CN117996556A - Device for generating continuously tunable narrow-band laser in ultra-wide frequency spectrum - Google Patents
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Abstract
The invention discloses a device for generating continuous tunable narrow-band laser in ultra-wide frequency spectrum, which comprises: narrow-band laser pump sources such as nanoseconds, picoseconds, even femtoseconds and the like can be tuned; the controllable nonlinear frequency conversion module is composed of two semi-cylindrical prisms and a single nonlinear polarized crystal. By utilizing the novel combined frequency conversion module and the PPLN sample internal angle tuning scheme, the nonlinear polarization crystal is obliquely incident on the pumping light source to carry out the frequency multiplication process, and the high-efficiency continuous tunable second harmonic which covers the fundamental frequency light from 750nm to 4900nm approximately and outputs an extremely wide spectrum can be generated through a 1-10-order multi-order quasi-phase matching mechanism. The invention has the advantages of small device size, easy preparation and processing of the semi-cylindrical prism, simple light path, strong mobility and wide application; the generated tunable frequency doubling laser has the advantages of wide covered frequency spectrum range and high energy conversion efficiency. The invention can be widely applied to the technical fields of laser technology and nonlinear frequency conversion.
Description
Technical Field
The invention relates to the technical field of laser technology and nonlinear frequency conversion, in particular to a device for generating continuous tunable narrow-band laser in an extremely wide frequency spectrum.
Background
Because the wavelength generated by the laser is influenced by the energy level structure of the gain medium, a plurality of wavelengths cannot be directly generated, and along with the requirements of other wavelength light sources in practical application, the wavelength conversion technology is gradually paid attention to, and becomes an important research project in nonlinear optics, and the realization of nonlinear frequency conversion by using the quasi-phase matching technology becomes an effective way for widening the laser frequency. The narrow linewidth laser is widely applied to the fields of gravitational wave detection, laser radar, distributed sensing, high-speed coherent optical communication and the like in recent years, so that the generation of continuous tunable narrow-band laser in an extremely wide frequency spectrum has important significance.
Under the quasi-phase matching of a specific order, a single periodic polarized lithium niobate crystal can only provide a single inverted lattice vector to compensate the phase mismatch of the single periodic polarized lithium niobate crystal, and output the wavelength of a single specific frequency. When the nonlinear frequency conversion is not extended by an external method, it is necessary to increase the number of crystal blocks to provide a plurality of inverted lattice vectors required for the nonlinear frequency conversion. Currently, there are many tuning means including temperature tuning, electric field tuning, angle tuning, etc., however, temperature tuning has several problems including the requirement for high-precision temperature control equipment, the influence of temperature drift on wavelength stability, long response time for high-low temperature switching, and easy degradation of crystal lifetime at high temperatures. On the other hand, the combination of multiple tuning methods increases the complexity of the experimental operation and uncertainty of the analysis of the results. The electric field tuning technique can solve the above problems to some extent, but nevertheless, the application of a uniform electric field to PPLN crystals does not provide tuning. The electro-optic disturbance caused by the uniform electric field produces phase-matched variations of the nonlinear parametric interactions, but in symmetric crystals they cancel each other out and the periodic field penetrates only to a certain depth from the crystal surface. The incident angle is used as an alternative tuning method in quasi-phase matching, by changing the angle of the pump light directly entering the crystal end face from air, under the scheme of the quasi-phase matching, tunable narrow-band laser can be generated, when the external incident angle can be ideally regulated and controlled from 0-90 degrees, the angle of the actual pump light entering the lithium niobate crystal is extremely small as known by the Snell's refraction law, when the nonlinear effect of frequency multiplication occurs, the internal angle change is only approximately from 0-30 degrees, and the range of the incident angle is limited by the size of the crystal in the experiment, which means that the covered fundamental frequency spectrum range is very limited when the tunable frequency multiplication process is generated, and the application value of the output wavelength of the single-block periodic polarized lithium niobate crystal under the scheme of the quasi-phase matching is undoubtedly restricted.
Disclosure of Invention
In order to solve at least one of the technical problems existing in the prior art to a certain extent, the invention aims to provide a device for generating continuously tunable narrow-band laser in an extremely wide frequency spectrum.
The technical scheme adopted by the invention is as follows:
An apparatus for generating a continuously tunable narrowband laser over an extremely broad spectrum, comprising:
A narrow-band laser pump source module such as nanoseconds, picoseconds, even femtoseconds and the like can be tuned;
The controllable nonlinear frequency conversion module is formed by combining two semi-cylindrical prisms and a single nonlinear polarization crystal, and the nonlinear polarization crystal is arranged between the two semi-cylindrical prisms;
Based on changing the angle of pump light in the nonlinear polarization crystal as the leading, rotating the nonlinear polarization crystal according to the quasi-phase matching condition, and simultaneously, tightly attaching to the semi-cylindrical prism of the nonlinear polarization crystal to move back and forth so as to finish three processes of light incidence, nonlinear effect generation and light emergence; the pump light is incident to the first semi-cylindrical prism optical center from different angles in the air, the angle deflection is not changed in the process to realize the first process, the light is incident to the nonlinear polarized crystal from the optical center, the internal angle deflection occurs to generate nonlinear effect, and finally the light is emitted to the air from the crystal emergent port through the second semi-cylindrical prism optical center to receive and collect.
The scheme is further improved in that the pump light enters the nonlinear frequency conversion module in TE polarization mode at different angles, the vibration direction is parallel to the z axis of the crystal axis, light entering the nonlinear polarization crystal is extraordinary light, and phase mismatch of the pump light in the frequency multiplication process under different internal angles of the nonlinear polarization crystal is deduced.
The scheme is further improved in that the pump light obliquely enters the nonlinear polarization crystal to generate second harmonic, the phase matching in the x direction of the crystal is assumed, the phase mismatch in the y direction of the crystal is assumed, the nonlinear frequency conversion in the y direction is only considered, and the quasi-phase matching is realized by using the inverted lattice vector structure provided by the nonlinear crystal.
The scheme is further improved in that the numerical combination of the polarization period, the chirp degree, the duty ratio, the crystal specification and the like of the nonlinear polarization crystal is adjustable, so that the inverted lattice vector of the nonlinear polarization crystal is presented as a plurality of narrow-band inverted lattice vector fronts or ultra-narrow-band inverted lattice vector bands distributed at different positions, and the phase mismatch quantity in the multistage quasi-phase matching nonlinear frequency conversion process can be effectively compensated.
The scheme is further improved in that the polarization period of the nonlinear polarization crystal is 24 mu m, the chirp degree is 0, the light transmission length is 5mm, the width is 12mm, an inverted lattice vector structure along the light transmission direction is provided, and the phase mismatch quantity in the 1-10-order quasi-phase matching nonlinear frequency conversion process can be effectively compensated.
The scheme is further improved in that a plurality of narrow-band inverted lattice vector fronts or inverted lattice vector bands of the nonlinear polarization crystal participate in the nonlinear frequency conversion process under different internal angles, tunable fundamental frequency light with different wavelengths respectively corresponds to each inverted lattice vector, each inverted lattice vector can be effectively connected with the phase mismatch amount of the nonlinear frequency conversion process compensated by the previous inverted lattice vector under the specific internal angles of the crystal, the generation of extremely wide frequency spectrum tunable second harmonic is completed through a plurality of inverted lattice vectors of multi-order quasi-phase matching, tunable frequency multiplication is generated by 1-10-order quasi-phase matching, the coverage fundamental frequency light can reach 750nm-2700nm, tunable frequency multiplication covering longer waves is continuously generated by 1-order quasi-phase matching alone, the coverage fundamental frequency light can reach a wide spectrum range of 2700nm-4900nm, and therefore high-efficiency narrow-band frequency multiplication which is continuously tunable in a range of 325nm-2450nm is generated. It should be noted that, based on the specific design parameters of the nonlinear polarization crystal given above, the continuously tunable efficient narrowband frequency multiplication range that can be generated by using the multi-order quasi-phase matching mechanism and the angle tuning scheme is merely for better illustration and convenient understanding, and these equivalent modifications or substitutions are included in the scope of the claims of the present application.
The scheme is further improved in that the plane end of the first semi-cylindrical prism is closely attached to one side of the nonlinear polarized crystal where light enters, so that the light incidence process is completed, and the refractive index of the first semi-cylindrical prism is close to but still lower than that of the nonlinear polarized crystal; according to the Snell's law, the incidence angle of the semi-cylindrical prism is calculated from the internal angle of the nonlinear polarized crystal, the incidence of the pump light from the air is controlled to hang down to the cylindrical end of the semi-cylindrical prism, the direction of the pump light passes through the optical center of the semi-cylindrical prism, and the incidence angle is maintained in the propagation process.
The scheme is further improved in that the plane end of the second semi-cylindrical prism is closely attached to one light-emitting side of the nonlinear polarized crystal so as to complete the light-emitting process, and the refractive index of the second semi-cylindrical prism is close to but still higher than that of the nonlinear polarized crystal; the operating light enters from the nonlinear polarized crystal outlet port through the optical center of the plane end of the second semi-cylindrical prism, and the light deflects at the second semi-cylindrical prism according to the Snell's law, and keeps the refraction angle to be vertically emitted and received through the cylindrical end for collection.
The scheme is further improved in that the materials, the radiuses and the thicknesses of the two semi-cylindrical prisms can be changed, and the semi-cylindrical prisms can be moved to be better combined with nonlinear polarized crystals to form a steerable nonlinear frequency conversion module.
The scheme is further improved in that the tunable narrow-band laser pumping source module comprises a laser, a half-wave plate and a plano-convex lens; the laser is used for generating laser, and the laser is incident to the nonlinear frequency conversion module after sequentially passing through the half-wave plate and the plano-convex lens.
The beneficial effects of the invention include:
(1) The device for generating the continuous tunable narrow-band laser in the ultra-wide frequency spectrum, disclosed by the invention, abandons the traditional method of directly focusing incident light from air into a sample by using a nonlinear optical frequency conversion module consisting of two semi-cylindrical prisms and a single nonlinear polarization crystal (PPLN), and effectively expands the nonlinear frequency conversion spectrum by using a novel combined frequency conversion module and a PPLN sample internal angle tuning scheme through a multi-order quasi-phase matching mechanism even if the external incident angle is ideally adjusted to 90 degrees and the internal angle deflection of lithium niobate is approximately 30 degrees by using the traditional angle tuning method.
(2) The narrow-band nonlinear polarization crystal designed by the invention has flexible and controllable structure, is easy to prepare, utilizes 1-10-order quasi-phase matching to generate a device for continuously tunable narrow-band laser in an extremely wide frequency spectrum, wherein 1-10-order quasi-phase matching generates high-efficiency frequency multiplication covering tunable fundamental frequency light from 750nm to 2700nm, and solely generates high-efficiency frequency multiplication covering tunable fundamental frequency light from 2700nm to 4900nm continuously by 1-order quasi-phase matching, thereby having high energy conversion efficiency and being suitable for narrow-band lasers with pumping sources of nanoseconds, picoseconds, even femtoseconds and the like.
(3) The device for generating the continuous tunable narrow-band laser in the ultra-wide frequency spectrum has the advantages of small device size, easiness in preparation and processing of the semi-cylindrical prism, simple light path, strong mobility and wide application.
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In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following description is made with reference to the accompanying drawings of the embodiments of the present invention or the related technical solutions in the prior art, and it should be understood that the drawings in the following description are only for convenience and clarity of describing some embodiments in the technical solutions of the present invention, and other drawings may be obtained according to these drawings without the need of inventive labor for those skilled in the art.
FIG. 1 is a schematic diagram of an experimental apparatus for generating a continuously tunable narrow-band laser in an extremely broad spectrum in this example;
FIG. 2 is a graph showing the Fourier coefficient spectrum of a periodically poled lithium niobate crystal and the phase mismatch of the second harmonic generation process at different internal angles in this embodiment, wherein the abscissa is the inverted vector value, the left ordinate is the effective nonlinear coefficient, and the right ordinate is the matched fundamental frequency wavelength;
fig. 3 is a schematic diagram illustrating the connection of the periodic polarized lithium niobate crystal with internal angle tuning and multi-order quasi-phase matching to achieve ultra-wide frequency spectrum efficient frequency multiplication in this example, wherein fig. 3 (a) is a schematic diagram of m=1 to m=5-order quasi-phase matching, and fig. 3 (b) is a schematic diagram of m=6 to m=10-order quasi-phase matching;
Fig. 4 is a schematic diagram of incidence and emergence of fundamental frequency light in the process of completing internal angle tuning by cooperation of a periodically polarized lithium niobate crystal and two semi-cylindrical prisms in this example, where fig. 4 (a) is a schematic diagram of first-order quasi-phase matching demonstration, and fig. 4 (b) is a schematic diagram of first-order second-order quasi-phase matching demonstration.
Reference numerals illustrate: a laser 1; a half-wave plate 2; a plano-convex lens 3; a rotary table 4; semi-cylindrical prisms 5 and 7; periodically poled lithium niobate crystals 6; a filter 8; a photoelectric probe 9; a power meter 10; a spectrometer 11; a computer 12.
Detailed Description
Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the invention. The step numbers in the following embodiments are set for convenience of illustration only, and the order between the steps is not limited in any way, and the execution order of the steps in the embodiments may be adaptively adjusted according to the understanding of those skilled in the art.
In the description of the present invention, it should be understood that references to orientation descriptions such as upper, lower, front, rear, left, right, etc. are based on the orientation or positional relationship shown in the drawings, are merely for convenience of description of the present invention and to simplify the description, and do not indicate or imply that the apparatus or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present invention.
In the description of the present invention, a number means one or more, a number means two or more, and greater than, less than, exceeding, etc. are understood to not include the present number, and above, below, within, etc. are understood to include the present number. The description of the first and second is for the purpose of distinguishing between technical features only and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.
In the description of the present invention, unless explicitly defined otherwise, terms such as arrangement, installation, connection, etc. should be construed broadly and the specific meaning of the terms in the present invention can be reasonably determined by a person skilled in the art in combination with the specific contents of the technical scheme.
Term interpretation:
An extremely broad spectrum: the optical spectrum covering the uv-visible-ir band, which only relates to the visible-ir band or uv-visible band, is also within the understanding of extremely broad spectrum, i.e. the tunable wavelength range is concerned beyond the generally understood tens of nanometers.
As shown in fig. 1, the present embodiment provides an apparatus for generating a continuously tunable narrow-band laser in an extremely wide frequency spectrum, including:
A narrow-band laser pump source module such as nanoseconds, picoseconds, even femtoseconds and the like can be tuned;
the controllable nonlinear frequency conversion module is composed of two semi-cylindrical prisms and a single nonlinear crystal.
The tunable narrow-band laser pumping source module comprises a laser 1, a half-wave plate 2 and a planoconvex lens 3, wherein the laser 1 generates laser, the half-wave plate 2 for adjusting the polarization state and the planoconvex lens 3 for converging light spots are used for making the focused light spots enter a nonlinear frequency conversion module which is formed by combining two semi-cylindrical prisms 5 and 7 and a single periodic polarized lithium niobate crystal 6 (namely nonlinear polarized crystal) doped with 5% MgO at different angles, and the process is realized by rotating a frequency conversion module device arranged on a rotating table. The internal angle beta of the pump light in the periodically polarized lithium niobate crystal 6 is changed from 0 degrees to 60.9 degrees, and the pump light is regulated to vertically enter the cylindrical surface of the first semi-cylindrical prism from the air at different angles according to the Snell's law, wherein the pump light is ensured to always pass through the optical center direction of the semi-cylindrical prism. Further, the pump light emitted by the plane optical center of the first semi-cylindrical prism can enter the periodically polarized lithium niobate crystal to generate a frequency multiplication nonlinear effect, light at the output port of the crystal is refracted again, and is transmitted along the plane optical center of the second semi-cylindrical prism and emitted to the air to be collected and measured, the filter 8 is used for filtering fundamental frequency light, the filtered light reaches the photoelectric probe 9, the photoelectric probe 9 is connected with the power meter 10, and the power meter 10 and the spectrometer 11 are used for recording and measuring output light spectrums.
In this embodiment, as shown in fig. 2, the fourier coefficient spectrum of the periodically poled lithium niobate crystal is plotted against the phase mismatch of the second harmonic generation process under different internal angles, where the abscissa is the inverted vector value, the left ordinate is the effective nonlinear coefficient, and the right ordinate is the matched fundamental wavelength. The designed periodically poled lithium niobate crystal provides 10 inverted lattice vector fronts corresponding to m=1 to m=10 order quasi-phase matching respectively. When the pump light is normally incident, namely beta=0°, the intersection of the phase mismatch curve and each inverted lattice vector front can be known, and at this time, different inverted lattice vector fronts can provide effective phase compensation for nonlinear frequency conversion processes with different fundamental frequency wavelengths, so as to generate second harmonics with different frequencies. The internal angle beta of the pump light incident light periodical polarization lithium niobate crystal is effectively utilized, and the same inverted lattice vector front provided by the crystal at different angles provides effective phase compensation for the nonlinear frequency conversion process of different fundamental frequency wavelengths by taking 0-80 degrees as an example. By utilizing the multi-order quasi-phase matching and internal angle tuning mechanism of the periodically polarized lithium niobate crystal, effective phase compensation can be provided for the continuous nonlinear frequency conversion process in the ultra-wide frequency spectrum, so that efficient frequency multiplication is generated. In addition, the periodic polarized lithium niobate or the narrowband chirped periodic polarized lithium niobate crystal can provide a larger fourier coefficient than the effective fourier spectrum of the wideband chirped periodic polarized lithium niobate crystal, which effectively improves the conversion efficiency of the output tunable laser wavelength.
In this embodiment, as shown in fig. 3, the internal angle tuning and multi-order quasi-phase matching of the periodically polarized lithium niobate crystal achieve ultra-wide frequency spectrum efficient continuous frequency multiplication, and as can be seen from fig. 3 (a), in the ultra-wide frequency spectrum efficient frequency multiplication generation, the first inverted lattice vector front covers the fundamental frequency wavelength from 1719nm to 4900nm in the angle range of 0-50 ° at β, wherein the degeneracy point of the phase mismatch curve is effectively utilized; the second inverted lattice vector front covers fundamental wavelengths from about 1278-1719nm at an angle β ranging from 0-60.9; the third inverted lattice vector front covers fundamental wavelengths from about 1112-1278nm at an angle β ranging from 0-48.85 °; the fourth inverted lattice vector front covers fundamental wavelengths from about 1014-1112nm at an angle β ranging from 0-42.5 °; the fifth inverted lattice vector front covers fundamental wavelengths from about 949-1014nm at an angle β ranging from 0-37.2; the sixth inverted lattice vector front covers fundamental wavelengths from about 897-949nm at an angle β ranging from 0-34.4; the seventh inverted lattice vector front covers fundamental wavelengths from about 857-897nm at an angle β ranging from 0-31.9; the eighth inverted lattice vector front covers fundamental wavelengths from about 799-857nm at an angle β ranging from 0-40.3; the ninth inverted lattice vector front covers fundamental wavelengths from about 777-799nm at an angle range of β from 0-28.4; the tenth inverted lattice vector front covers the fundamental wavelength from about 750-777nm at an angle β ranging from 0-26.3 °. Meanwhile, the design scheme of the nonlinear crystal inverted lattice vector is not unique, only the distribution of the inverted lattice vectors is enough narrow-band, the frequency multiplication process of the tunable pump laser source can be effectively compensated, and the multi-order quasi-phase of the crystal is matched with the tunable base frequency light which covers the ultra-wide frequency spectrum under the internal angle tuning scheme, so that the ultra-wide frequency spectrum high-efficiency frequency multiplication can be effectively generated.
In this embodiment, as shown in fig. 4, the periodically polarized lithium niobate crystal and the two semi-cylindrical prisms cooperate to accomplish the incidence and emergence of the fundamental frequency light in the internal angle tuning generation process. Fig. 4 (a) shows that, for example, m=1-order quasi-phase matching, when the internal angles β of the periodically poled lithium niobate crystals are 0 °,10 °,20 °,30 °,40 ° and 48.5 °, respectively, according to the refractive index of the material selected for the first semi-cylindrical prism, the angles of the pump light incident on the semi-cylindrical prism and the horizontal direction are 0 °,12.37 °,24.96 °,38.05 °,52.32 ° and 67.32 °, respectively, as calculated by the snell's law of refraction, wherein the pump light perpendicularly enters the cylindrical surface of the semi-cylindrical prism and the directions thereof are over the optical center of the semi-cylindrical prism. In order to avoid the phenomenon that the emergent light after the nonlinear effect of the periodically polarized lithium niobate crystal is directly totally reflected with an air interface, the emergent light is better guided and further measured. The second semi-cylindrical prism can be applied to the situation that the refraction angle is larger, a schematic diagram of up-and-down movement of the semi-cylindrical prism device is constructed by the angle beta of 30 degrees, 40 degrees and 48.5 degrees, so that light is ensured to be incident, transmitted and emitted to the air along the optical center direction of the second semi-cylindrical prism, and the subsequent filtering test is facilitated. Similarly, fig. 4 (b) is an example of m=2-order quasi-phase matching, and the internal angles β of the periodically polarized lithium niobate crystals are respectively 0 °,20 °,40 °,60 °,60.9 °, and the angles of the corresponding pump light incident on the first semi-cylindrical prism and the horizontal direction are respectively 0 °,22.67 °,46.41 °,77.47 °, and 80.04 °. When the internal angle is increased, the crystal can move up and down so that the interaction length of pump light entering the crystal from the optical center of the first semi-cylindrical prism in the y direction is kept to be maximum, the light does not strike the side face of the crystal, the semi-cylindrical prism device is constructed to be 40 degrees with beta being 60 degrees and 60.9 degrees, the light emitted from the crystal is received by moving up and down, and the light is ensured to enter, propagate and exit into the air along the optical center direction of the second semi-cylindrical prism. Finally, a nonlinear frequency conversion module based on the combination of two semi-cylindrical prisms and a single nonlinear crystal generates high-efficiency frequency multiplication of extremely wide frequency spectrum under the pumping of a tunable narrow-band laser.
In the foregoing description of the present specification, reference has been made to the terms "one embodiment/example", "another embodiment/example", "certain embodiments/examples", and the like, means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: many changes, modifications, substitutions and variations may be made to the embodiments without departing from the spirit and principles of the invention, the scope of which is defined by the claims and their equivalents.
While the preferred embodiment of the present application has been described in detail, the present application is not limited to the above embodiments, and various equivalent modifications and substitutions can be made by those skilled in the art without departing from the spirit of the present application, and these equivalent modifications and substitutions are intended to be included in the scope of the present application as defined in the appended claims.
Claims (10)
1. An apparatus for generating a continuously tunable narrow-band laser light over an extremely broad spectrum, comprising:
A tunable narrowband laser pump source module;
The controllable nonlinear frequency conversion module is formed by combining two semi-cylindrical prisms and a single nonlinear polarization crystal, and the nonlinear polarization crystal is arranged between the two semi-cylindrical prisms;
Based on changing the angle of pump light in the nonlinear polarization crystal as the leading, rotating the nonlinear polarization crystal according to the quasi-phase matching condition, and simultaneously, tightly attaching to the semi-cylindrical prism of the nonlinear polarization crystal to move back and forth so as to finish three processes of light incidence, nonlinear effect generation and light emergence; the pump light is incident to the first semi-cylindrical prism optical center from different angles in the air, the angle deflection is not changed in the process to realize the first process, the light is incident to the nonlinear polarized crystal from the optical center, the internal angle deflection occurs to generate nonlinear effect, and finally the light is emitted to the air from the crystal emergent port through the second semi-cylindrical prism optical center to receive and collect.
2. The apparatus for generating a continuously tunable narrow-band laser in an ultra wide spectrum according to claim 1, wherein the pump light is incident on the nonlinear frequency conversion module in TE polarization mode at different angles, the vibration direction is parallel to the z-axis of the crystal axis, the light entering the nonlinear polarized crystal is extraordinary light, and the phase mismatch of the pump light in the frequency multiplication process at different internal angles of the nonlinear polarized crystal is deduced.
3. The apparatus for generating a continuously tunable narrow-band laser in an extremely wide spectrum according to claim 1, wherein said pump light is obliquely incident to a nonlinear polarization crystal to generate a second harmonic, and the nonlinear frequency conversion is only considered in the y direction assuming that the phase of the crystal is matched in the x direction, and the quasi-phase matching is realized by using an inverted lattice vector structure provided by the nonlinear crystal.
4. The device for generating continuously tunable narrow-band laser light in an extremely wide spectrum according to claim 1, wherein the polarization period, chirp degree, duty cycle and crystal specification of the nonlinear polarization crystal are adjustable, and positive and negative domain structures of a series of polarization directions along the y direction are provided, so that the inverted lattice vector of the nonlinear polarization crystal is presented as a plurality of narrow-band inverted lattice vectors or extremely narrow-band inverted lattice vectors distributed at different positions, and the phase mismatch amount in the multi-order quasi-phase matching nonlinear frequency conversion process can be effectively compensated.
5. The device for generating a continuously tunable narrow-band laser in an extremely wide spectrum according to claim 4, wherein the nonlinear polarization crystal has a polarization period of 24 μm, a chirp degree of 0, a light transmission length of 5mm and a width of 12mm, and an inverted lattice vector structure along the light transmission direction is provided, which can effectively compensate for the phase mismatch in the 1-10 order quasi-phase matching nonlinear frequency conversion process.
6. The device for generating continuously tunable narrow-band laser in an extremely wide frequency spectrum according to claim 5, wherein a plurality of narrow-band inverted lattice fronts or inverted lattice bands of the nonlinear polarization crystal participate in the nonlinear frequency conversion process under different internal angles respectively corresponding to tunable fundamental frequency light with different wavelengths, each inverted lattice vector can be effectively connected with the phase mismatch amount of the nonlinear frequency conversion process of the previous inverted lattice vector compensation under the specific internal angles of the crystal, the generation of extremely wide frequency spectrum tunable second harmonic is completed through the plurality of inverted lattice vectors of the multi-order quasi-phase matching, tunable frequency multiplication is generated by the 1-10-order quasi-phase matching, tunable frequency multiplication covering the fundamental frequency light can reach 750nm-2700nm, tunable frequency multiplication covering longer waves is continuously generated by the 1-order quasi-phase matching alone, and wide spectrum range covering the fundamental frequency light can reach 2700nm-4900nm, thereby generating continuously tunable high-efficiency narrow-band frequency multiplication in the range 325nm-2450 nm.
7. The apparatus for generating a continuously tunable narrow-band laser light in an extremely wide spectrum according to claim 1, wherein the planar end of said first semi-cylindrical prism is closely attached to the light-entering side of the nonlinear polarized crystal to complete the light incidence process, and the refractive index of said first semi-cylindrical prism is close to but still lower than that of the nonlinear polarized crystal; according to the Snell's law, the incidence angle of the semi-cylindrical prism is calculated from the internal angle of the nonlinear polarized crystal, the incidence of the pump light from the air is controlled to hang down to the cylindrical end of the semi-cylindrical prism, the direction of the pump light passes through the optical center of the semi-cylindrical prism, and the incidence angle is maintained in the propagation process.
8. The device for generating a continuously tunable narrow-band laser light in an extremely wide spectrum according to claim 1, wherein the planar end of said second semi-cylindrical prism is closely attached to the light-emitting side of the nonlinear polarized crystal to complete the light-emitting process, and the refractive index of the second semi-cylindrical prism is close to but still higher than that of the nonlinear polarized crystal; the operating light enters from the nonlinear polarized crystal outlet port through the optical center of the plane end of the second semi-cylindrical prism, and the light deflects at the second semi-cylindrical prism according to the Snell's law, and keeps the refraction angle to be vertically emitted and received through the cylindrical end for collection.
9. The apparatus of claim 1, wherein the material, radius, and thickness of two of said semi-cylindrical prisms are variable, said semi-cylindrical prisms being movable to better combine with non-linearly polarized crystals to form a steerable non-linear frequency conversion module.
10. The apparatus for generating a continuously tunable narrowband laser over an extremely wide spectrum according to claim 1, wherein the tunable narrowband laser pump source module comprises a laser, a half-wave plate, and a plano-convex lens; the laser is used for generating laser, and the laser is incident to the nonlinear frequency conversion module after sequentially passing through the half-wave plate and the plano-convex lens.
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6282014B1 (en) * | 1999-06-09 | 2001-08-28 | Northrop Grumman Corporation | Cascade optical parametric oscillator for down-conversion |
| US20040192040A1 (en) * | 2003-03-27 | 2004-09-30 | National Taiwan University | Method of fabricating two-dimensional ferroelectric nonlinear crystals with periodically inverted domains |
| CN105190422A (en) * | 2013-03-14 | 2015-12-23 | 雷蒙特亚特特拉维夫大学有限公司 | Tunable nonlinear beam shaping by a non-collinear interaction |
| CN106848809A (en) * | 2017-03-06 | 2017-06-13 | 李志远 | A kind of generation is visible to infrared band pole broadband, the device of super continuous laser |
| CN107732642A (en) * | 2017-10-01 | 2018-02-23 | 李志远 | Produce the device and non-linear laser crystal preparation method of the visible super continuous laser near infrared band wideband adjustable |
| CN115064927A (en) * | 2022-06-09 | 2022-09-16 | 广东晶启激光科技有限公司 | Nonlinear frequency conversion device for laser |
| CN115632300A (en) * | 2022-10-13 | 2023-01-20 | 华南理工大学 | Method for generating tunable narrow-band laser |
| CN116348814A (en) * | 2020-10-11 | 2023-06-27 | 维林光电公司 | Ultraviolet laser system, apparatus and method |
-
2024
- 2024-01-18 CN CN202410073969.5A patent/CN117996556A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6282014B1 (en) * | 1999-06-09 | 2001-08-28 | Northrop Grumman Corporation | Cascade optical parametric oscillator for down-conversion |
| US20040192040A1 (en) * | 2003-03-27 | 2004-09-30 | National Taiwan University | Method of fabricating two-dimensional ferroelectric nonlinear crystals with periodically inverted domains |
| CN105190422A (en) * | 2013-03-14 | 2015-12-23 | 雷蒙特亚特特拉维夫大学有限公司 | Tunable nonlinear beam shaping by a non-collinear interaction |
| CN106848809A (en) * | 2017-03-06 | 2017-06-13 | 李志远 | A kind of generation is visible to infrared band pole broadband, the device of super continuous laser |
| CN107732642A (en) * | 2017-10-01 | 2018-02-23 | 李志远 | Produce the device and non-linear laser crystal preparation method of the visible super continuous laser near infrared band wideband adjustable |
| CN116348814A (en) * | 2020-10-11 | 2023-06-27 | 维林光电公司 | Ultraviolet laser system, apparatus and method |
| CN115064927A (en) * | 2022-06-09 | 2022-09-16 | 广东晶启激光科技有限公司 | Nonlinear frequency conversion device for laser |
| CN115632300A (en) * | 2022-10-13 | 2023-01-20 | 华南理工大学 | Method for generating tunable narrow-band laser |
Non-Patent Citations (2)
| Title |
|---|
| 李雪;延凤平;谭思宇;: "基于PPLN晶体的可调谐太赫兹波辐射特性研究", 光电子.激光, no. 12, 15 December 2013 (2013-12-15) * |
| 马博琴;马冬莉;李志远;张道中;: "准周期铁电晶体中不同阶次的准相位匹配谐频", 光学学报, no. 12, 15 December 2009 (2009-12-15) * |
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