Continuous chaos few-mode laser based on degenerate cavity

Abstract

The utility model relates to the technical field of lasers, and provides a continuous chaos few-mode laser based on a degenerate cavity, which comprises a reflector, a gain medium, a first lens, a pinhole diaphragm, a second lens and an output coupling mirror which are coaxially arranged in sequence, the gain medium and the first lens form a combined lens, the reflecting mirror is arranged on a focal plane of the combined lens, the output coupling mirror is arranged on a focal plane of the second lens, and the combined lens is overlapped with the focal plane on one side close to the second lens. According to the invention, high power and high regulation degree of freedom can be achieved to meet the actual application requirements.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of lasers, in particular to a continuous chaos few-mode laser based on a degenerate cavity. BACKGROUND

[0002] A degenerate cavity generally refers to an optical resonator in which multiple optical modes with the same or similar resonant frequencies exist in the resonator under certain conditions. These modes can be mutually degenerate, that is, they exhibit the same physical characteristics to some extent, such as wavelength, phase, etc.

[0003] Chaos laser has important applications in the fields of secure communication, random number generation, laser radar, etc. due to its noise-like characteristics. Currently, the devices used to generate chaos laser are mainly semiconductor lasers with an external cavity feedback structure.

[0004] The existing chaos laser devices are mainly semiconductor lasers with an external cavity feedback structure, which have the problems of insufficient power and low control freedom.

[0005] Therefore, in view of the actual application requirements of free-space chaos optical communication, due to the inherent defects of traditional semiconductor lasers, it is urgent to develop new chaos light sources with high power, low cost, high complexity, and large control freedom.

[0006] CONTENT

[0007] The application aims to provide a continuous chaos few-mode laser based on a degenerate cavity, which can have high power and high control freedom to meet the actual application requirements.

[0008] The embodiment of the application is implemented by the following technical scheme: a continuous chaos few-mode laser based on a degenerate cavity, comprising a reflector, a gain medium, a first lens, a pin diaphragm, a second lens, and an output coupling mirror arranged coaxially in sequence; the gain medium and the first lens form a combined lens, and the reflector is arranged on the focal plane of the combined lens; the output coupling mirror is arranged on the focal plane of the second lens, and the focal plane of the combined lens and the side of the second lens is kept coincident.

[0009] Further, the output coupling mirror is provided with a rotating shaft at both ends, and the rotating shaft is connected with a support, one end of the rotating shaft is provided with a lock slot wheel; the support is provided with a mounting plate, the mounting plate is provided with a plug piece for clamping into the lock slot wheel for cooperation, the tail end of the plug piece is provided with a base, and the plug piece is provided with a reset spring sleeved between the mounting plate and the base.

[0010] Further, the bottom of the support is provided with a supporting column, the supporting column is provided with a driven gear, and the driven gear is connected with a driving gear.

[0011] Further, the support is a semi-circular ring structure.

[0012] Further, the mounting base is further provided with an adjusting sliding groove, and the reflecting mirror, the first lens, the second lens and the output coupling mirror are in sliding fit with the adjusting sliding groove.

[0013] Further, the pinhole aperture is arranged on a focal plane where the combined lens and the second lens coincide.

[0014] Further, the gain medium is a solid crystal.

[0015] The technical scheme of the embodiment of the application has at least the following advantages and beneficial effects:

[0016] 1. The application generates high-power laser through a solid gain medium, avoiding the size and power limitation of equipment caused by chip overheating when a semiconductor laser is used;

[0017] 2. The self-induced chaos is generated by using the beat frequency principle and mode interaction, without an external cavity feedback device, so that the overall volume is reduced, and the positions and angles of optical elements can be manually controlled, with higher flexibility;

[0018] 3. The degenerate resonant self-imaging and pinhole aperture mode limiting structure are used, so that the cavity can have similar Q values for transverse modes, thereby reducing the threshold power and obtaining good beam quality;

[0019] 4. Since the output power is large, compared with a semiconductor laser, an EDFA or other power amplifier device is not needed, and a spatial optical path output is used, so that the device can be directly connected to a free space optical communication system without the need for collimation and beam expansion equipment, thereby saving the operation cost. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical scheme of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the application, and therefore should not be regarded as a limitation on the scope, and for those skilled in the art, other related drawings can also be obtained without creative labor.

[0021] Figure 1 The structure schematic diagram of the continuous chaos few-mode laser based on the degenerate cavity provided by the embodiments of the application is shown;

[0022] Figure 2 The multi-angle adjustment structure schematic diagram of the output coupling mirror in the application is shown;

[0023] Figure 3 The top view of the mounting base in the application is shown;

[0024] Figure 4 Output light intensity diagram of the laser in the present application;

[0025] Figure 5 Power spectrum of the laser in the present application.

[0026] Figure: 1-mirror, 2-gain medium, 3-first lens, 4-small aperture diaphragm, 5-second lens, 6-output coupling mirror, 61-rotation shaft, 62-locking slot wheel, 7-bracket, 8-insert piece, 81-base, 9-mounting plate, 10-return spring, 11-support column, 12-driven gear, 13-driving gear, 14-mounting base plate, 141-adjusting sliding groove. DETAILED DESCRIPTION

[0027] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some but not all of the embodiments of the present application. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0028] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present application.

[0029] It should be noted that: similar reference numbers and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0030] EMBODIMENTS

[0031] The following will be further illustrated in conjunction with specific embodiments, with reference to Figures 1-3As shown, the embodiment is a continuous chaos few-mode laser based on a degenerate cavity, comprising a mirror 1, a gain medium 2, a first lens 3, a pinhole diaphragm 4, a second lens 5 and an output coupling mirror 6 arranged coaxially in sequence; the gain medium 2 and the first lens 3 form a combined lens, and the mirror 1 is arranged on the focal plane of the gain medium 2 and the first lens 3, the output coupling mirror 6 is arranged on the focal plane of the second lens 5, and the focal plane of the combined lens and the side of the second lens 5 keeps coinciding; specifically, a mathematical model of the degenerate cavity is constructed by using the ABCD transfer matrix, it is assumed that the focal length of the thermal lens generated by the gain medium 2 is f1, the focal lengths of the first lens 3 and the second lens 5 are f2 and f3 respectively, the distance between the mirror 1 and the gain medium 2 is l1, the distance between the gain medium 2 and the first lens 3 is l2, the distance between the first lens 3 and the pinhole diaphragm 4 is l3, the distance between the pinhole diaphragm 4 and the second lens 5 is l4, and the distance between the second lens 5 and the output coupling mirror 6 is l5, and the forward loop matrix of the whole system along the coaxial positive direction is:

[0032]

[0033] The backward loop matrix of the whole system along the coaxial negative direction is:

[0034]

[0035] The loop matrix of the system is:

[0036] The distance between each optical element is adjusted so that A=D=1 of the ABCD matrix of the system, thereby satisfying the degenerate condition, and in order to obtain the highest mode degeneracy, B=C=0 of the system.

[0037] From the perspective of geometric optics, any light ray of the system returns to the original position after experiencing a single loop, and from the perspective of physical optics, there are numerous transverse modes degenerate under each longitudinal mode of the system, and all the transverse modes have the same Q value.

[0038] The mirror 1 and the output coupling mirror 6 form a resonant cavity, which prolongs the length of the gain medium 2 by reflecting the light back and forth, improves the photon energy density in the cavity, and finally makes the photons realize stimulated radiation. The gain medium 2 has an energy level structure to generate stimulated radiation and provides amplification to photons. The thermal lens equivalent to the gain medium 2 and the first lens 3 form a combined lens together with the second lens 5 to form a self-imaging system. The pinhole diaphragm 4 acts as a transverse mode selector, increases the loss of high-order transverse modes, reduces the order of modes for transverse modes with the same Q value, makes the laser be in a few-mode state with a mode number of 2-4, and reduces the beam divergence angle.

[0039] Reference Figure 2As shown, the output coupling mirror 6 in the embodiment has a rotating shaft 61 at both ends, and the rotating shaft 61 is connected with a support 7, and one end of the rotating shaft 61 is provided with a lock slot wheel 62; the support 7 is provided with a mounting plate 9, and the mounting plate 9 is penetrated by a plug 8 used for clamping into the lock slot wheel 62 for cooperation, and the tail end of the plug 8 is provided with a base 81, and the plug 8 is sleeved with a reset spring 10 clamped between the mounting plate 9 and the base 81. And the bottom of the support 7 is provided with a supporting column 11, and the supporting column 11 is installed with a driven gear 12, and the driven gear 12 is engaged with a driving gear 13; specifically, by setting the rotating shaft 61 and the supporting column 11, the rotating shaft 61 is located horizontally, and the supporting column 11 is located vertically, the output coupling mirror 6 is rotated around the rotating shaft 61, and the plug 8 is clamped into the groove of the lock slot wheel 62 by using the elastic force of the reset spring 10 for locking, so as to adjust the inclination angle of the direction; then the driving gear 13 is manually driven to drive the driven gear 12 and the supporting column 11 to rotate to adjust the angle position of the output coupling mirror 6 in the vertical direction, so that the cavity loses the rotational symmetry of the plurality of elements in the coaxial direction, the transverse mode degeneracy is generated in the spectral structure, and the transverse mode beat frequency ω b is generated b , which interacts with the relaxation oscillation frequency ω r of the laser, adjusts the inclination degree, so that ω r < ω b < 2ω r , and the laser output light intensity presents a noise-like phenomenon as Figure 4 shown, at this time the system is in a chaotic state. The spectral structure is observed by using a frequency spectrometer, and the power spectrum does not have obvious relaxation oscillation peaks, and presents a flat power spectrum as Figure 5 shown.

[0040] In order to facilitate the contact adjustment of the output coupling mirror 6 to the inclination angle, the support 7 can be designed as a semi-circular ring structure.

[0041] As shown in Figure 1 and Figure 3 , the embodiment further includes a mounting bottom plate 14, and the mounting bottom plate 14 is provided with an adjusting sliding groove 141, and the reflecting mirror 1, the first lens 3, the second lens 5 and the output coupling mirror 6 are slidably matched with the adjusting sliding groove 141; in order to facilitate the adjustment of the linear distance between the elements to reach the correct working position, the bottom block of the reflecting mirror 1, the first lens 3 and the like is clamped into the adjusting sliding groove 141 for movement.

[0042] The pinhole diaphragm 4 is arranged on the focal plane where the combined lens and the second lens 5 coincide, and the pinhole diaphragm 4 can be a circular diaphragm, a square diaphragm and the like structure, the circular aperture is 0.5-1mm, and the square aperture length is 0.75mm and the width is 0.75mm.

[0043] It is worth mentioning that the gain medium 2 adopts a solid structure, and Nd:YAG, Nd:YO4, Nd:YLF and the like Nd3+ Doped gain medium, concentration 0.8at% - 1.2at%, thickness 1 - 3 mm, in cylindrical or square configuration.

[0044] The above merely provides preferred embodiments of the present application but is not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A degenerate cavity based continuous chaotic few-mode laser, characterized in that: The application relates to a laser device, which comprises a reflector (1), a gain medium (2), a first lens (3), a pinhole diaphragm (4), a second lens (5) and an output coupling mirror (6) arranged in sequence in a coaxial manner. The gain medium (2) and the first lens (3) form a combined lens, the reflector (1) is arranged on the focal plane of the combined lens of the gain medium (2) and the first lens (3), the output coupling mirror (6) is arranged on the focal plane of the second lens (5), and the combined lens and the focal plane next to the second lens (5) are kept in coincidence.

2. The degenerate cavity based continuous chaos few-mode laser of claim 1, wherein: The output coupling mirror (6) is provided with a rotating shaft (61) at two ends, the rotating shaft (61) is connected with a support (7), one end of the rotating shaft (61) is provided with a lock slot wheel (62), and the support (7) is provided with a mounting plate (9). The mounting plate (9) is provided with an insertion piece (8) for clamping the lock slot wheel (62) for cooperation, the tail end of the insertion piece (8) is provided with a base (81), and the insertion piece (8) is sleeved with a reset spring (10) clamped between the mounting plate (9) and the base (81).

3. The degenerate cavity based continuous chaos few-mode laser of claim 2, wherein: The bottom of the support (7) is provided with a supporting column (11), the supporting column (11) is mounted with a driven gear (12), and the driven gear (12) is connected with a driving gear (13) in a meshing mode.

4. The degenerate cavity based continuous chaos few-mode laser of claim 2, wherein: The support (7) is a semicircular ring structure.

5. The degenerate cavity based continuous chaos few-mode laser of claim 1, wherein: The mounting bottom plate (14) is further provided with an adjusting sliding groove (141), and the reflector (1), the first lens (3), the second lens (5) and the output coupling mirror (6) are in sliding cooperation with the adjusting sliding groove (141).

6. The degenerate cavity-based continuous chaos few-mode laser of claim 1, wherein: The pinhole diaphragm (4) is arranged on the focal plane where the combined lens and the second lens (5) are coincident.

7. The degenerate cavity-based continuous chaos few-mode laser of claim 1, wherein: The gain medium (2) is a solid crystal.

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