under the action of the quarter-wave plate 2, the polarization direction of the light in the resonant cavity is changed. Therefore, when there is no voltage on the DKDP crystal electro-optical Q-switch 3, the laser cannot form oscillation in the cavity, and the resonant cavity is in a low Q value state. Due to external excitation, the number of upper energy level particles increases rapidly. When a voltage is suddenly applied to the crystal, the laser forms oscillation in the cavity. At this time, the resonant cavity is in a high Q value state, thereby generating a laser giant pulse.

[0024] The LD side-pumped Nd:YAG crystal module 5 comprises an LD array and a Nd:YAG crystal. The LD array pumps the Nd:YAG crystal to generate fundamental frequency light with a central wavelength of 1064 nm.

[0025] The LD side-pumped Nd:YAG crystal module 5 generates non-linear polarized light. The first polarization beam splitter prism 4 splits the incident non-linear polarized light into two perpendicular linear polarized light beams, P polarized light and S polarized light. The P polarized light passes through, and the S polarized light is reflected at an angle of 90 degrees.

[0026] When no voltage is applied to the DKDP crystal electro-optical Q-switch 3 and the electro-optical Q-switch 7, the Nd:YAG crystal module 5 is transformed into s-light by the first polarization beam splitter prism 4 and the second polarization beam splitter prism 6, and is transformed into circularly polarized light by the 1 / 4 wave plate 2, and then reflected back into the cavity by the total reflection mirror 1. The circularly polarized light is transformed into linearly polarized light by the 1 / 4 wave plate 2, but the polarization direction is changed by 90 degrees to become p-light, and then exits the cavity through the first polarization beam splitter prism 4. The resonant cavity is in a high loss and low Q value state, and the number of reversed particles in the pump module continues to accumulate.

[0027] When a 1 / 4 wave voltage is applied to the DKDP crystal electro-optic Q switch 3, the effects of the DKDP crystal electro-optic Q switch 3 and the 1 / 4 wave plate 2 cancel each other out, and the oscillation in the resonant cavity is vertically polarized s light. When a 1 / 2 wave voltage is applied to the electro-optic Q switch 7, the vertically polarized s light oscillating in the cavity is converted into horizontally polarized p light by the electro-optic Q switch 7, and 1064nm fundamental frequency light is output through the output mirror 9.

[0028] When a 1 / 4 wave voltage is applied to the DKDP crystal electro-optical Q-switch 3, the effects of the DKDP crystal electro-optical Q-switch 3 and the 1 / 4 wave plate cancel each other, and vertically polarized light s light oscillates in the resonant cavity. No voltage is applied to the electro-optical Q switch 7, and the vertically polarized light oscillating in the cavity is reflected by the third polarization beam splitter 8 to the 45° reflector 10, and then transmitted to the KTP crystal 11. The KTP crystal 11 is coated on the front and back. The light inlet facing the 45° reflector 10 is coated with a film that makes the light with a central wavelength of 1064nm highly transparent and the light with a central wavelength of 1570nm highly reflective, and the light outlet on the other side is coated with a high-reflective film for the central wavelength of 1064nm and a dielectric film that partially transmits the light with a central wavelength of 1570nm, with a transmittance of 40%. Nonlinear optical frequency conversion is realized by the KTP crystal 11, and the fundamental frequency light with a central wavelength of 1064nm is used to generate a laser with a central wavelength of 1570nm.

[0029] It can be seen from the above technical scheme that the dual-wavelength laser of the present invention adopts dual Q-switched crystals, a single 1 / 4 wave plate, and three polarization beam splitters to achieve 1064nm / 1570nm dual-wavelength switching output; when switching wavelengths, the wavelength switching is achieved by simply applying voltage through the Q-switched crystal, with fast switching speed, stable output, and long service life.

[0030] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A dual-wavelength laser based on polarization splitting, characterized in that: include: A total reflection mirror (1), a quarter wave plate (2), a DKDP crystal electro-optical Q-switching switch (3), a first polarization beam splitter prism (4), an LD side-pumped Nd:YAG crystal module (5), a second polarization beam splitter prism (6), an electro-optical Q-switch (7), a third polarization beam splitter prism (8), a 1064 nm output mirror (9), a 45° reflection mirror (10), and a KTP crystal (11); a quarter wave plate (2), a DKDP crystal electro-optical Q-switching switch (3), a first polarization beam splitter prism (4), a LD side-pumped Nd:YAG crystal module (5), a second polarization beam splitter prism (6), an electro-optical Q-switch (7), a third polarization beam splitter prism (8), a 1064 nm output mirror (9), a 45° reflection mirror (10), and a KTP crystal (11); the reflecting side of the total reflection mirror (1) is sequentially arranged with a quarter wave plate (2), a DKDP crystal electro-optical Q-switching switch (3), a first polarization beam splitter prism A polarization beam splitter prism (4) is provided, an LD side-pumped Nd:YAG crystal module (5) is arranged on the reflective side of the first polarization beam splitter prism (4), a second polarization beam splitter prism (6) is arranged on the other side of the LD side-pumped Nd:YAG crystal module (5), an electro-optical Q switch (7), a third polarization beam splitter prism (8), and a 1064 nm output mirror (9) are arranged in sequence on the reflective side of the second polarization beam splitter prism (6), and a 45° reflector (10) and a KTP crystal (11) are arranged in sequence on the reflective side of the third polarization beam splitter prism (8).

2. The dual-wavelength laser based on polarization splitting as claimed in claim 1, characterized in that: A λ / 4 voltage is applied to the DKDP crystal electro-optical Q-switching switch (3) to generate a Pockels effect, so that the vibration direction of the linearly polarized light passing through the DKDP crystal electro-optical Q-switching switch (3) changes by π / 2, and under the joint action of a quarter wave plate (2), the polarization direction of the light in the resonant cavity is not changed.

3. The dual-wavelength laser based on polarization splitting as claimed in claim 2, characterized in that: The voltage on the DKDP crystal electro-optical Q-switching switch (3) is disconnected, the vibration direction of the linearly polarized light passing through the DKDP crystal electro-optical Q-switching switch (3) remains unchanged, and the polarization direction of the light in the resonant cavity is changed under the action of the quarter-wave plate (2).

4. The dual-wavelength laser based on polarization splitting as claimed in claim 3, characterized in that: When there is no voltage on the DKDP crystal electro-optical Q-switching switch (3), the laser does not oscillate in the cavity, and the resonant cavity is in a low Q value state; when external excitation is applied, when voltage is instantaneously applied to the crystal, the laser oscillates in the resonant cavity, and the resonant cavity is in a high Q value state, generating a laser giant pulse.

5. The dual-wavelength laser based on polarization splitting as claimed in claim 4, characterized in that: The LD side-pumped Nd:YAG crystal module (5) comprises an LD array and a Nd:YAG crystal. The LD array pumps the Nd:YAG crystal to generate fundamental frequency light with a central wavelength of 1064 nm.

6. The dual-wavelength laser based on polarization splitting as claimed in claim 5, characterized in that: The LD side-pumps the Nd:YAG crystal module (5) to generate non-linear polarized light. The first polarization beam splitter (4) splits the incident non-linear polarized light into two perpendicular linear polarized light beams, P polarized light and S polarized light. The P polarized light passes through, and the S polarized light is reflected at an angle of 90 degrees.

7. The dual-wavelength laser based on polarization splitting as claimed in claim 6, characterized in that: The KTP crystal (11) is coated on the front and back, the light inlet facing the 45° reflector (10) is coated with a film that makes the light with a central wavelength of 1064nm highly transparent and makes the light with a central wavelength of 1570nm highly reflective, and the light outlet on the other side is coated with a film that makes the light with a central wavelength of 1064nm highly reflective.

8. The dual-wavelength laser based on polarization splitting as claimed in claim 7, characterized in that: When no voltage is applied to the DKDP crystal electro-optical Q-switching switch (3) and the electro-optical Q-switch (7), the Nd:YAG crystal module (5) is transformed into s-light by the first polarization beam splitter prism (4) and the second polarization beam splitter prism (6), is transformed into circularly polarized light by the quarter wave plate (2), and is then reflected back into the cavity by the total reflection mirror (1). The circularly polarized light is then transformed into linearly polarized light by the quarter wave plate (2), and its polarization direction is changed by 90 degrees to become p-light, which is then emitted out of the cavity by the first polarization beam splitter prism (4).

9. The dual-wavelength laser based on polarization splitting as claimed in claim 8, characterized in that: When a 1 / 4 wave voltage is applied to the DKDP crystal electro-optic Q-switching switch (3), the effects of the DKDP crystal electro-optic Q-switching switch (3) and the 1 / 4 wave plate (2) cancel each other out, and the oscillation in the resonant cavity is vertically polarized s light. When a 1 / 2 wave voltage is applied to the electro-optic Q switch (7), the vertically polarized s light oscillating in the cavity is converted into horizontally polarized p light by the electro-optic Q switch (7), and 1064 nm fundamental frequency light is output through the output mirror (9).

10. The dual-wavelength laser based on polarization splitting as claimed in claim 9, characterized in that: When a 1 / 4 wave voltage is applied to the DKDP crystal electro-optical Q-switching switch (3), the effects of the DKDP crystal electro-optical Q-switching switch (3) and the 1 / 4 wave plate cancel each other out, and vertically polarized light s light oscillates in the resonant cavity. When no voltage is applied to the electro-optical Q-switch (7), the vertically polarized light oscillating in the cavity is reflected by the third polarization beam splitter (8) to the 45° reflector (10), and then transmitted to the KTP crystal (11), so that part of the light with a central wavelength of 1570 nm passes through the dielectric film with a transmittance of 40%. Nonlinear optical frequency conversion is realized through the KTP crystal (11), and a laser with a central wavelength of 1570 nm is generated by using the fundamental frequency light with a central wavelength of 1064 nm.

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