CN113872023B - Device for continuously adjusting laser pulse time width - Google Patents
Device for continuously adjusting laser pulse time width Download PDFInfo
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- CN113872023B CN113872023B CN202111037575.7A CN202111037575A CN113872023B CN 113872023 B CN113872023 B CN 113872023B CN 202111037575 A CN202111037575 A CN 202111037575A CN 113872023 B CN113872023 B CN 113872023B
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- 230000010287 polarization Effects 0.000 claims abstract description 33
- 230000008859 change Effects 0.000 claims description 5
- 230000005540 biological transmission Effects 0.000 claims description 2
- 230000003287 optical effect Effects 0.000 abstract description 7
- 239000000523 sample Substances 0.000 description 16
- 238000000034 method Methods 0.000 description 8
- 230000001105 regulatory effect Effects 0.000 description 4
- 230000008569 process Effects 0.000 description 3
- 230000002123 temporal effect Effects 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 230000001808 coupling effect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 230000008707 rearrangement Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000001052 transient effect Effects 0.000 description 1
Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/005—Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/005—Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping
- H01S3/0057—Temporal shaping, e.g. pulse compression, frequency chirping
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/005—Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping
- H01S3/0071—Beam steering, e.g. whereby a mirror outside the cavity is present to change the beam direction
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- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- Optics & Photonics (AREA)
- Lasers (AREA)
Abstract
The invention discloses a device for continuously adjusting the time width of laser pulse, comprising: beam splitters, polarizing beam splitters, delay lines, half wave plates, and stimulated Mie scattering samples. One beam of pulse laser is divided into two beams of light, wherein one beam of pulse light sequentially passes through a delay line, a polarization spectroscope and a convex lens and then enters a stimulated Mie scattering sample to generate a stimulated scattering condition, the other beam of light sequentially passes through a half-wave plate, a spectroscope and a polarization spectroscope and then is transmitted in a collinear way with the former beam of light, the stimulated Mie scattering condition generated by the former beam of light scatters to generate a backward transmitted phase conjugated light, and the relative optical path difference of the two beams of light is adjusted through the delay line, so that the required pulse width of the stimulated scattering light is obtained. The backward stimulated scattered light can be separated and extracted when passing through the beam splitter.
Description
Technical Field
The invention relates to the technical field of laser pulse parameter regulation and control, in particular to a device for continuously regulating the laser pulse time width.
Background
At present, since the first laser is made, laser light has been widely used in many fields of science, technology, economy, military and social development due to its excellent characteristics, far beyond the original expectation of people. In laser applications, the temporal width of the laser pulses is very important, and many applications require laser pulses with different temporal widths and continuous adjustment over a relatively large range. In the prior art, there are several methods for obtaining different pulse time widths, for example, by changing the length of the resonant cavity of the Q-switched laser, and changing the time required for cavity emptying, to change the laser pulse width; a fast optical switch is used to obtain the required pulse width; compressing the pulses using a mode locking technique; the fixed pulses are piled up in the time dimension by a complex structure, and the required pulse time width is obtained by widening the short pulses.
In the above device method, the pulse width cannot be adjusted in real time or can be adjusted, but the adjustment range is limited, if the pulse width is overlapped to change the pulse width, the pulse may become comb-shaped, and the coherence between the overlapped pulses is lost.
Disclosure of Invention
The invention aims to provide a device for continuously adjusting the time width of laser pulse, which can continuously adjust the output laser pulse width in a large range without changing the beam mode and the pulse shape, forms the laser pulse with the required time width and is suitable for outputting any laser wavelength.
The invention adopts the technical scheme that:
a device for continuously adjusting the time width of laser pulse comprises a first beam splitter 1, a delay light path and an stimulated scattering light path;
the delay light path comprises a first reflecting mirror, a first right-angle prism, a second right-angle prism and a second reflecting mirror,
the stimulated scattering light path comprises a polarization beam splitter prism, a half wave plate, a second beam splitter lens, a convex lens and a sample, wherein a reflected light path of the first beam splitter lens passes through the first reflector, the first right angle prism, the second right angle prism and the second reflector and then reaches a light inlet of the polarization beam splitter prism, a transmitted light beam of the first beam splitter lens passes through the half wave plate and the second beam splitter lens and then enters a straight-through incidence surface of the polarization beam splitter prism to coincide with the reflected light, the two light beams interact with the sample after passing through the convex lens and generate a back stimulated scattering light beam, and the stimulated scattering light beam returns along an original path after passing through the polarization beam splitter prism and then passes through the second beam splitter lens 9 to output a required light beam.
The sample is an excited Mie scattering sample.
The half-wave plates are multiple, and the corresponding wavelength of each half-wave plate is different.
The half wave plate can be replaced by a Faraday rotation device.
The invention divides the light path into two paths through the first beam splitter, one path is transmitted through the delay light path and then is combined with the transmission light path and then enters the stimulated scattering light path, one beam of light is utilized to generate stimulated Mie scattering condition to carry out conjugate reflection on the other beam of light, thus forming laser pulse with required time width.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic structural view of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without any inventive effort, are intended to be within the scope of the invention.
As shown in fig. 1, the invention comprises a first beam splitter 1, a delay light path and an stimulated scattering light path; the polarized light is separated through a first beam splitter 1, one beam of light is overlapped with the polarized light of the other beam of light passing through the stimulated scattering light path after passing through a delay light path to obtain a light path with required delay, and then the light path is interacted with the polarized light, wherein the delay light path comprises a first reflector 2, a first right angle prism 3, a second right angle prism 4 and a second reflector 5; the stimulated scattering light path comprises a polarization beam splitter prism 6, a half-wave plate 7, a second beam splitter 9, a convex lens 10 and a sample 11, wherein a reflected light beam of the first beam splitter 1 passes through the first reflector 2, the first right-angle prism 3, the second right-angle prism 4 and the second reflector 5 and then reaches a vertical incidence surface of the polarization beam splitter prism 6, a transmitted light beam of the first beam splitter 1 enters the direct incidence surface of the polarization beam splitter prism 6 through the half-wave plate 7 and the second beam splitter 9 and coincides with another light beam, the two light beams interact with the light path of the sample 11 through the convex lens 10 and generate a back stimulated scattering light beam, and the back stimulated scattering light beam returns along the original path after passing through the polarization beam splitter prism 6 and outputs a required light beam through the second beam splitter 9.
The invention has the following actual working process: the incident light is divided into two linearly polarized light beams by the first beam splitter 1, the first light beam sequentially passes through the first reflector 2, the two right-angle triple prisms, the first right-angle triple prism 3, the second right-angle triple prism 4, the second reflector 5 and the polarization beam splitter 6 and then coincides with the second light beam, wherein the two right-angle triple prisms are used as delay lines together to change the optical path length of the first light beam and adjust the relative time of the first light beam and the second light beam. The second light beam leaves the first spectroscope 1, passes through the half-wave plate 7, the polarization state is rotated by 90 degrees to become parallel polarized light, and then passes through the second beam splitter 9, reaches the polarization beam splitter prism 6 to coincide with the path of the first light beam, and finally is focused on the sample 11 through the convex lens 10. The sample is an excited Mie scattering sample. The stimulated scattering sample generates a backward stimulated scattering condition, namely a dynamic Bragg grating, under the action of an incident pumping beam, and generates backward stimulated scattering conjugated light for the other beam of light; the polarization spectroscope 6 synthesizes two light beams with mutually perpendicular polarization directions into one light beam, and the light beam is incident into a Mie scattering sample and separates two light beams with different opposite polarization directions; the delay line is used for adjusting the relative time of the two beams of light; the half wave plate rotates the polarization direction of the light beam by 90 degrees.
According to the device, one beam of light generates stimulated Mie scattering conditions, the other beam of light vertically polarized generates back stimulated scattering, and then the relative time of the two beams of light is regulated by regulating the delay line, so that the time length of the mutual coupling action of the two beams of light is regulated, and the pulse time width with any length is obtained. The two light beams with perpendicular polarization directions are combined into one light beam by using a polarization spectroscope, and the stimulated scattered light with perpendicular polarization directions which are transmitted reversely is split and extracted.
In particular operation, the second beam reaches the sample at a time equal to or earlier than the time of arrival of the first beam. When the first beam arrives, the sample is excited, the condition of backward stimulated Mie scattering is generated, and meanwhile, the second beam is scattered, and the scattered light of the second beam also generates backward scattered light. The polarization direction of the two backward stimulated scattered lights is not changed, so that only the backward stimulated scattered light of the second beam can reach the beam splitter 9 through the polarization beam splitter and turn, and the original light path is separated. Thus, the optical path length of the first light beam can be adjusted by adjusting the delay line, so that stimulated scattered light with different pulse time widths can be obtained.
Where the laser wavelength is insensitive, the applicable range includes visible light and infrared light by replacing the half-wave plate with the desired wavelength or by replacing the half-wave plate with a faraday rotation arrangement. The device can adapt to the point requirements of a plurality of wavelengths by replacing the corresponding half wave plate, and can adapt to the surface requirements of a plurality of wavelengths by the Faraday rotation device.
The invention does not change the beam mode and the pulse shape, the output laser pulse width can be continuously adjusted in a large range, and the invention is suitable for outputting any laser wavelength. The data are further described in the following specific examples:
example one: the nanosecond laser output by Nd-YAG is used as incident laser to the device, the wavelength of the input laser is 106nm, the laser pulse width is 25 ns, the single pulse energy is 5mJ, the spot diameter is 7mm, and the element 10 is a convex lens with the focal length of 100 mm. The incident laser is divided into two beams of light with the same polarization direction after passing through the first beam splitter 1, one beam of light passes through the half-wave plate 7, the polarization direction is rotated by 90 degrees, and then the light passes through the second beam splitter 9, and the light is incident into the polarization beam splitter 6 as p-polarized light, and can pass along a straight line. The other beam reflected by the first beam splitter 1 is incident into an extension line through a reflecting mirror to obtain certain delay, and then is incident into the polarization beam splitter prism 6 through the second reflecting mirror 5 as s-polarized light, the direction of the s-polarized light is changed by 90 degrees, so that the s-polarized light is overlapped with the p-polarized light of the other beam, and the two beams of light overlapped on the path are incident into the stimulated Mie scattering sample 11 through the convex lens 10.
The s polarized light beam passing through the delay line acts on the sample 11 to form a condition of stimulated Mie scattering, namely a transient bragg grating is formed, and the condition of stimulated Mie scattering also generates Mie scattering on the other beam of p polarized light, namely backward transmitted phase conjugated light, the polarization state of the backward transmitted phase conjugated light is unchanged, namely the polarization state of the backward transmitted phase conjugated light is the same as that of the incident phase, and the p polarized light passes through the polarization splitting prism 6 along a straight line and then passes through the second beam splitting mirror 9, so that the light beam with the required pulse width is separated from the original light path. The pulse width was 20ns as measured by a fast photo probe.
In the second example, the laser parameters and the elements used were larger than those in the first example, the optical path length of the delay line was increased, the distance of the prism 4 from the prism 3 was 45cm, and the pulse width outputted from the beam splitter 9 was 17ns.
In example three, the laser parameters and the elements used were compared with example one, the optical path length of the delay line was increased to 2.2m, and the pulse width output from the beam splitter 9 was 7ns.
In example three, the laser parameters and the elements used were compared with example one, the optical path length of the delay line was increased to 3.0m, and the pulse width output from the beam splitter 9 was 2ns.
In the description of the present invention, it should be noted that, for the azimuth words such as "center", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., the azimuth and positional relationships are based on the azimuth or positional relationships shown in the drawings, it is merely for convenience of describing the present invention and simplifying the description, and it is not to be construed as limiting the specific scope of protection of the present invention that the device or element referred to must have a specific azimuth configuration and operation.
It should be noted that the terms "first," "second," and the like in the description and in the claims of the present application are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate in order to describe the embodiments of the present application described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
Note that the above is only a preferred embodiment of the present invention and uses technical principles. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, while the present invention has been described in connection with the above embodiments, it is to be understood that the invention is not limited to the specific embodiments disclosed and that many other and equally effective embodiments may be devised without departing from the spirit of the invention, and the scope thereof is determined by the scope of the appended claims.
Claims (3)
1. An apparatus for continuously adjusting the time width of a laser pulse, characterized by: the device comprises a first beam splitter (1), a delay light path and an stimulated scattering light path;
the delay light path comprises a first reflecting mirror, a first right-angle prism, a second right-angle prism and a second reflecting mirror;
the stimulated scattering light path comprises a polarization beam splitter prism, a half wave plate, a second beam splitter lens, a convex lens and a sample, wherein a reflected light path of the first beam splitter lens passes through the first reflector, the first right angle prism, the second right angle prism and the second reflector and then reaches a light inlet of the polarization beam splitter prism, a transmitted light beam of the first beam splitter lens passes through the half wave plate and the second beam splitter lens and then enters a straight-through incident surface of the polarization beam splitter prism to coincide with the reflected light, the two light beams interact with the sample after passing through the convex lens and generate a back stimulated scattering light beam, and the stimulated scattering light beam returns along an original path after passing through the polarization beam splitter prism and then passes through the second beam splitter lens to output a required light beam; the light path is divided into two paths through the first beam splitter, one path is transmitted through the delay light path and then is combined with the transmission light path and then enters the stimulated scattering light path, one beam of light is utilized to generate stimulated Mie scattering conditions to perform conjugate reflection on the other beam of light, so that laser pulses with required time width are formed, the whole device can not change the beam mode and the pulse shape, the output laser pulse width can be continuously adjusted in a large range, the laser pulses with the required time width are formed, and the device is suitable for outputting any laser wavelength; the sample is an excited Mie scattering sample.
2. The apparatus for continuously adjusting the time width of a laser pulse according to claim 1, wherein said half-wave plates have a plurality of types, and the corresponding wavelength of each half-wave plate is different.
3. The apparatus for continuously adjusting the time width of a laser pulse according to claim 2, wherein: the half-wave plate is replaced by a Faraday rotation device.
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| CN114924422B (en) * | 2022-04-03 | 2023-09-29 | 上海图灵智算量子科技有限公司 | Ultrafast laser pulse sequence modulator and modulation method |
| CN115016133B (en) * | 2022-06-02 | 2023-03-14 | 北京理工大学 | Novel carrier modulation pulse generation device and method |
| CN116735387B (en) * | 2023-08-08 | 2023-11-14 | 河海大学 | Device and method for testing impulse power response of grotto under complex conditions |
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2021
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