CN207663191U - A kind of terahertz pulse generation device before the inclined wave based on transmission grating - Google Patents
A kind of terahertz pulse generation device before the inclined wave based on transmission grating Download PDFInfo
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- CN207663191U CN207663191U CN201721347710.7U CN201721347710U CN207663191U CN 207663191 U CN207663191 U CN 207663191U CN 201721347710 U CN201721347710 U CN 201721347710U CN 207663191 U CN207663191 U CN 207663191U
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- lithium niobate
- terahertz pulse
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- transmission grating
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Abstract
The utility model provides the terahertz pulse generation device before a kind of inclined wave based on transmission grating, and described device includes the femto-second laser being arranged in order, transmission grating, half-wave plate, imaging system and lithium niobate transmitting crystal；The pumping femtosecond laser of the femto-second laser transmitting emits diffraction by the transmission grating；The half-wave plate receives the positive/negative first-order diffraction light of the transmission grating；After half-wave plate changes the polarization direction of pumping femtosecond laser, lithium niobate transmitting crystal is incident to by imaging system, terahertz pulse radiation is generated in the lithium niobate transmitting crystal.The positive/negative first-order diffraction light of transmission grating and incident light angular separation are small, are more prone to during light path is built, and can realize the precision tuning of grating angle, obtain better terahertz pulse emission effciency.
Description
Technical field
The utility model is related to optical technical field, more particularly, to before a kind of inclined wave based on transmission grating too
Hertz pulse generating device.
Background technology
Terahertz (THz) radiation is commonly referred to as electromagnetic wave from 0.1~10THz, wave band microwave and far infrared it
Between.Due to specific position of the Terahertz frequency on electromagnetic spectrum so that the high-energy light source of this frequency range lacks very much.High energy
The terahertz emission source of amount can be divided into synchrotron radiation THz source and the small-sized THz source of Table top type according to the size of device.It is synchronous
The THz source of radiation can generate the terahertz pulse of hundred micro- burnt magnitudes, but such large-scale plant is costly and operation is high
It is expensive.The high field terahertz emission source of Table top type is mainly driven by pulsed femtosecond laser, can be divided into according to the difference of producing method：
Optical rectification, photoconducting antenna, air plasma, laser target shooting etc..
It is up to the present to be considered the most effective side for realizing miniaturization high energy terahertz pulse source to tilt wave front technology
Formula.To realize the inclination of wave front of exciting light so that there are one on the direction of propagation of its group velocity and the direction of propagation of phase velocity
A specific angle, traditional mode can be realized by porjection type ladder lens, the trapezoidal mirror of reflection-type, reflection-type grating.Due to
Ladder lens involve great expense and requirement to reflected light path is very high, are built in optimization process in light path, there are certain difficulties, make
It obtains reflection-type grating and receives favor.
Realize that tilting wave front technology has the following problems using reflection-type grating：(1) difficulty that light path is built；Using inclining
It is very high that oblique wave front technology realizes that the generation of high energy terahertz pulse radiation requires the precision of light path, this just enters grating
The accuracy of firing angle and angle of reflection proposes very high requirement, increases the difficulty that light path is built；(2) THz wave generation efficiency
Optimization is difficult；In using the experimentation for tilting wave front technology generation high energy THz wave, the orientation optimization of grating is to entire
Test most important, to cause to come out from grating when optimizing the angle of grating using reflection-type grating diffraction
The direction of propagation of light changes correspondingly, and then subsequent optical element is caused to deviate, need to be using consistent regulative mode come real
The alignment and adjusting of existing light path so that the efficiency for optimizing terahertz emission is more difficult；(3) increase of cost；In order to realize essence
Accurate optical path adjusting, reflection-type grating generally require the expensive grating rotating platform and adjusting bracket of configuration in use, greatly
Ground improves the cost of experiment.
Utility model content
The utility model provide a kind of one kind for overcoming the above problem or solving the above problems at least partly be based on it is saturating
The terahertz pulse generation device for penetrating grating slope wavefront solves and realizes high energy too using inclination wave front technology in the prior art
Light path builds difficulty, is difficult to the problem adjusted and cost is excessively high when hertz impulse radiation.
One side according to the present utility model provides a kind of terahertz pulse generation device, including is arranged in order winged
Second laser, transmission grating, half-wave plate, imaging system and lithium niobate transmitting crystal；The pumping of the femto-second laser transmitting flies
Second laser passes through the transmission grating and emits diffraction；The half-wave plate receives the positive/negative first-order diffraction light of the transmission grating；Through
After half-wave plate changes the polarization direction of pumping femtosecond laser, lithium niobate transmitting crystal is incident to by imaging system, in the niobium
Terahertz pulse radiation is generated in sour lithium transmitting crystal.
Preferably, the lithium niobate transmitting crystal is the triangular prism niobium that one jiao is 62~63 degree in gore
Sour crystalline lithium.
Preferably, the lithium niobate transmitting crystal is lithium columbate crystal integrated structure, including base angle is 62~63 degree,
The lithium niobate crystal chip that the isosceles triangle prism lithium columbate crystal and a thickness that apex angle is 54~56 degree are 1~5mm, it is described
Lithium niobate crystal chip is completely covered by by the method for optical contact where the isosceles triangle prism lithium columbate crystal bottom edge
On cylinder；
Wherein, three cylinders of the isosceles triangle prism lithium columbate crystal are handled by optical polish.
Preferably, magnesia of the lithium niobate transmitting crystal doped with 5~6.2mol%.
Preferably, when the pumping femtosecond laser is incident to the lithium niobate transmitting crystal, femtosecond laser is pumped
The crystal axis parallel of polarization direction and the lithium niobate crystal chip.
Preferably, the imaging system is single lens, double lens combination or cylindrical lens combination.
Preferably, the imaging magnification of the imaging system is 0.3~0.6 times.
Preferably, the femto-second laser, transmission grating, half-wave plate, imaging system and lithium niobate transmitting crystal point
It is not installed on a workbench by the holder being adjusted by rotation.
Preferably, further including speculum and collimating mirror, the speculum is set to the transmitting light of the femto-second laser
On the road, the collimating mirror is set on the reflected light path of the speculum, and the collimating mirror is used to pump femtosecond laser collimation
Introduce transmission grating.
The utility model proposes the terahertz pulse generation devices and method before a kind of inclined wave based on transmission grating, use
Transmission grating realizes the inclination of wave front of exciting light, and the Exciting incidence and angle of diffraction of transmission grating are calculated by realizing,
Exciting light is introduced into transmission grating by speculum, collimating mirror again, maximum energy is obtained using the positive/negative first-order diffraction of transmission grating
Amount, then traveled to exciting light on lithium niobate transmitting crystal by imaging system, realize the radiation of high energy terahertz pulse；Transmitted light
The positive/negative first-order diffraction light of grid and incident light angular separation are small, are more prone to during light path is built, and can realize light
The precision tuning of grid angle obtains better terahertz pulse emission effciency.
Description of the drawings
Fig. 1 is the terahertz pulse generation device structural schematic diagram according to the utility model embodiment；
Fig. 2 is the diffraction pattern schematic diagram according to the transmission grating of the utility model embodiment；
Fig. 3 is according to isosceles triangle prism lithium niobate crystal in the lithium columbate crystal integrated structure of the utility model embodiment
The structure chart of body design.
Specific implementation mode
With reference to the accompanying drawings and examples, specific embodiment of the present utility model is described in further detail.Below
Embodiment is not intended to limit the scope of the present invention for illustrating the utility model.
As shown in Figure 1, show a kind of terahertz pulse generation device in figure, including be arranged in order femto-second laser,
Transmission grating, half-wave plate, imaging system and lithium niobate transmitting crystal；The pumping femtosecond laser of the femto-second laser transmitting passes through
The transmission grating emits diffraction；The half-wave plate receives the positive/negative first-order diffraction light of the transmission grating；Change through half-wave plate
Behind the polarization direction for pumping femtosecond laser, lithium niobate transmitting crystal is incident to by imaging system, is emitted in the lithium niobate brilliant
Terahertz pulse radiation is generated in body.
As shown in Fig. 2, for the diffraction pattern of transmission grating, pass through the excitation of transmission grating computed in advance in the present embodiment
Angle of light and angle of diffraction, the positive/negative first-order diffraction light of selective transmission grating, the positive/negative first-order diffraction light of transmission grating with
Incident light angular separation is small, is more prone to during light path is built；It is obtained most using the positive/negative first-order diffraction of transmission grating
Big energy, then traveled to exciting light on lithium niobate transmitting crystal by imaging system, ensure the work to exciting light used in experiment
Make the diffraction that wavelength realizes peak efficiency, loses minimum exciting light energy.
In the present embodiment, lithium niobate transmitting crystal is the triangular prism niobic acid that one jiao is 62~63 degree in gore
Crystalline lithium, the length of side and thickness of crystal do not limit.
In the present embodiment, described as shown in figure 3, lithium columbate crystal integrated structure also can be used in lithium niobate transmitting crystal
Lithium columbate crystal integrated structure includes that base angle is 62~63 degree, the isosceles triangle rib that the Y-direction that apex angle is 54~56 degree is cut
The lithium niobate crystal chip that the Y-direction that column lithium columbate crystal and a thickness are 1~5mm is cut, the lithium niobate crystal chip pass through light
It learns on the cylinder where the method contacted is completely covered by the isosceles triangle prism lithium columbate crystal bottom edge；
Wherein, three cylinders of the isosceles triangle prism lithium columbate crystal are handled by optical polish.
Specifically, the lithium niobate isoceles triangle prismatic crystals cut along the Y-direction of crystal；The crystal is in XZ planes
Cutting mode be two 62.8 degree of base angles, 54.4 degree of apex angle isosceles triangle；Y-direction cutting lithium niobate prism be
The MgO doping concentrations of 6.0mol%.It is triangular structure.Three rectangular surfaces non-anti-reflection coateds.In crystal XZ planes
Two isosceles triangle faces without polishing, and for the three face light requirement optical polishings parallel with Y direction.The lithium niobate prismatic is brilliant
The effect of body is, by the inclined wavefront of incident laser by being successfully transferred to the lithium niobate crystal on piece of combination, and will produce
Biological exciting light energy after terahertz emission, which is successfully all-trans, to be shot out, for use in the generation of next stage terahertz emission,
Achieve the purpose that exciting light energy Reusability, to improve the energy conversion efficiency of terahertz emission.
In the plane of 54.4 degree of angle faces of the crystal, it need to be combined closely one piece of lithium niobate by the method for optical contact
A mode of cutting for chip, the chip is cut for Y-direction；The Z-direction of chip is parallel with the Y-axis of crystal；The size of chip has needed
Face where the isosceles triangle bottom edge of all standing lithium niobate prismatic crystals, and the Y of the X-axis of the chip and lithium niobate prismatic crystals
Axis is vertical.It can be smoothly transferred in lithium niobate crystal chip by the exciting light after lithium niobate prismatic crystals, it will not in the face of combination
Reflection loss is caused, it will not be to being damaged before inclined wave and so that high energy terahertz pulse can not generate.
In the present embodiment, the lithium niobate transmitting crystal is the triangular prism lithium niobate crystal cut along Z-direction
The lithium niobate crystal chip integrated structure of body or the triangular prism lithium columbate crystal and Y-direction cutting that cut along the Y direction.
In the present embodiment, magnesia of the lithium niobate transmitting crystal doped with 5~6.2mol%.
Using the above-mentioned lithium niobate transmitting crystal or crystal combination structure of the present embodiment, high-energy, large spot are swashed
It shines, overcomes the problems, such as that conventional crystal structure is unable to maintain that efficient terahertz emission, while special design to be emitted
THz wave be not present non-linear distortion the problem of, obtain better THz wave emission characteristics, be convenient for subsequent experimental application.
In the present embodiment, when the pumping femtosecond laser is incident to the lithium niobate transmitting crystal, femtosecond laser is pumped
Polarization direction and the lithium niobate crystal chip crystal axis parallel.
In the present embodiment, the imaging system is single lens, double lens combination or cylindrical lens combination.
By accurately calculating the incidence angle and the angle of diffraction of grating, the present embodiment utilizes a half-wave plate by the polarization direction of light
It is vertical and parallel with the optical axis direction of the lithium niobate crystal chip of binding from being horizontally diverted so that for chip integrated structure, to generate too
Hertz impulse radiation is located in bound chip, and in the lithium niobate crystal body of non-triangular cutting.Between grating and crystal at
Picture system is cylindrical lens pair 44, and imaging minification is 0.3-0.6 times.
In the present embodiment, the femto-second laser, transmission grating, half-wave plate, imaging system and lithium niobate transmitting crystal
It is installed on a workbench by the holder being adjusted by rotation respectively.By by transmission grating and follow-up imaging system and lithium niobate
Transmitting crystal is installed on a spinstand, it can be achieved that the precision tuning of grating angle, obtains better terahertz sources efficiency.
In the present embodiment, further include speculum and collimating mirror, transmitting of the speculum set on the femto-second laser
In light path, the collimating mirror is set on the reflected light path of the speculum, and the collimating mirror will be for that will pump femtosecond laser collimation
Introducing transmission grating.
A kind of terahertz pulse launching technique is additionally provided in the present embodiment, including：
Transmission grating diffraction is carried out to pumping femtosecond laser, the positive/negative first-order diffraction light of transmission grating is incident to half-wave
On piece is incident to imaging system after half-wave plate changes polarization direction, carries out diminution imaging；
The light beam reduced after being imaged is incident to lithium niobate transmitting crystal, Terahertz arteries and veins is generated in lithium niobate transmitting crystal
Punching radiation.
Wherein, the lithium niobate transmitting crystal is that cut into base angle be 62~63 degree, and apex angle is 54~56 degree of isosceles
The lithium niobate crystal chip that triangular prism lithium columbate crystal and a thickness are 1~5mm, the lithium niobate crystal chip are connect by optics
Tactile method is completely covered by the cylinder where the isosceles triangle prism lithium columbate crystal bottom edge；Wherein, the isosceles
Three cylinders of triangular prism lithium columbate crystal are handled by optical polish.
Wherein, the polarization direction when pumping femtosecond laser is incident on the lithium niobate transmitting crystal and the lithium niobate
The crystal axis parallel of chip.
The utility model proposes the terahertz pulse generation devices before a kind of inclined wave based on transmission grating, using transmitted light
Grid realize the inclination of wave front of exciting light, and the Exciting incidence and angle of diffraction of transmission grating are calculated by realizing, then will swash
It shines and transmission grating is introduced by speculum, collimating mirror, ceiling capacity is obtained using the positive/negative first-order diffraction of transmission grating, then
Exciting light is traveled on lithium niobate transmitting crystal by imaging system, realizes the radiation of high energy terahertz pulse；Transmission grating
Positive/negative first-order diffraction light and incident light angular separation are small, are more prone to during light path is built, and can realize grating angle
The precision tuning of degree obtains better terahertz pulse emission effciency.
Finally, the method for the utility model is only preferable embodiment, is not intended to limit the protection of the utility model
Range.Within the spirit and principle of the utility model, any modification, equivalent replacement, improvement and so on should be included in
Within the scope of protection of the utility model.
Claims (8)
1. a kind of terahertz pulse generation device, which is characterized in that including be arranged in order femto-second laser, transmission grating, half
Wave plate, imaging system and lithium niobate transmitting crystal；The pumping femtosecond laser of the femto-second laser transmitting passes through the transmitted light
Grid emit diffraction；The half-wave plate receives the positive/negative first-order diffraction light of the transmission grating；Change pumping femtosecond through half-wave plate to swash
Behind the polarization direction of light, lithium niobate transmitting crystal is incident to by imaging system, is generated too in the lithium niobate transmitting crystal
Hertz impulse radiation.
2. terahertz pulse generation device according to claim 1, which is characterized in that the lithium niobate transmitting crystal is three
The triangular prism lithium columbate crystal that one jiao is 62~63 degree in angled face.
3. terahertz pulse generation device according to claim 1, which is characterized in that the lithium niobate transmitting crystal is niobium
Sour crystalline lithium integrated structure, including base angle are 62~63 degree, the isosceles triangle prism lithium columbate crystal that apex angle is 54~56 degree
And the lithium niobate crystal chip that a thickness is 1~5mm, the lithium niobate crystal chip are completely covered by institute by the method for optical contact
It states on the cylinder where isosceles triangle prism lithium columbate crystal bottom edge；
Wherein, three cylinders of the isosceles triangle prism lithium columbate crystal are handled by optical polish.
4. terahertz pulse generation device according to claim 3, which is characterized in that the pumping femtosecond laser is incident to
When the lithium niobate transmitting crystal, the crystal axis parallel of the polarization direction and the lithium niobate crystal chip of femtosecond laser is pumped.
5. terahertz pulse generation device according to claim 1, which is characterized in that the imaging system is single saturating
Mirror, double lens combination or cylindrical lens combination.
6. terahertz pulse generation device according to claim 1, which is characterized in that the imaging magnification of the imaging system
It is 0.3~0.6 times.
7. terahertz pulse generation device according to claim 1, which is characterized in that the femto-second laser, transmitted light
Grid, half-wave plate, imaging system and lithium niobate transmitting crystal are installed to by adjustable holder on a workbench respectively.
8. terahertz pulse generation device according to claim 7, which is characterized in that further include speculum and collimating mirror,
The speculum is set in the transmitting light path of the femto-second laser, and the collimating mirror is set to the reflected light path of the speculum
On, the collimating mirror is used to pump the introducing transmission grating of femtosecond laser collimation.
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| CN201721347710.7U CN207663191U (en) | 2017-10-19 | 2017-10-19 | A kind of terahertz pulse generation device before the inclined wave based on transmission grating |
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| CN201721347710.7U CN207663191U (en) | 2017-10-19 | 2017-10-19 | A kind of terahertz pulse generation device before the inclined wave based on transmission grating |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107561818A (en) * | 2017-10-19 | 2018-01-09 | 北京航空航天大学 | Terahertz pulse generation device and method before a kind of inclined wave based on transmission grating |
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- 2017-10-19 CN CN201721347710.7U patent/CN207663191U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107561818A (en) * | 2017-10-19 | 2018-01-09 | 北京航空航天大学 | Terahertz pulse generation device and method before a kind of inclined wave based on transmission grating |
| CN107561818B (en) * | 2017-10-19 | 2023-09-26 | 北京航空航天大学 | Terahertz pulse generation device and method based on transmission grating inclined wavefront |
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