WO2007079661A1

WO2007079661A1 - A Nd:LuVO4 LASER HAVING A WAVELENGTH OF 916nm

Info

Publication number: WO2007079661A1
Application number: PCT/CN2006/003798
Authority: WO
Inventors: Zhiguo Zhang; Zhiyi Wei; Ling Zhang; Chunyu Zhang; Huaijin Zhang; Jiyang Wang
Original assignee: Institute Of Physics, Chinese Academy Of Sciences; Shandong University
Priority date: 2006-01-09
Filing date: 2006-12-31
Publication date: 2007-07-19
Also published as: CN101000997A

Abstract

A Nd:LuVO4 laser having a wavelength of 916nm includes a pump source (1), a optical coupling system (2) and a laser resonator. The laser resonator comprises at least two cavity mirrors (3, 6) and a laser gain medium (4) between the two cavity mirrors (3, 6). The laser gain medium (4) is Nd:LuVO4 crystal, and the pump source (1) pumps the laser gain medium (4) through the optical coupling system (2). The Nd:LuVO4 laser can obtain 458nm deep blue laser after frequency doubling.

Description

A Nd:LuV0 ₄ laser with a wavelength of 916 nm

The present invention relates to a laser device, and more particularly to a Nd:LuV0 ₄ (ytterbium-doped yttrium vanadate) laser having a wavelength of 916 nm. Background technique

Blue lasers have very important application prospects in high-density optical storage, ultrashort pulse, digital video technology, spectroscopy, laser medicine, laser large-screen display, marine military applications and underwater resource detection.

One of the current effective methods for generating high-power blue lasers is to directly generate a blue laser output using a laser of about 900 nm. As disclosed in Document 1: "Chin. Phys. Lett. 20 (2003) 1064", the prior art has successfully utilized Nd:YAG crystals to directly multiply the 946 nm laser to produce a high power 473 nm blue laser output.

The skilled person has found that in the laser large-screen display, in order to make the chromaticity closer to natural light, thereby effectively achieving the balance of the ternary color, it is expected to obtain a dark blue laser shorter than 473 nm. In recent years, important progress has been made in the study of vanadate laser crystals. Wherein due to the Nd: YV0 ₄ and Nd: GdV0 ₄ crystals appear, have been successfully used Nd: YV0 ₄ and Nd: GdV0 ₄ crystal fundamental frequency are 914 nm and 912 nm laser direct frequency doubling of 457 nm and 456 The output of the nm dark blue laser is disclosed in the product of Melles Griot, USA, and in Document 2: "Opt. Coranun. 205 (2002) 361".

Recently, people have successfully developed a new member in the vanadate family, which is: 1 ^ ^ 0 ₄ crystal. Nd: LuV0 ₄ In addition to the conventional crystal vanadate crystal having good laser characteristics, studies have shown that Nd: LuV0 ₄ crystal with respect to the Nd: YV0 ^ B Nd: GdV0 4 crystal has greater absorption and stimulated emission cross section Thus, it is a laser crystal with a wider application prospect, as disclosed in Document 3: "Opt. Materials 26 (2004) 319" and Document 4: "Appl. Opt. 44 (2005) 7439". The fundamental frequency laser output of 1. 06 um and 1. 34 um was obtained using a Nd: LuV0 ₄ crystal.

It is expected that a new wavelength (916 nm) laser can be built using the Nd: LuV0 ₄ crystal, so that with this new laser, another deep blue laser source can be obtained by frequency doubling. Summary of the invention

It is an object of the present invention to provide a 1«1^0 ₄ laser capable of generating a new laser wavelength of 916 nm; This new type of laser produces a new deep blue laser wavelength output after frequency doubling.

In order to achieve the above object, the present invention adopts the following technical solutions.

A wavelength of 916 nm: ^^0 ₄ laser, comprising a pump source, an optical coupling system, a laser cavity; the laser cavity is composed of at least two laser endoscopes and a laser gain medium placed between the laser end mirrors The laser gain medium is a Nd: V0 ₄ crystal, and the pump source is pumped by the optical coupling system.

Further, wherein the first end mirror of the laser serves as a laser cavity input end mirror, the input end mirror combines the laser end mirror and the laser gain medium by coating on one end surface of the laser gain medium The other end of the laser gain medium is coated with an anti-reflection film; or, the input end mirror adopts a separate cavity mirror coating as an input end mirror, and both ends of the laser gain medium are coated with an anti-reflection film. The output coupling mirror is also coated to suppress the laser excitation of the _/2 - ⁴ 1 _11/2 and ⁴ F _3/2 - ⁴ 1 _13/2 lasers, resulting in ⁴ F _3/2 - ⁴ I _{9/ 2} high-efficiency laser operation of the 916nm laser at the energy level transition.

Further, the pump source adopts an end face or a side pumping manner to the laser gain medium.

Further, when the laser cavity is directly coated on the pump end face of the laser gain medium as an input cavity mirror or a separate input cavity mirror is used to form the laser cavity input end mirror, the coating parameters are:

(a) For the 808 nm transmittance T 90%, for the 916 nm transmittance R ^ 99. 9%, for the 1. 06 um transmittance T 90%, for the 1. 34 um transmittance T 90 %;

(b) When using the side pumping method: For the 916 nm reflectance R 99.9%, for 1. 06um transmittance T ^90%, for 1. 34um transmittance T ^90%;

As the laser gain medium: the output end of the 1 ^ ¥ 0 ₄ crystal is plated with an antireflection film for 916 nm, 1. 06 um, 1. 34;

The transmittance of the second end mirror of the laser as the output end mirror of the laser cavity is: (a) when the output of the laser is 916 nm: for the 916 nm transmittance T is 0. 05% - 10%, for 1. 06 um transmittance T 90%, for 1. 34um transmittance T 90%; (b) when outputting 458nm laser: for 916 into the reflectivity R 99. 9%, for 1. 06um transmittance T 90%, for 1. 34um through The 过 rate is 90%, and the high transmittance is 458 nm.

Further, the coating parameter of the second end mirror of the laser as the output end mirror of the laser cavity is 95% transmittance at 458 nm when outputting the 458 ran laser.

Further, the laser cavity is a linear cavity or a folded cavity structure.

Further, the laser cavity further includes an intracavity function component, and the intracavity function component includes a Q-switching component, a mode-locking component, and a frequency doubling component. Further, the Q-switching component is an active Q-switching component or a passive passive Q-switching component to implement a Q-switching operation; the Clamping component is an active clamping component or a passive clamping component to implement a mode-locking operation; The crystal is a lithium triborate (LB0), barium metaborate (BB0), barium borate (BiB0), or potassium citrate (KNb0 ₃ ) crystal, which achieves a frequency-doubled output.

Further, the pump source is an end-pumped LD Bar (Laser Diode Bar, LD Bar for short) fiber-coupled semiconductor laser, or an LD Bar beam-shaping semiconductor laser, or an LD single-tube laser; or, the pump source It is a side-pumped single LD Bar array laser, or multiple LD Bar array lasers.

Further, the laser gain medium is a sheet or a single rod Nd:LuV0 ₄ crystal or a composite rod Nd:LuV0 ₄ crystal.

Further, the composite rod Nd _: LuV0 ₄ crystal is made of Nd: LuV0 ₄ crystal, and the laser crystal is diffusion bonded to the undoped YAG or LuV0 ₄ crystal at both ends.

Further, a cooling device is further included for cooling the laser gain medium, and the cooling device can be adjusted at a temperature of 1 to 20 ° C according to different operating conditions, and the temperature control accuracy is better than ± 1 ° C.

Further, the cooling device is a water cooling device, or a TEC (Thermoelectric cooling, TEC for short) cooling device, or a water-cooled and air-cooled mixed cooling device.

Further, a selection device for controlling the quality of the beam is further included in the laser cavity.

Further, the temperature control device for controlling the temperature of the frequency doubling crystal is controlled by a different frequency doubling crystal, and the temperature control accuracy is better than ±0. 5 ^e C.

The beneficial effects of the invention are:

The invention utilizes the laser crystal to realize the characteristics of laser operation at the ⁴ F _3/2 - ₂ energy level transition, adopts the Nd _: LuV0 ₄ laser crystal, and successfully suppresses the ⁴ F _3/ by the reasonable membrane design of the resonant cavity mirror. ₂ - ⁴ 1 „ _/2 and n~% laser operation, the operation of the 916nm laser under the ⁴ F _3/2 _ ⁴ I _9/2 energy level transition was obtained. By selecting the intracavity functional elements, the continuous laser operation of 916 nm was obtained. 916 pulsed laser operation and 458 nm deep blue laser operation by frequency doubling.

Figure 1 is a schematic view showing the structure of Embodiments 1 and 3 of the present invention;

Fig. 2 is a schematic view showing the structure of a second embodiment of the present invention.

Reference mark - 1. Diode pump source 2. Optical coupling system 3. Laser cavity input end mirror 4. Laser gain medium 5. In-cavity functional element 6. Laser cavity output end mirror embodiment

The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

Referring to Figure 1, a Nd:LuV0 ₄ fundamental (916 nm) and doubled (458 nm) laser was fabricated using a fiber-coupled semiconductor laser as the end-pump source.

As shown in FIG. 1 , the pump source 1 is a 25 W fiber-coupled semiconductor laser having an operating wavelength of 808 nm, a core diameter of 200, and a numerical aperture of 0.22. The pump source 1 and the optical coupling system 2 are optically coupled and optically coupled. The focused spot of the system 2 is approximately 240 _{Um in} diameter and is incident on the end face of the laser gain medium 4 for pumping; the laser gain medium 4 is 0.5 at. % Nd ion doped Nd: LuV0 ₄ crystal, the size of which is 3 X 3 X 2 mm ³ ; The laser gain medium 4 is cooled by a cooling device. This embodiment uses a heat sink water cooling device (not shown) whose temperature is controlled at 6 ^fl C; the pump end face of the laser gain medium 4 Direct coating, so that the first end mirror 3 as the laser cavity input end mirror and the laser gain medium 4 are combined into one, the coating parameters are: for the 916 nm reflectivity R 99.9%, such as the reflectivity R = 99.9%; for 808 nm transmittance T=90%, for 1. 06 um and 1.34um transmittance T=90%; the non-pump end of laser gain medium 4 is plated with 916 ηηκ 1. 06 um and 1.34 um anti-reflection film; laser as a laser output mirror at a fundamental frequency of 916 nm laser output The second end mirror 6 is a flat concave mirror having a radius of curvature of 100 ,, and the coating requirements are: for a transmittance of 916 nm T-3. 6%, for a transmittance of 1. 06 um T = 90%, for 1 34um transmittance T=90%; For the frequency doubled laser output mode, the intracavity functional component 5 is placed in the laser cavity, and the intracavity functional component 5 in this embodiment is a LB0 frequency doubling crystal, and the two end faces of the frequency doubling crystal It is coated with an antireflection coating of 916 nm and 458 nm. The size of the frequency doubling crystal is 3 X 3 X 10 mm ³ , and it is cut according to the type I phase matching method. The cutting parameters are θ = 90 ^β , Φ = 21. 8 ° The frequency doubling crystal is controlled by a temperature control device, and the temperature is controlled at 6±0. 1 ° C _; the second laser end mirror 6 as a laser cavity output end mirror is a flat concave having a radius of curvature of 100 Mirror, the coating conditions are: 916 nm reflectivity R = 99.9%, for 1. 06um transmittance T = 90%, for 1. 34ura transmittance T = 90%. For high transmittance at 458 nm, the fundamental resonant cavity length is 18 mm, and the frequency doubling experimental cavity length is 40 mm.

A 900 mW 916 ran laser output and a 50 m double frequency 458 ran blue output were obtained using the apparatus of the present embodiment. Example 2:

According to Figure 2, a single LD Bar array laser was used as the side pump source to fabricate a Nd:LuV0 ₄ fundamental frequency (916 nm) laser.

As shown in Figure 2, the pump source 1 is a 40 W single LD Bar array laser with an operating wavelength of 808 nm. The spot size focused by the optical coupling system 2 is approximately 100 X 500 urn ² , and the pump source 1 and optics are shown. The coupling system 2 is integrated; the laser gain medium 4 is 0.2 at. % Nd ion doped Nd : LuV0 ₄ crystal, the size is 3 X 3 X 5 mm ³ ; the laser gain medium 4 is cooled by a cooling device In this embodiment, a heat sink water cooling device (not shown) is used, and the temperature is controlled at 6 ° C; the film is directly coated on the pump end surface of the laser gain medium 4, so that the laser as the input end mirror of the laser cavity is first. The end mirror 3 and the laser gain medium 4 are combined into one, and the coating parameters are: for the 916 nm reflectance R 99.9%, such as the reflectivity R = 99.9%; for the 808 nm transmittance T = 90%, For the 1. 06 um and 1.34 um transmittance T = 90%; the non-pump end of the laser gain medium 4 is plated with an antireflection coating of 916 nm and 1.06 um and 1.34 um; as a laser output The second laser end mirror 6 of the mirror is a flat concave mirror having a radius of curvature of 100 ram, and the coating condition is as follows: for 916 ran, the transmittance T = 3.6%, for 1. 06um transmittance T=90%, for 1. 34um transmittance T=90%; resonant cavity length is 18

A 916 nm laser output greater than 1 W was obtained using the apparatus of this example. Example 3:

Referring to Figure 1, a Nd : LuV0 ₄ fundamental frequency (916 nm) laser was fabricated using a single diode tube as the end pump source. As shown in Figure 1, pump source 1 is an 8 W single-tube semiconductor laser with an operating wavelength of 808 nm and an emission cross section of 150 X 1 um ² . The spot size after focusing by optical coupling system 2 is approximately 50 X 50 um ^{2 .} The laser gain medium 4 is 0.2 at at % Nd ion doped Nd :LuV0 ₄ crystal, the size of which is 3 X 3 X 4 mm ³ ; the laser gain medium 4 is cooled by a cooling device, and the embodiment uses heat a submersible cooling device (not shown) whose temperature is controlled at 6 ° C; directly coated on the pump end face of the laser gain medium 4, so that the first end mirror 3 and the laser gain of the laser as the laser cavity input end mirror The dielectric is 4 in two, and the coating parameters are: for 916 nm reflectance R 99. 9%, such as reflectance R = 99. 9%; for 808 nm transmittance T = 90%, for 1. 06 um and 1. 34um transmittance T=90°/. The non-pump end of the laser gain medium 4 is plated with an antireflection coating for 916 nm and 1.06 um and 1.34 um; the second laser end mirror 6 as a laser output mirror is flat with a radius of curvature of 100 mm The coating of the concave mirror is: T = 3. 6 ° / for the transmittance of 916 nm. , for 1 · 06um transmittance Τ = 90%, for 1. 34um transmittance Τ = 90%; resonant cavity length is 18 mm

A 200 mW 916 nm laser output was obtained using the apparatus of this example. Finally, it should be noted that the above embodiments are merely illustrative of the technical solutions of the present invention and not limiting. While the invention has been described in detail herein with reference to the embodiments of the embodiments of the present invention Within the scope of the claims.

Claims

Rights request

1. A 1 0 ₄ laser having a wavelength of 916 nm, comprising a pump source, an optical coupling system, and a laser cavity; wherein the laser cavity is composed of at least two laser endoscopes and a laser gain medium disposed between the laser end mirrors The composition is characterized in that the laser gain medium is a Nd: LuV0 ₄ crystal, and the pump source pumps the laser gain medium through an optical coupling system.

2. The Nd:LuV0 ₄ laser having a wavelength of 916 nm according to claim 1, wherein said first end mirror of said laser serves as a laser cavity input end mirror, and said input end mirror is passed through said laser gain medium Coating an end face such that the laser end mirror and the laser gain medium are combined into one, and the other end of the laser gain medium is coated with an anti-reflection film; or, the input end mirror adopts a separate cavity mirror coating as an input end mirror The laser gain medium has an anti-reflection film on both ends.

3. The Nd:LuV0 ₄ laser having a wavelength of 916 nm according to claim 1 or 2, wherein the pump source is an end-pumped LD Bar fiber coupled semiconductor laser or an LD Bar beam shaping semiconductor laser, or It is an LD single-tube laser; alternatively, the pump source is a side-pumped single LD Bar array laser or multiple LD Bar array lasers. .

4. The Nd:LuV0 ₄ laser having a wavelength of 916 nm according to claim 1, wherein the pumping end face of the laser gain medium is directly coated as an input cavity mirror or a separate input cavity mirror is used to make the When the laser cavity is input to the end mirror, the coating parameters are:

(a) When the end-pumping method is used, the transmittance of 808 nm is T 90%, the reflectance of 916 nm is R^99.9%, and the transmittance of 1.06um is T 90%, and the transmittance of 1.34um is Τ 90. %;

(b) When using the side pumping method: For the 916 nm reflectance R 99.9%, for 1. 06um transmittance T^90%, for 1. 34um transmittance T 90%;

The output end of the laser gain medium is plated with an antireflection film for 916 nm, 1. 06 um, 1. 34 um; the coating parameters of the second end mirror of the laser as the output end mirror of the laser cavity are: (a) at the output 916 η π laser Time: for 916 nm transmittance T is 0. 05% - 10%, for 1. 06um transmittance T 90%, for 1, 34um transmittance T 90%; (b) when outputting 458nm laser: for 916nm The reflectance R 99.9%, for 1. 06um transmittance T 90%, for 1. 34um transmittance Τ 90%, for 458 ran is 髙 transmittance.

5. Nd:LuV having a wavelength of 916 nm according to claim 4 (laser, characterized in that the coating parameter of the second end mirror of the laser as the output end mirror of the laser cavity is 458 mn when outputting a 458 nm laser. The rate is T 95%.

6. The Nd:V (laser) having a wavelength of 916ran according to claim 1, wherein the laser cavity further comprises an intracavity functional element, the intracavity functional element comprising a Q-switching component, a mode-locking component, and a frequency multiplication. The Q-switching component is an active Q-switching component or a passive passive Q-switching component; the clamping component is an active mode-locking component or a passive mode-locking component; and the frequency doubling crystal is lithium triborate, barium metaborate, boric acid Bismuth, or potassium citrate crystals.

7. The Nd:LuV (laser) having a wavelength of 916 nm according to claim 1, wherein the laser gain medium is a thin sheet or a single rod Nd: LuV0 ₄ crystal or a composite rod Nd: LuV0 ₄ crystal, the composite rod The Nd:LuV0 ₄ crystal is made of Nd:LuV0 ₄ crystal, and the laser crystal is diffusion bonded to the undoped YAG or LuV0 ₄ crystal at both ends.

8. The Nd:LuV0 ₄ laser having a wavelength of 916 nm according to claim 1, further comprising: a cooling device for cooling said laser gain medium, said cooling device having a temperature adjustable from 1 to 20 ^fl C, The temperature control accuracy is better than ±1 °C; the cooling device is a water cooling device, or a TEC cooling device, or a water-cooled and air-cooled mixed cooling device.

9. The Nd:LuV (laser) having a wavelength of 916 nm according to claim 1, characterized in that said laser cavity further comprises a mode selection element for controlling the quality of the beam.

10, according to the claim 1 wavelength of 916nm laser ₀₄ ^ 1, characterized in that, further comprising a temperature control device for frequency doubling crystal temperature control.

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