CN202997296U - Double KTP frequency-multiplication and electro-optic Q-switching integration device - Google Patents

Abstract

The utility model relates to a dual KTP frequency doubling and electro-optic Q-switching integrated device, which includes a shell, electrodes, and electro-optic crystals. The electro-optic crystals include two low-conductivity, non-critical temperature phase-matched KTP crystals arranged in sequence from left to right. , rotated 90° in sequence; gold-plated on the upper and lower energized surfaces of the first KTP crystal, gold-plated on the front and rear energized surfaces of the second KTP crystal; gold-plated on the upper energized surface of the first KTP crystal and The gold-plated film on the front energized surface of the second KTP crystal draws the gold wire and is connected to the positive electrode; the gold-plated film on the lower energized surface of the first KTP crystal and the gold-plated film on the back energized surface of the second KTP crystal lead out the gold wire and connect to Negative electrode; when the electro-optical Q-switching function of the device adopts the back-voltage working mode. The utility model realizes two functions of frequency doubling and electro-optic Q-switching, and at the same time eliminates the walk-off angle, compensates the static birefringence phase delay, and eliminates the influence on the phase matching angle when the crystal is pressurized.

Description

A dual KTP frequency doubling and electro-optical Q-switching integrated device

Technical field :

The invention relates to an electro-optic Q-switching device, in particular to a device capable of realizing frequency multiplication nonlinear effect and electro-optic Q-switching in a laser.

Background technique:

KTP-like crystals have large effective nonlinear coefficients and good electro-optical properties, so the research on using this type of crystals to develop optical frequency doubling and electro-optic multiplexing devices has aroused great interest. In 1994, Japan's T. Takunori et al. used a 1×3×5mm ³ KTP crystal to achieve simultaneous frequency doubling and Q-switching for the 1064nm laser output by Nd:YVO ₄ . When the repetition frequency is 100Hz, the modulated 532nm pulse laser output with a pulse width of 18ns and a peak power of 15.4W (Takunori Taira, Takao Kobayashi. Q-switching and frequency doubling of solid-state laser by a single intracavity KTP crystal [J] , IEEE. J. Quantum Eleronies, 1994, 30(3): 800-804). In 1995, they achieved a green light output with a peak power of 230W (Takunori Taira, Takao Kobayashi. Intraeavity frequency doubling and Q-switching in diode laser pumped Nd:YVO ₄ laser [J], Applied Optics 1995, 34(21): 4298-4301). In 1997, Yao Jianquan and others calculated the matching angle and applied voltage when KTP crystal frequency doubling Q-switching (J. Q. Yao, X. W. Sun, H. S. Kwok. Analysis of simultaneous Q-switching and frequency doubling in KTP [J], Journal of modern Optics, 1997, 44(5): 997-1004). In 2000, Chen Fei and others used KTP crystals of 2×4×10mm ³ to achieve TEM ₀₀ mode output with a pulse width of 12ns and a peak power of 762W when the repetition frequency was 1kHz, the l/4 voltage was 647V, and the pump power was 1W. And realized the device, the whole volume is only half the size of color film (Chen Fei, Huo Yujing, new electro-optic Q-switched intracavity green laser [J], Chinese Engineering Science, 2000, 2(4): 39-42). In the above schemes, KTP is used as the frequency doubling and electro-optic Q-switching device, and a KTP crystal is used, which is cut according to the phase matching angle, and the pressurized working method is used when electro-optic Q-switching in the laser. However, there is a static birefringent phase delay in the KTP crystal, which affects the closing effect of electro-optic Q-switching; and cut according to the phase matching angle at room temperature, there is a walk-off angle during frequency doubling, which affects the frequency doubling conversion efficiency and the beam quality of the output light ;Using pressurized working mode, the electro-optic Q-switching and frequency doubling effect occur at the same time, and the voltage changes the crystal refractive index, thereby affecting the frequency doubling effect.

Invention content :

The invention aims at the deficiencies of the prior art, and provides a double KTP frequency multiplication and electro-optical Q-switching integrated device which has no walk-off angle and can eliminate static birefringence phase delay.

The solution adopted by the present invention to achieve the above object is: a dual KTP frequency multiplication and electro-optic Q-switching integrated device, including a shell, electrodes, and electro-optic crystals. The electro-optic crystals include two non-critical temperature phase-matching cut KTP crystals, from left to right Set the first KTP crystal and the second KTP crystal rotated 90° relative to the first KTP crystal in sequence; the upper energized surface of the first KTP crystal is plated with gold film, the lower energized surface is plated with gold film, and the first KTP crystal is opposite to the first KTP crystal. The second KTP crystal rotated by 90° has a gold-plated front surface and a gold-plated rear surface; gold is drawn from the gold-plated upper surface of the first KTP crystal and the gold-plated front surface of the second KTP crystal. The wire is connected to the positive electrode; the gold wire is drawn from the gold-plated film on the lower energized surface of the first KTP crystal and the gold-plated film on the rear energized surface of the second KTP crystal, and connected to the negative electrode; when the device is electro-optical Q-switched, it uses back-voltage work Way.

As a further improvement of the utility model, the first KTP crystal and the KTP crystal rotated 90° relative to the first KTP crystal are low-conductivity KTP crystals.

As a further improvement of the utility model, the first KTP crystal and the KTP crystal rotated 90° relative to the first KTP crystal are controlled by temperature to realize frequency doubling phase matching.

As a further improvement of the utility model, the light-transmitting surfaces of the first KTP crystal and the KTP crystal rotated 90° relative to the first KTP crystal are square.

As a further improvement of the utility model, the first KTP crystal and the inner optical surface of the KTP crystal rotated 90° relative to the first KTP crystal are connected with insulating and transparent optical glue, and the outer optical surface is coated with 1064nm and 532nm two-color AR coating.

As a further improvement of the utility model, the first KTP crystal and the KTP crystal rotated 90° relative to the first KTP crystal are placed in sequence, and the inner and outer smooth surfaces are coated with 1064nm and 532nm double-color anti-reflection coatings.

The present invention realizes above object principle and is:

The cutting angle of frequency doubling non-critical phase matching of KTP crystal is q=90°, j=0°, KTP crystal can realize frequency doubling non-critical phase matching at 80°C, so the control temperature of the crystal should be kept at 80°C. When non-critical phase-matching cut, KTP crystal frequency doubling has no walk-off angle, therefore, this kind of cut crystal eliminates the walk-off angle.

The phase delay generated when polarized light passes through a single KTP crystal is:

In the above formula, the first term Γs is the phase delay caused by natural birefringence, which has nothing to do with the applied electric field; the second term Γ _E is the phase delay caused by the applied electric field.

If an identical KTP crystal rotated by 90° is connected in series after this KTP crystal, the phase delay generated when the polarized light passes through the series-connected KTP crystal is:

At this point, the natural birefringence ( _nz - n _x ) term is compensated. Therefore, the structure we designed can well compensate the natural birefringence of KTP crystals. According to the above derivation, the phase delay of two KTP crystals connected in series with a relative rotation of 90° is:

相位延迟所需的半波电压是单块KTP电光Q开关的1/2。 V is the voltage applied along the z direction, from which the required half-wave voltage Vπ can be calculated. The working method of electro-optic Q-switching adopts back-pressure type, so that electro-optic Q-switching and frequency doubling are separated in time, and the influence on the phase matching angle when the crystal is pressurized can be ignored. In addition, two KTP crystals are optically connected in series and electrically connected in parallel, resulting in

The half-wave voltage required for phase delay is 1/2 of that of a single KTP electro-optical Q switch.

Assuming that the side length of the light-passing surface is d=4mm, the length of the light-passing surface is L, and when the value of d/L is different, the corresponding half-wave voltage is shown in the table below:

Table 1 Half-wave voltage required for different aspect ratios

Beneficial effects of the present invention:

The present invention uses KTP as the frequency doubling and electro-optic Q switching device, and one device simultaneously realizes two functions of frequency doubling and electro-optic Q-switching. The KTP crystal is cut according to non-critical phase matching, eliminating the walk-off angle; two KTP crystals are relatively rotated by 90° ° placement eliminates the static phase delay caused by static birefringence, and adopts the depressurization working method to eliminate the influence on the phase matching angle when the crystal is pressurized.

Description of drawings :

Figure 1. Schematic diagram of the device where KTP crystals are connected by optical glue

Figure 2. Schematic diagram of the device with antireflection coating coated on the light-passing surface of the KTP crystal

Graphic description:

(1) First open KTP crystal;

(2) The second KTP crystal rotated 90° relative to the first KTP crystal;

(3) Gold-plated film on the upper energized surface of the first KTP crystal;

(4) The lower conductive surface of the first KTP crystal is plated with gold film;

(5) The front electrified surface of the second KTP crystal is plated with gold;

(6) Gold-plated film on the rear electrified surface of the second KTP crystal;

(7) Positive electrode;

(8) Negative electrode.

Specific implementation methods :

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

Embodiment 1 Referring to Figure 1, a dual KTP frequency doubling and electro-optic Q-switching integrated device includes a housing, electrodes, and an electro-optic crystal. The electro-optic crystal includes two non-critical temperature phase-matching cut KTP crystals, and the first one is arranged in turn from left to right. A KTP crystal 1 and a second KTP crystal 2 rotated 90° relative to the first KTP crystal 1; the upper energized surface of the first KTP crystal 1 is plated with gold film 3, and the lower energized surface is plated with gold film 4. A gold-plated film 5 on the front energized surface of the second KTP crystal 2 placed by a KTP crystal rotated 90°, and a gold-plated film 6 on the rear energized surface; from the gold-plated film 3 on the upper energized surface of the first KTP crystal and the gold-plated film 3 of the second KTP crystal Gold wires are drawn from the gold-plated film 5 on the front energized surface and connected to the positive electrode 7; gold wires are drawn from the gold-plated film 4 on the lower energized surface of the first KTP crystal and the gold-plated film 6 on the rear energized surface of the second KTP crystal, connected to the negative electrode 8.

The first KTP crystal 1 and the KTP crystal 2 placed at a 90° rotation relative to the first KTP crystal are low-conductivity KTP crystals.

The first KTP crystal 1 and the KTP crystal 2 rotated by 90° relative to the first KTP crystal are controlled by temperature to achieve frequency doubling phase matching; the temperature is 80°C.

The light-transmitting surfaces of the first KTP crystal 1 and the KTP crystal 2 rotated 90° relative to the first KTP crystal are square.

The first KTP crystal 1 and the KTP crystal 2 rotated 90° relative to the first KTP crystal are connected to each other with insulating and transparent optical adhesive, and the outer transparent surface is coated with 1064nm and 532nm two-color anti-reflection coatings.

Embodiment 2 is basically the same as Embodiment 1, except that the first KTP crystal 1 and the KTP crystal 2 rotated 90° relative to the first KTP crystal are placed in sequence, with an interval of about 1mm in the middle, and the inner light surface and the outer light The smooth surface is coated with 1064nm and 532nm dual-color anti-reflection coatings.

The invention is used in the laser as a Q-switching and frequency doubling device of the laser. The 1064nm laser passes through the KTP crystal, and the nonlinear effect of frequency doubling occurs, and the 532nm laser is emitted, and the pulsed laser with high peak power is obtained through electro-optic Q-switching. When the electro-optic Q-switching works, it adopts the devoltage working mode to eliminate the influence on the phase matching angle when the crystal is pressurized. The boundary temperature of the crystal is controlled by a temperature-controlled furnace.

Claims (5)

1. two KTP frequencys multiplication and electric-optically Q-switched integrated device, comprise shell, electrode, electrooptic crystal, it is characterized in that:

Electrooptic crystal comprises the ktp crystal of two non-critical temperature phase matched cuttings, from left to right sets gradually the ktp crystal (2) of first ktp crystal (1) and the placement of relative first ktp crystal (1) half-twist;

At the gold-plated film of upper energising face (3) of first ktp crystal (1), the gold-plated film of lower energising face (4), the gold-plated film of front energising face (5) of second ktp crystal (2) of placing at relative first ktp crystal half-twist, the gold-plated film of rear energising face (6); Draw gold thread from the gold-plated film of upper energising face (3) of first ktp crystal (1) and the gold-plated film of front energising face (5) of second ktp crystal (2), be connected to positive electrode (7); Draw gold thread from the gold-plated film of lower energising face (4) of first ktp crystal (1) and the gold-plated film of rear energising face (6) of second ktp crystal (2), be connected to negative electrode (8);

Device electro-optical is transferred Q to do the used time employing and is moved back the pressure working method.

2. a kind of pair of KTP frequency multiplication according to claim 1 and electric-optically Q-switched integrated device is characterized in that:

First ktp crystal (1) is the ktp crystal of low conductivity with the ktp crystal (2) that relative first ktp crystal half-twist placed.

3. a kind of pair of KTP frequency multiplication according to claim 1 and electric-optically Q-switched integrated device is characterized in that:

First ktp crystal (1) is square with the logical light face of the ktp crystal (2) that relative first ktp crystal half-twist placed.

4. a kind of pair of KTP frequency multiplication according to claim 1 and electric-optically Q-switched integrated device is characterized in that:

First ktp crystal (1) interior logical light face relative with the ktp crystal (2) that relative first ktp crystal half-twist placed is connected with the optical cement of insulation transparent, and outer logical light face plates 1064nm and the double-colored anti-reflection film of 532nm.

5. a kind of pair of KTP frequency multiplication according to claim 1 and electric-optically Q-switched integrated device is characterized in that:

First ktp crystal (1) placed successively with the ktp crystal (2) that relative first ktp crystal half-twist placed, interior logical light face and outer logical light face plating 1064nm and the double-colored anti-reflection film of 532nm.

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