CN207587399U - A kind of device that optical eddy is generated using coherent laser array - Google Patents

Abstract

The utility model relates to a device for generating an optical vortex by using a coherent laser array. The device utilizes a He‑Ne laser to generate a Gaussian beam of stable intensity. The Gaussian beam enters the beam expander after being reflected by the mirror. The beam expander expands the radius of the incident beam to r and enters the microlens array. The incident beam is split into 6 sub-beams uniformly distributed in the angular direction under the action of the microlens array and enters the spatial light modulator. The spatial light modulator is controlled by computer A. The incident sub-beams obtain different initial phases under the action of the spatial light modulator, and the phase difference between adjacent sub-beams is πm/3, where m is the topological charge. The light beam array emitted from the spatial light modulator converges on the CCD detector at the focal plane of the lens after free transmission. The CCD detector records the light intensity data of the outgoing beam and transmits it to computer B. The utility model has the advantages that an optical vortex with dynamically adjustable topological charge values can be realized. In the long-distance transmission environment, it still has good topological charge stability.

Description

A device for generating optical vortex using coherent laser array

technical field

The utility model provides a device for generating an optical vortex by using a coherent laser array, which belongs to the field of optical information control.

Background technique

Laser arrays have been extensively studied due to their potential applications in high-energy weapons and atmospheric optical communications. The sub-beams in the radial or rectangular symmetrical distribution in the laser array are coherently superimposed or non-coherently superimposed under phase-locked and non-phase-locked conditions. The superimposed light field can maintain stable light intensity distribution and high power in long-distance transmission. At present, the research on laser array is mainly focused on light intensity manipulation, and the research on its phase information is not enough.

An optical vortex refers to a coherent light field with a helical phase structure. The helical phase structure makes the photons of the light field have orbital angular momentum. The orbital angular momentum carried by the vortex light field is quantitatively described by the topological charge value of the vortex phase. The value of the topological charge of the optical vortex is an integer, and different values of the topological charge represent different orbital angular momentums. Among them, the orbital angular momentum follows the principle of momentum conservation during the transmission process. Using vortex light as the carrier of optical signals, in addition to using traditional methods such as amplitude, polarization, and frequency to carry information, it can also use topological charge values to describe information. Therefore, vortex light has a larger information bandwidth. For this reason, the generation method and device of the optical vortex have practical significance. The current methods and devices for generating optical vortices mainly use a spiral phase plate or a spatial light modulator to directly modulate the phase of the incident light field, so as to achieve the purpose of having a vortex phase in the outgoing light field. However, the optical vortex produced by this method has a narrow dynamic range of topological charge values, and the light intensity of the outgoing light field is small, so it is unstable to disturbances.

In order to solve the above-mentioned technical problems, the utility model uses a microlens array to form a laser array light source, controls the spatial distribution and initial phase of each sub-beam in the array, and realizes an optical vortex with dynamically adjustable topological charge values. The utility model has the characteristics of large modulation range of topological charges and stable output light intensity. The optical vortex produced by the utility model has better topological charge stability in the long-distance transmission environment.

Contents of the invention

The utility model provides an optical vortex generating device with a large modulation range of topological charge and stable output light intensity. The device uses a He-Ne laser to generate a Gaussian beam with stable intensity, and the Gaussian beam is reflected by a mirror and enters a beam expander. Under the action of the beam expander, it expands into a light spot with a radius of r, and enters the microlens array. The microlens array splits the incident light into six sub-beams that are uniformly distributed in the angular direction. The outgoing light beam enters a spatial light modulator coaxially close to the microlens array. The spatial light modulator is connected to and controlled by computer A. Under the action of the spatial light modulator, the sub-beams emitted from the microlens array obtain different initial phases, wherein the phase difference between adjacent beams is πm/3, and m is a topological charge. The light beam array emitted from the spatial light modulator converges at the focal plane of the lens after free transmission. The CCD detector placed at the focal plane of the lens detects the light intensity information of the optical vortex and transmits it to the computer B. The utility model uses a microlens array to form a laser array light source, controls the spatial distribution and initial phase of each sub-beam in the array, and realizes an optical vortex with dynamically adjustable topological charge values through the action of a spatial light modulator. The optical vortex produced by the utility model has a large modulation range of topological charge, stable output light intensity, and better stability of topological charge in a long-distance transmission environment.

Description of drawings

Below in conjunction with accompanying drawing and embodiment this utility model is described further.

Fig. 1 is a schematic diagram of a device for generating an optical vortex using a coherent laser array.

In the figure: 1. He-Ne laser, 2. Mirror, 3. Beam expander, 4. Microlens array, 5. Spatial light modulator, 6. Computer A, 7. Lens, 8. CCD detector, 9 .Computer B

Figure 2 is a schematic diagram of the arrangement of the microlens array.

In the figure: 1-6. Microlens.

Detailed ways

Below in conjunction with accompanying drawing and specific embodiment the utility model is described in further detail:

The working steps of the device shown in Figure 1 are as follows:

1. The He-Ne laser (1) produces a Gaussian beam with stable intensity and enters the mirror (2); the reflected beam of the mirror (2) enters the beam expander (3); the beam expander (3) Expand the radius of the incident beam to r; the beam emitted from the beam expander (3) enters the microlens array (4); the microlens array (4) splits the incident beam into 6 uniform beams in the angular direction distributed sub-beams; the 6 sub-beams emitted from the microlens array (4) enter the spatial light modulator (5) coaxially placed close to the microlens array (4); the spatial light modulator (5) and The computer A (6) is connected; and controlled by the computer A (6); under the action of the spatial light modulator (5), the sub-beams emitted from the microlens array (4) obtain different initial phases, and the adjacent sub-beams The initial phase difference is πm/3, m is a non-zero integer; the beam array emitted from the spatial light modulator (5) is freely transmitted and then converged by the lens (7) to the CCD detector (8) at the focal plane; the The incident light at the CCD detector (8) has an optical vortex with a topological charge of m; the CCD detector (8) records the light intensity data of the incident beam and transmits it to the computer B (9);

Figure 2 shows a schematic diagram of the microlens array (4):

1. The microlenses (1)-(6) in Figure 2 are exactly the same, and the radius of each microlens is 0.33r; the microlenses (1)-(6) are arranged in a closed circular ring in a coplanar, adjacent and tangent manner .

Claims (2)

1. A device that utilizes a coherent laser array to generate an optical vortex, structurally at least including a He-Ne laser (1), a mirror (2), a beam expander (3), a microlens array (4), a spatial light Modulator (5), computer A (6), lens (7), CCD detector (8), computer B (9), characterized in that: He-Ne laser (1) produces Gaussian beam with stable intensity, and enters mirror (2); the reflected beam of the mirror (2) enters the beam expander (3); the beam expander (3) expands the radius of the incident beam to r; from the beam expander (3) The outgoing beam enters the microlens array (4); the microlens array (4) splits the incident light into 6 sub-beams uniformly distributed in the angular direction; the 6 sub-beams exiting from the microlens array (4) Enter the spatial light modulator (5) coaxially placed close to the microlens array (4); the spatial light modulator (5) is connected to the computer A (6); and controlled by the computer A (6); in the spatial light Under the action of the modulator (5), the sub-beams emitted from the microlens array (4) obtain different initial phases, and the initial phase difference between adjacent sub-beams is πm/3, where m is a non-zero integer; from the spatial light modulator (5) After the outgoing beam array is freely transmitted, it is converged by the lens (7) to the CCD detector (8) at the focal plane; the incident light at the CCD detector (8) has an optical vortex with a topological charge of m ; The CCD detector (8) records the light intensity data of the incident beam and transmits it to the computer B (9). 2. A device for generating an optical vortex using a coherent laser array according to claim 1, characterized in that: the microlens array (4) consists of 6 circular microlenses with a radius of 0.33r that are coplanar and adjacent to each other. Arranged in a closed circular ring in a tangential manner; the phase modulation of the spatial light modulator (5) is evenly divided into 6 areas within the polar angle range; each polar angle area of the spatial light modulator (5) is in contact with the micro Each microlens of the lens array (4) is in one-to-one correspondence, so that sub-beams emitted from the microlens array (4) enter different polar angle regions of the spatial light modulator (5).