CN114295227B - System and method for measuring orbital angular momentum beam topology charge value - Google Patents
System and method for measuring orbital angular momentum beam topology charge value Download PDFInfo
- Publication number
- CN114295227B CN114295227B CN202111620485.0A CN202111620485A CN114295227B CN 114295227 B CN114295227 B CN 114295227B CN 202111620485 A CN202111620485 A CN 202111620485A CN 114295227 B CN114295227 B CN 114295227B
- Authority
- CN
- China
- Prior art keywords
- angular momentum
- orbital angular
- lens
- light
- interference
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 15
- 230000008878 coupling Effects 0.000 claims abstract description 23
- 238000010168 coupling process Methods 0.000 claims abstract description 23
- 238000005859 coupling reaction Methods 0.000 claims abstract description 23
- 238000005259 measurement Methods 0.000 claims abstract description 10
- 230000001427 coherent effect Effects 0.000 claims abstract description 5
- 239000004973 liquid crystal related substance Substances 0.000 claims description 18
- 230000003287 optical effect Effects 0.000 claims description 15
- 238000005086 pumping Methods 0.000 claims description 10
- 238000004891 communication Methods 0.000 description 5
- 230000010287 polarization Effects 0.000 description 4
- 238000001514 detection method Methods 0.000 description 3
- 238000011160 research Methods 0.000 description 3
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
Images
Landscapes
- Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)
- Instruments For Measurement Of Length By Optical Means (AREA)
Abstract
The invention provides a system and a method for measuring topological charge values of orbital angular momentum beams. The orbital angular momentum beam generating unit obtains an orbital angular momentum beam carrying topological charges; the orbital angular momentum beam coupling unit converts the orbital angular momentum beam into a coherent state; the orbital angular momentum beam interference unit performs equal-thickness interference on the orbital angular momentum beam on the basis of the orbital angular momentum beam interference unit to obtain a required orbital angular momentum beam interference form for measurement. The invention realizes the measurement of the number and positive and negative values of orbital angular momentum topological charges, can measure high-order topological charge values, reduces the cost of a measuring system and greatly improves the efficiency of the orbital angular momentum beam in practical application.
Description
Technical Field
The invention relates to the technical field of quantum information and optical communication, in particular to a system and a method for measuring an orbital angular momentum beam topology charge value.
Background
Photons have multiple degrees of freedom, such as polarization, spin angular momentum, and orbital angular momentum. The spin angular momentum is related to the circular polarization state of the photon, and its eigenstate can be calculated by the spin angular momentum operator left-hand circular polarization state |L>
And right-hand circular polarization state |R>/>
To show that a common two-dimensional hilbert space can be constructed by using spin angular momentum. In 1992, orbital angular momentum was formally known, and it was proved by research that single photons contain definite orbital angular momentum
Is also called as characteristic quantum number of orbital angular momentumFor topology charge number +.>
The value of (2) may be any integer. Theoretically +.>
The value is infinite, namely, the coding in the infinite wikipedit space in the quantum information and optical communication technology can be realized by using orbital angular momentum. The photons are used as information carriers, so that the Hilbert space coding with high dimension can modulate the orbital angular momentum of the photons, and the information quantity carried by the photons is greatly improved. In schemes that utilize orbital angular momentum for optical and quantum communications, measuring the photon orbital angular momentum for encoding is a key one and last step in orbital angular momentum communications. With the increasing heat of the research of orbital angular momentum, how to measure the orbital angular momentum of photons more conveniently and effectively becomes one of the hot spot fields of research nowadays.
The prior art discloses a patent of a detection system for identifying the topology charge number of an OAM beam based on signal crosstalk distribution characteristics, wherein an OAM multiplexing module performs orbital angular momentum multiplexing on vortex beams; the first optical antenna module emits a vortex beam signal into an optical communication channel; the second optical antenna receives the light beam, the OAM demultiplexing module decomposes the received light signal to a group of OAM modes and converts the OAM signals into crosstalk distribution electric signals, the OAM light beam topology charge number detection module analyzes input data to obtain the topology charge number of the vortex light beam, the characteristics of crosstalk distribution are utilized, topology charge number information contained in the crosstalk distribution is fully utilized, so that the accuracy rate of the vortex light beam topology charge number detection is high, the speed is high, and high-speed information transmission is realized. However, the patent has been recently reported for measuring magnitude and sign of orbital angular momentum beam topology charge.
In the existing application, the orbital angular momentum carried by photons has a larger topological charge value, and meanwhile, the negative topological charge is also widely used. Thus topological charge value of orbital angular momentum
In measurement, not only the absolute value of the numerical value of the measurement device is required to be measured, but also the sign of the topological load value is required to be measured, the simultaneous measurement of two variables is a challenge, and the light weight of the measurement device is also a problem to be overcome in practical application.
Disclosure of Invention
The invention provides a system for measuring the topological charge value of an orbital angular momentum beam, which can measure the magnitude and sign of the topological charge value of the orbital angular momentum beam.
It is yet another object of the present invention to provide a method of measuring orbital angular momentum beam topology charge.
In order to achieve the technical effects, the technical scheme of the invention is as follows:
a system for measuring topological charge value of orbital angular momentum beam comprises a pumping light source, an orbital angular momentum beam generating unit, an orbital angular momentum beam coupling unit, an orbital angular momentum beam interference unit and a light detector which are connected in sequence;
the pump light source generates a continuous Gaussian beam; the orbital angular momentum beam generating unit generates an orbital angular momentum beam carrying a required topological charge; the orbital angular momentum beam coupling unit is used for splitting the orbital angular momentum beam and then coupling the beam to obtain a coherent orbital angular momentum beam; the orbital angular momentum beam interference unit performs secondary interference on the orbital angular momentum beam to obtain a required interference pattern; the light detector observes the interference pattern to obtain the magnitude and the positive and negative of the orbital angular momentum topological charge value.
Further, the orbital angular momentum beam generating unit comprises a first lens, a second lens, a polaroid, a liquid crystal Spatial Light Modulator (SLM) and a computer (PC) which are sequentially connected; the pumping light source is connected with the first lens, the first lens and the second lens form a lens group, and the input pumping light is subjected to beam expansion and collimation; the polarizing plate converts the Gaussian beam into linearly polarized light; the computer PC delivers a calculation hologram to the liquid crystal spatial light modulator SLM, converting linearly polarized light into a desired orbital angular momentum beam.
Further, the orbital angular momentum beam coupling unit comprises a first beam splitter, a first total reflection mirror and a Faraday reflection mirror; the first beam splitter splits the passing orbital angular momentum beam into a first beam and a second beam; the first light beam is reflected at the first total reflection mirror, and the second light beam is rotated 180 DEG at the Faraday reflection mirror and reflected; the first light beam and the second light beam re-enter the first beam splitter to be coupled into one beam of light and then exit.
Further, the first total reflection mirror is equal to the distance between the Faraday reflection mirror and the first beam splitter; the first total reflection mirror and the Faraday reflection mirror are both total reflection mirrors plated with high reflection films; the beam splitting ratio of the first beam splitter is 50:50.
Further, the orbital angular momentum beam interference unit comprises a third lens, a second beam splitter, a plano-convex lens, a second total reflection mirror and a fourth lens; the third lens converges the parallel light and then turns the parallel light into a divergent light beam; the plano-convex lens and the second total reflecting mirror interfere the scattered orbital angular momentum beam to obtain a required orbital angular momentum interference beam; the second beam splitter receives the light beam and reflects the light beam to enter the fourth lens; the fourth lens reconverges the divergent light into parallel light to obtain a desired interference pattern and is used for measuring the topological charge value.
Further, the beam splitting ratio of the second beam splitter is 50:50; the second total reflecting mirror is a total reflecting mirror plated with a high-reflection film; the third lens and the fourth lens are converging lenses; the position of the plano-convex lens is behind the focal point f of the third lens; the plano-convex lens is closely connected with the second total reflection mirror.
A method of measuring orbital angular momentum beam topology charge, comprising the steps of:
s1: generating a continuous Gaussian beam by using a pumping light source, wherein the Gaussian beam enters an orbital angular momentum beam generating unit;
s2: the Gaussian beam entering the orbital angular momentum beam generating unit is respectively composed of a first lens and a second lensAfter passing through the lens group, the Gaussian beam is expanded and collimated, and then the Gaussian beam is converted into linearly polarized light through a polarizing plate; under the modulation of a computer PC, linearly polarized light enters a liquid crystal spatial light modulator SLM and is converted into light with the following characteristics
Orbital angular momentum beams of the individual topological charges; the orbital angular momentum beam enters the orbital angular momentum beam coupling unit;
s3: the orbital angular momentum beam entering the orbital angular momentum beam coupling unit is divided into a first beam and a second beam at a first beam splitter, and the first beam and the second beam are coupled into a beam at the first beam splitter again to exit through the reflection of a first total reflection mirror and the rotation and reflection of a Faraday reflection mirror, and enter the orbital angular momentum beam interference unit;
s4: the orbital angular momentum beam entering the orbital angular momentum beam interference unit is changed into divergent light from parallel light at the third lens, then is transmitted into the plano-convex lens at the second beam splitter, the light refracted by the plano-convex lens is reflected by the second total reflection mirror at the bottom of the plano-convex lens and then reenters the plano-convex lens to generate interference phenomenon, then the interfered orbital angular momentum beam returns to the second beam splitter, is reflected at the second beam splitter and enters the fourth lens to be changed into parallel light again, and leaves the orbital angular momentum beam interference unit;
s5: the orbital angular momentum beam leaving the orbital angular momentum beam interference unit enters the optical detector to obtain an interference pattern of the orbital angular momentum beam modulated by the system, so that the magnitude and the positive and negative of the topological charge value of the orbital angular momentum beam are respectively judged through the number of the interference maximum bright spots of the interference pattern and the rotation direction of the interference fringes.
Further, in the step S2, the computer PC projects a calculation hologram onto the liquid crystal spatial light modulator SLM, and generates a desired orbital angular momentum beam by changing the liquid crystal array.
Further, in the step S4, the plano-convex lens generates a desired interference phenomenon by a refraction phenomenon caused by different refractive indexes of different media and an optical path difference caused by a height difference between the cambered surface of the plano-convex lens and the total reflection mirror.
Further, the relation between the number n of the interference maximum bright spots and the topological charge value l is n= 2|l |, and the relation between the rotating direction of the interference fringes and the positive and negative values of the topological charge value is that clockwise rotation is positive and anticlockwise rotation is negative.
Compared with the prior art, the technical scheme of the invention has the beneficial effects that:
(1) The invention realizes the generation of the orbital angular momentum beam which can be stably coupled by using the separation characteristic and the convergence characteristic of the beam splitter, so that the interference of the orbital angular momentum beam can be stably carried out; (2) The plane convex lens is used for realizing equal-thickness interference of orbital angular momentum beams, and the generated interference patterns are visual and clear, so that the resolution is facilitated; (3) The topology charge value of orbital angular momentum is measured by adopting an optical interference method, and under the advantage of keeping the high topology charge value measurable by the interference measurement, the positive and negative values of the topology charge value can be measured.
Drawings
FIG. 1 is a block diagram of a system of the present invention;
FIG. 2 is a flow chart of the method of the present invention;
FIG. 3 is a graph showing the results of an embodiment of the present invention.
Detailed Description
The drawings are for illustrative purposes only and are not to be construed as limiting the present patent;
for the purpose of better illustrating the embodiments, certain elements of the drawings may be omitted, enlarged or reduced and do not represent the actual product dimensions;
it will be appreciated by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.
The technical scheme of the invention is further described below with reference to the accompanying drawings and examples.
Example 1
As shown in fig. 1, a system for measuring topological charge values of an orbital angular momentum beam comprises a pumping light source 10, an orbital angular momentum beam generating unit 11, an orbital angular momentum beam coupling unit 12, an orbital angular momentum beam interference unit 13 and a light detector 14 which are connected in sequence;
the pump light source 10 generates a continuous gaussian beam; the orbital angular momentum beam generating unit 11 generates an orbital angular momentum beam carrying a desired topological charge; the orbital angular momentum beam coupling unit 12 is configured to split the orbital angular momentum beam and then couple the beam to obtain a coherent orbital angular momentum beam; the orbital angular momentum beam interference unit 13 performs secondary interference on the orbital angular momentum beam to obtain a required interference pattern; the light detector 14 observes the interference pattern to obtain magnitude and sign of the orbital angular momentum topology charge.
The orbital angular momentum beam generating unit 11 includes a first lens 110, a second lens 111, a polarizing plate 112, a liquid crystal spatial light modulator SLM113, and a computer PC114 connected in this order; the pump light source 10 is connected with a first lens 110, and the first lens 111 and a second lens 112 form a lens group to expand and collimate the input pump light; the polarizing plate 112 converts the gaussian beam into linearly polarized light; the computer PC114 delivers a computed hologram to the liquid crystal spatial light modulator SLM113, converting linearly polarized light into a desired orbital angular momentum beam.
The orbital angular momentum beam coupling unit 12 comprises a first beam splitter 120, a first total reflection mirror 121 and a faraday mirror 122; the first beam splitter 120 splits the passing orbital angular momentum beam into a first beam and a second beam; the first beam is reflected at the first total reflection mirror 121 and the second beam is rotated 180 ° at the faraday reflection mirror 122 and reflected; the first beam and the second beam then re-enter the first beam splitter 120 to be coupled into a beam of light and exit.
The first total reflection mirror 121 is equidistant from the faraday mirror 122 and the first beam splitter 120; the first total reflection mirror 121 and the faraday reflection mirror 122 are both total reflection mirrors coated with a high reflection film; the splitting ratio of the first beam splitter 120 is 50:50.
The orbital angular momentum beam interference unit 13 includes a third lens 130, a second beam splitter 131, a plano-convex lens 132, a second total reflection mirror 133, and a fourth lens 134; the third lens 130 condenses the parallel light to become a divergent light beam; the plano-convex lens 132 and the second total reflecting mirror 133 interfere the diverged orbital angular momentum beam to obtain a desired orbital angular momentum interference beam; the second beam splitter 131 receives the light beam, and reflects the light beam to enter the fourth lens 134; the fourth lens 134 reconverges the divergent light into parallel light, resulting in a desired interference pattern and for measurement of topological charge values.
The splitting ratio of the second beam splitter 131 is 50:50; the second total reflection mirror 133 is a total reflection mirror plated with a high reflection film; the third lens 130 and the fourth lens 134 are converging lenses; the position of the plano-convex lens 132 is behind the focal point f of the third lens; the plano-convex lens 132 is closely connected to the second total reflection mirror 133.
Example 2
As shown in fig. 2, a method for measuring the topological charge value of an orbital angular momentum beam comprises the following steps:
s1: generating a continuous gaussian beam using a pump light source 10, the gaussian beam entering an orbital angular momentum beam generating unit 11;
s2: the gaussian beam entering the orbital angular momentum beam generating unit 11 passes through a lens group consisting of a first lens 110 and a second lens 111, and after passing through the lens group, the gaussian beam is expanded and collimated, and then passes through a polarizing plate 112, and the gaussian beam is converted into linearly polarized light; under the modulation of the computer PC114, the linearly polarized light enters the liquid crystal spatial light modulator SLM113 and is converted into a light beam with the following characteristics
Orbital angular momentum beams of the individual topological charges; the orbital angular momentum beam enters the orbital angular momentum beam coupling unit 12;
s3: the orbital angular momentum beam entering the orbital angular momentum beam coupling unit 12 is split into a first beam and a second beam at the first beam splitter 120, and the first beam and the second beam are coupled into a beam at the first beam splitter 120 again and exit through the reflection of the first total reflection mirror 121 and the rotation and reflection of the faraday reflection mirror 122, and enter the orbital angular momentum beam interference unit 13;
s4: the orbital angular momentum beam entering the orbital angular momentum beam interference unit 13 is changed from parallel light into divergent light at the third lens 130, then transmitted into the plano-convex lens 132 at the second beam splitter 131, the light refracted by the plano-convex lens 132 is reflected by the second total reflection mirror 133 at the bottom of the plano-convex lens 132 and then re-enters the plano-convex lens 132 to generate interference phenomenon, and then the interfered orbital angular momentum beam returns to the second beam splitter 131, is reflected into the fourth lens 134 at the second beam splitter 131 and is re-changed into parallel light, and leaves the orbital angular momentum beam interference unit 13;
s5: the orbital angular momentum beam leaving the orbital angular momentum beam interference unit 13 enters the optical detector 14 to obtain an interference pattern of the orbital angular momentum beam modulated by the system, so that the magnitude and the positive and negative of the topological charge value of the orbital angular momentum beam are respectively judged through the number of the interference maximum bright spots of the interference pattern and the rotation direction of the interference fringes.
In step S2, the computer PC114 projects the calculated hologram onto the liquid crystal spatial light modulator SLM113, and generates a desired orbital angular momentum beam by changing the liquid crystal array.
In step S4, the plano-convex lens 132 generates a desired interference phenomenon by a refraction phenomenon caused by a difference in refractive index of different media and an optical path difference caused by a difference in height between the cambered surface of the plano-convex lens 132 and the total reflection mirror.
The relation between the number n of the interference maximum bright spots and the topological charge value l is n= 2|l |, and the relation between the rotation direction of the interference fringes and the positive and negative values of the topological charge value is that clockwise rotation is positive and anticlockwise rotation is negative. Fig. 3 is a graph showing the result of the embodiment, from which it can be seen that there are 14 interference maximum bright spots, and the interference fringes rotate clockwise, so as to obtain an orbital angular momentum topology load value l= +7.
Example 3
As shown in fig. 2, a method for measuring the topological charge value of an orbital angular momentum beam comprises the following steps:
s1: generating a continuous gaussian beam using a pump light source 10, the gaussian beam entering an orbital angular momentum beam generating unit 11;
s2: the gaussian beams entering the orbital angular momentum beam generating unit 11 respectively pass through a lens group consisting of a first lens 110 and a second lens 111, and after passing through the lens group, the gaussian beams are expanded and collimated, and then pass through a polarizer 112, the gaussian beamsThe light beam is converted into linearly polarized light; under the modulation of the computer PC114, the linearly polarized light enters the liquid crystal spatial light modulator SLM113 and is converted into a light beam with the following characteristics
Orbital angular momentum beams of the individual topological charges; the orbital angular momentum beam enters the orbital angular momentum beam coupling unit 12;
s3: the orbital angular momentum beam entering the orbital angular momentum beam coupling unit 12 is split into a first beam and a second beam at the first beam splitter 120, and the first beam and the second beam are coupled into a beam at the first beam splitter 120 again and exit through the reflection of the first total reflection mirror 121 and the rotation and reflection of the faraday reflection mirror 122, and enter the orbital angular momentum beam interference unit 13;
s4: the orbital angular momentum beam entering the orbital angular momentum beam interference unit 13 is changed from parallel light into divergent light at the third lens 130, then transmitted into the plano-convex lens 132 at the second beam splitter 131, the light refracted by the plano-convex lens 132 is reflected by the second total reflection mirror 133 at the bottom of the plano-convex lens 132 and then re-enters the plano-convex lens 132 to generate interference phenomenon, and then the interfered orbital angular momentum beam returns to the second beam splitter 131, is reflected into the fourth lens 134 at the second beam splitter 131 and is re-changed into parallel light, and leaves the orbital angular momentum beam interference unit 13;
s5: the orbital angular momentum beam leaving the orbital angular momentum beam interference unit 13 enters the optical detector 14 to obtain an interference pattern of the orbital angular momentum beam modulated by the system, so that the magnitude and the positive and negative of the topological charge value of the orbital angular momentum beam are respectively judged through the number of the interference maximum bright spots of the interference pattern and the rotation direction of the interference fringes.
The method is applied to a system for measuring the topological charge value of the orbital angular momentum beam, and comprises a pumping light source 10, an orbital angular momentum beam generating unit 11, an orbital angular momentum beam coupling unit 12, an orbital angular momentum beam interference unit 13 and a light detector 14 which are connected in sequence;
the pump light source 10 generates a continuous gaussian beam; the orbital angular momentum beam generating unit 11 generates an orbital angular momentum beam carrying a desired topological charge; the orbital angular momentum beam coupling unit 12 is configured to split the orbital angular momentum beam and then couple the beam to obtain a coherent orbital angular momentum beam; the orbital angular momentum beam interference unit 13 performs secondary interference on the orbital angular momentum beam to obtain a required interference pattern; the light detector 14 observes the interference pattern to obtain magnitude and sign of the orbital angular momentum topology charge.
The orbital angular momentum beam generating unit 11 includes a first lens 110, a second lens 111, a polarizing plate 112, a liquid crystal spatial light modulator SLM113, and a computer PC114 connected in this order; the pump light source 10 is connected with a first lens 110, and the first lens 111 and a second lens 112 form a lens group to expand and collimate the input pump light; the polarizing plate 112 converts the gaussian beam into linearly polarized light; the computer PC114 delivers a computed hologram to the liquid crystal spatial light modulator SLM113, converting linearly polarized light into a desired orbital angular momentum beam.
The orbital angular momentum beam coupling unit 12 comprises a first beam splitter 120, a first total reflection mirror 121 and a faraday mirror 122; the first beam splitter 120 splits the passing orbital angular momentum beam into a first beam and a second beam; the first beam is reflected at the first total reflection mirror 121 and the second beam is rotated 180 ° at the faraday reflection mirror 122 and reflected; the first beam and the second beam then re-enter the first beam splitter 120 to be coupled into a beam of light and exit.
The first total reflection mirror 121 is equidistant from the faraday mirror 122 and the first beam splitter 120; the first total reflection mirror 121 and the faraday reflection mirror 122 are both total reflection mirrors coated with a high reflection film; the splitting ratio of the first beam splitter 120 is 50:50.
The orbital angular momentum beam interference unit 13 includes a third lens 130, a second beam splitter 131, a plano-convex lens 132, a second total reflection mirror 133, and a fourth lens 134; the third lens 130 condenses the parallel light to become a divergent light beam; the plano-convex lens 132 and the second total reflecting mirror 133 interfere the diverged orbital angular momentum beam to obtain a desired orbital angular momentum interference beam; the second beam splitter 131 receives the light beam, and reflects the light beam to enter the fourth lens 134; the fourth lens 134 reconverges the divergent light into parallel light, resulting in a desired interference pattern and for measurement of topological charge values.
The splitting ratio of the second beam splitter 131 is 50:50; the second total reflection mirror 133 is a total reflection mirror plated with a high reflection film; the third lens 130 and the fourth lens 134 are converging lenses; the position of the plano-convex lens 132 is behind the focal point f of the third lens; the plano-convex lens 132 is closely connected to the second total reflection mirror 133.
The same or similar reference numerals correspond to the same or similar components;
the positional relationship depicted in the drawings is for illustrative purposes only and is not to be construed as limiting the present patent;
it is to be understood that the above examples of the present invention are provided by way of illustration only and not by way of limitation of the embodiments of the present invention. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. Any modification, equivalent replacement, improvement, etc. which come within the spirit and principles of the invention are desired to be protected by the following claims.
Claims (8)
1. The system for measuring the topological charge value of the orbital angular momentum beam is characterized by comprising a pumping light source (10), an orbital angular momentum beam generating unit (11), an orbital angular momentum beam coupling unit (12), an orbital angular momentum beam interference unit (13) and a light detector (14) which are connected in sequence;
-said pump light source (10) generating a continuous gaussian beam; the orbital angular momentum beam generating unit (11) generates an orbital angular momentum beam carrying a desired topological charge; the orbital angular momentum beam coupling unit (12) is used for coupling after splitting the orbital angular momentum beam to obtain a coherent orbital angular momentum beam; the orbital angular momentum beam interference unit (13) performs secondary interference on the orbital angular momentum beam to obtain a required interference pattern; the optical detector (14) observes the interference pattern to obtain the magnitude and positive and negative of the orbital angular momentum topological charge value;
the orbital angular momentum beam coupling unit (12) comprises a first beam splitter (120), a first total reflection mirror (121) and a Faraday reflection mirror (122); the first beam splitter (120) splits the passing orbital angular momentum beam into a first beam and a second beam; the first beam is reflected at a first total reflection mirror (121), and the second beam is rotated 180 DEG at a Faraday reflection mirror (122) and reflected; the first light beam and the second light beam re-enter the first beam splitter (120) to be coupled into one light beam and then exit;
the orbital angular momentum beam interference unit (13) comprises a third lens (130), a second beam splitter (131), a plano-convex lens (132), a second total reflection mirror (133) and a fourth lens (134); the third lens (130) converges the parallel light to become a divergent light beam; the plano-convex lens (132) and the second total reflecting mirror (133) interfere the scattered orbital angular momentum light beams to obtain required orbital angular momentum interference light beams; the second beam splitter (131) receives the light beam and reflects the light beam to enter a fourth lens (134); the fourth lens (134) reconverges the divergent light into parallel light, resulting in the desired interference pattern and for measurement of the topological charge value.
2. The system for measuring an orbital angular momentum beam topology charge value according to claim 1, wherein the orbital angular momentum beam generating unit (11) comprises a first lens (110), a second lens (111), a polarizer (112), a liquid crystal spatial light modulator SLM (113) and a computer PC (114) connected in this order; the pumping light source (10) is connected with the first lens (110), the first lens (110) and the second lens (111) form a lens group, and the input pumping light is subjected to beam expansion and collimation; the polarizer (112) converts the Gaussian beam into linearly polarized light; the computer PC (114) delivers a computed hologram to the liquid crystal spatial light modulator SLM (113) for converting linearly polarized light into a desired orbital angular momentum beam.
3. The system for measuring orbital angular momentum beam topology charge of claim 2, wherein the first total reflection mirror (121) is equidistant from the faraday mirror (122) and the first beam splitter (120); the first total reflection mirror (121) and the Faraday reflection mirror (122) are total reflection mirrors plated with high reflection films; the first beam splitter (120) has a splitting ratio of 50:50.
4. A system for measuring orbital angular momentum beam topology charge according to claim 3, wherein the second beam splitter (131) has a splitting ratio of 50:50; the second total reflection mirror (133) is a total reflection mirror plated with a high reflection film; the third lens (130) and the fourth lens (134) are converging lenses; the plano-convex lens (132) is positioned after the focal point f of the third lens; the plano-convex lens (132) is closely connected with the second total reflection mirror (133).
5. A method of measuring orbital angular momentum beam topology charge of the system of measuring orbital angular momentum beam topology charge of claim 4, comprising the steps of:
s1: generating a continuous Gaussian beam by using a pumping light source (10), wherein the Gaussian beam enters an orbital angular momentum beam generating unit (11);
s2: the Gaussian beams entering the orbital angular momentum beam generating unit (11) respectively pass through a lens group consisting of a first lens (110) and a second lens (111), the Gaussian beams pass through the lens group to realize beam expansion and collimation, and then pass through a polaroid (112) to be converted into linearly polarized light; under the modulation of a computer PC (114), linearly polarized light enters a liquid crystal spatial light modulator SLM (113) and is converted into light with the following characteristics
Orbital angular momentum beams of the individual topological charges; the orbital angular momentum beam enters an orbital angular momentum beam coupling unit (12);
s3: the orbital angular momentum beam entering the orbital angular momentum beam coupling unit (12) is divided into a first beam and a second beam at the first beam splitter (120), and the first beam and the second beam are coupled into a beam at the first beam splitter (120) again to exit through the reflection of the first total reflection mirror (121) and the rotation and reflection of the Faraday reflection mirror (122), and enter the orbital angular momentum beam interference unit (13);
s4: the orbital angular momentum beam entering the orbital angular momentum beam interference unit (13) is changed into divergent light from parallel light at the third lens (130), then is transmitted into the plano-convex lens (132) at the second beam splitter (131), the light refracted by the plano-convex lens (132) is reflected by the second total reflection mirror (133) at the bottom of the plano-convex lens (132) and then re-enters the plano-convex lens (132) to generate interference phenomenon, and then the interfered orbital angular momentum beam returns to the second beam splitter (131), is reflected into the fourth lens (134) at the second beam splitter (131) and is changed into parallel light again, and leaves the orbital angular momentum beam interference unit (13);
s5: the orbital angular momentum beam leaving the orbital angular momentum beam interference unit (13) enters the optical detector (14) to obtain an interference pattern of the orbital angular momentum beam modulated by the system, so that the magnitude and the positive and negative of the topological charge value of the orbital angular momentum beam are respectively judged through the number of the interference maximum bright spots and the rotation direction of the interference fringes of the interference pattern.
6. The method according to claim 5, wherein in step S2, the computer PC (114) provides a calculation hologram to be projected onto the liquid crystal spatial light modulator SLM (113) to generate the desired orbital angular momentum beam by changing the liquid crystal array.
7. The method according to claim 6, wherein in the step S4, the plano-convex lens (132) generates the desired interference phenomenon by refraction phenomenon caused by different refractive indexes of different media and the optical path difference caused by the height difference between the cambered surface of the plano-convex lens (132) and the total reflection mirror.
8. The method of measuring an orbital angular momentum beam topology charge value of claim 7, wherein the number of interference maxima n is related to the topology charge value l by
The relation between the rotation direction of the interference fringes and the positive and negative values of the topological charge values is that clockwise rotation is positive and anticlockwise rotation is negative. />
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111620485.0A CN114295227B (en) | 2021-12-27 | 2021-12-27 | System and method for measuring orbital angular momentum beam topology charge value |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111620485.0A CN114295227B (en) | 2021-12-27 | 2021-12-27 | System and method for measuring orbital angular momentum beam topology charge value |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114295227A CN114295227A (en) | 2022-04-08 |
| CN114295227B true CN114295227B (en) | 2023-05-02 |
Family
ID=80969828
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111620485.0A Active CN114295227B (en) | 2021-12-27 | 2021-12-27 | System and method for measuring orbital angular momentum beam topology charge value |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114295227B (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103954367A (en) * | 2014-04-18 | 2014-07-30 | 河南科技大学 | Device for measuring fractional-order optical vortex topology charge values and measuring method thereof |
| CN109782197A (en) * | 2019-02-27 | 2019-05-21 | 中国科学院武汉物理与数学研究所 | Chip atom senses implementation method and its sensor |
| CN112461381A (en) * | 2020-11-10 | 2021-03-09 | 中国计量大学 | Device for measuring orbital angular momentum spectrum of vortex light beam |
| CN112484647A (en) * | 2020-11-18 | 2021-03-12 | 北京华卓精科科技股份有限公司 | Interferometer displacement measurement system and method |
| CN112865879A (en) * | 2020-12-31 | 2021-05-28 | 华南师范大学 | Spin-orbit angular momentum coupled hybrid entangled state generation system and method |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB201815712D0 (en) * | 2018-09-26 | 2018-11-07 | Imperial Innovations Ltd | Methods and apparatus for laser mode transformation |
-
2021
- 2021-12-27 CN CN202111620485.0A patent/CN114295227B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103954367A (en) * | 2014-04-18 | 2014-07-30 | 河南科技大学 | Device for measuring fractional-order optical vortex topology charge values and measuring method thereof |
| CN109782197A (en) * | 2019-02-27 | 2019-05-21 | 中国科学院武汉物理与数学研究所 | Chip atom senses implementation method and its sensor |
| CN112461381A (en) * | 2020-11-10 | 2021-03-09 | 中国计量大学 | Device for measuring orbital angular momentum spectrum of vortex light beam |
| CN112484647A (en) * | 2020-11-18 | 2021-03-12 | 北京华卓精科科技股份有限公司 | Interferometer displacement measurement system and method |
| CN112865879A (en) * | 2020-12-31 | 2021-05-28 | 华南师范大学 | Spin-orbit angular momentum coupled hybrid entangled state generation system and method |
Non-Patent Citations (1)
| Title |
|---|
| 量子保密通信与量子计算;郭邦红 等;《深圳大学学报理工版》;第第37卷卷(第第6期期);第551-558页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114295227A (en) | 2022-04-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP2023160825A (en) | Lidar system with solid-state spectral scanning | |
| US20200318949A1 (en) | Displacement sensor for frequency modulation continuous wave laser interference optical fiber and displacement detection method therefor | |
| US10962409B2 (en) | Method and system for measuring orbital angular momentum modes of photons based on spiral transformation | |
| CN102944312B (en) | Method for measuring partially coherent vortex light beam topological charge number | |
| CN109343077A (en) | A kind of LCD phased array ghost imaging system and its imaging method | |
| EP3211299A1 (en) | Illumination device | |
| WO2016111847A1 (en) | Method and apparatus for remote sensing using optical orbital angular momentum (oam) -based spectroscopy for detecting lateral motion of a remote object | |
| CN102289152B (en) | Optical system wave aberration detection device | |
| Gao et al. | Sorting and detecting orbital angular momentum states by using a Dove prism embedded Mach–Zehnder interferometer and amplitude gratings | |
| Henderson et al. | Free space adaptive optical interconnect at 1.25 Gb/s, with beam steering using a ferroelectric liquid-crystal SLM | |
| CN111130637B (en) | Measurement method and measurement system of photon spin-orbital angular momentum combined mode | |
| CN110837214A (en) | Scanning interference photoetching system | |
| CN115046482B (en) | Two-dimensional grating displacement measuring device | |
| CN109579694A (en) | A kind of the two degrees of freedom heterodyne grating interference measurement method and system of high tolerance | |
| CN110806680B (en) | Laser interference photoetching system | |
| KR101910980B1 (en) | Complex spatial light modulator and holographic 3D image display having the same | |
| CN101469976A (en) | Light wave interferometer apparatus | |
| CN103227408B (en) | Based on beam array phase control system and the method for leggy disturbance | |
| US11735885B2 (en) | Laser device | |
| CN103424878A (en) | Polarization light-splitting device | |
| CN114295227B (en) | System and method for measuring orbital angular momentum beam topology charge value | |
| Liu et al. | Design, implementation, and characterization of a hybrid optical interconnect for a four-stage free-space optical backplane demonstrator | |
| JPWO2019013320A1 (en) | Optical element and optical circuit | |
| US7187451B2 (en) | Apparatus for measuring two-dimensional displacement | |
| Niu et al. | Phase modulation characteristics analysis of liquid crystal spatial light modulator under oblique incidence |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| TR01 | Transfer of patent right | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20231225 Address after: 510663 room A105, first floor, ladder a, No. 11, panglv Road, Science City, Guangzhou high tech Industrial Development Zone, Guangdong Province Patentee after: Guangdong Yukopod Technology Development Co.,Ltd. Address before: 510898 No. 55, Zhongshan Avenue West, Tianhe District, Guangzhou, Guangdong Patentee before: SOUTH CHINA NORMAL University |