CN100481655C - Laser resonant cavity fast cavity-regulating method based on random parallel optimization algorithm - Google Patents

Abstract

This invention discloses a method for adjusting laser resonant cavities quickly based on a random parallel optimized algorithm, which controls position and angle of each cavity mirror in a resonant cavity using a random parallel optimizing algorithm so as to get a global extremum of the beam quality evaluation function, and the system is composed of a laser, two resonant cavity mirrors, two tilt couple mirrors, a lens, a sensor, a device with a random parallel optimizing algorithm and a position/angle controller.

Description

Laser resonant cavity fast cavity-regulating method based on random parallel optimization algorithm

Technical field

The present invention relates to a kind of method of laser resonant cavity fast cavity-regulating, especially a kind of method of utilizing random parallel optimization algorithm to realize laser resonant cavity fast cavity-regulating.

Background technology

Accurately whether the power output of laser, beam quality resonant cavity school accent have much relations, and the misalignment rate of chamber mirror will cause the decline of Laser Output Beam quality and power output, even laser can't be worked.This requirement is made fast reaction to cavity mirror misalignment, in time debugging.

Existing cavity adjustment method one is to utilize the interference fringe interpretation, the 2nd, utilize in the course of work monitoring to optical power distribution.The experience composition of said method is many, and the precision of adjusting depends on staff's perceptual experience to a great extent, is difficult in the system of more complicated know the decline of output beam quality specifically by which minute surface is caused, therefore transfers the chamber not accurate enough in time.And the number and the degree of freedom of resonant cavity lumen mirror are a lot, and it is unpractical only carrying out manual debugging according to staff's experience, need effective method more.

Along with the appearance and the development of computer, it is the inexorable trend of transferring the chamber technical development that the area of computer aided of resonant cavity is regulated.Open and grasp equalization (Chinese laser, 1992 the 7th phases) utilize infrared photoelectric detector observation light pulse envelope waveform, obtain the long misalignment rate in chamber, make chamber progress go into the operate as normal field with microcomputer-controlled step motor, and then long the adjusting automatically in chamber made it working stability with the system controlled by computer electrostretch device.Liu Yan etc. (light laser and the particle beams, 2003 the 3rd phases) utilize position transducer to measure chamber mirror offset information when the resonant cavity cavity mirror misalignment amount of Chemical oxygen-iodine laser is measured and studied, and obtain offset data through analog-to-digital conversion again.This method requires than higher sensor accuracy and experimental situation, and the imbalance number of degrees of freedom, that can measure is also less.Hu Yahong etc. (photon journal, the 7th phase of calendar year 2001) carry out image processing by the output facula to resonant cavity, calculate the energy excursion and the offset of hot spot, and the counter relation of releasing mirror inclination angle, chamber and facula deviation amount is adjusted resonant cavity in real time.This method can realize transferring automatically and steadily the chamber, but only for the adjustment at the angle misalignment rate, certain limitation is arranged.

Summary of the invention

The technical problem to be solved in the present invention is: overcome the deficiencies in the prior art, proposition utilizes random parallel optimization algorithm to realize the method for resonant cavity fast cavity-regulating, can realize fast velocity modulation chamber in the short period of time, experimental situation and instrument and equipment there is not specific (special) requirements, need not phase place sensing equipment and special software for calculation, simplify system's composition, can adjust all the chamber mirrors in the resonant cavity simultaneously, shortened the preceding stand-by period of laser bright dipping.

Technical solution of the present invention is: utilize position, the angle of each chamber mirror in the random parallel optimization algorithm control resonant cavity, make to act on Position Control information of voltage on the position/angles controller and the beam quality evaluation function of angle control information of voltage is obtained global extremum.Whole system is by laser 1, resonator mirror 2,3, and inclination coupling mirror 4,5, lens 6, transducer 7, random parallel optimization algorithm is realized device 8, position/angles controller 9 is formed.

The laser kind is not limit, and can be the laser of any kind such as He-Ne laser; The resonant cavity kind is not limit, and is stable cavity, can be unsteady cavity yet, and the number of chamber endoscope is not limit; Transducer can be imageing sensors such as CCD, cmos device, also can be photoelectric sensors such as photocell; Random parallel optimization algorithm realizes that device can be a computer, also can be integrated circuit (IC) chip; The position/angles controller can be that any kind such as piezoelectric ceramic, electromagnetism expansion bend can be used to regulate the device of chamber mirror position/angles.The first inclination coupling mirror (4) and the second inclination coupling mirror (5) are the total reflective mirrors that certain pore size is arranged.

The implementation procedure in the fast velocity modulation of the present invention chamber is as follows:

1, tentatively adjusts chamber mirror 2,3;

2, the resonant cavity emitting laser is coupled out outside the chamber by inclination coupling mirror 4,5, converges on the transducer 7 through lens 6;

3, transducer 7 reaches random parallel optimization algorithm with the information that obtains and realizes device 8;

4, reach position/angles controller 9 through controlling information of voltage after 8 computings;

5, system repeats above-mentioned steps 2,3,4, and through after the regular hour, random parallel optimization algorithm is realized the control information of voltage of device 8 computings generation with invariable, shows that this moment, resonant cavity mixed up.

Random parallel optimization algorithm realizes that device produces the process of controlling information of voltage and is:

At first define an evaluation function J (u ₁, u ₂..u _N, v ₁, v ₂... v _N), (u ₁, u ₂..u _N), (v ₁, v ₂... v _N) being respectively the Position Control information of voltage and the angle control information of voltage that act on the position/angles controller, N is the chamber mirror number that contains in the resonant cavity.u _i, v _i(j=1 ... N) all be three-dimensional vector, the adjustment amount of control chamber mirror j position (x, y, z direction), angle (driftage, pitching, roll angle) in whole space.Every function that meets the following conditions all can be used as the evaluation function in the random parallel optimization algorithm: when resonant cavity mixed up, J got global extremum.

When time step k, random parallel optimization algorithm realizes that device 8 initiatively applies random perturbation voltage to position/angles controller 9

Be the stochastic variable of obeying statistical law, satisfy $\⟨{\mathrm{\δu}}_j^k{\mathrm{\δu}}_i^k\⟩={\mathrm{\σ}}_1^2{\mathrm{\δ}}_{\mathrm{ji}},$ $\⟨{\mathrm{\δv}}_j^k{\mathrm{\δv}}_i^k\⟩={\mathrm{\σ}}_2^2{\mathrm{\δ}}_{\mathrm{ji}}$ And $\⟨{\mathrm{\δu}}_j^k\⟩=0,$ $\⟨{\mathrm{\δv}}_j^k\⟩=0,$ δ wherein _JiIt is the Kronecker symbol.Random perturbation voltage can be produced by computer, also can be that integrated circuit (IC) chip produces.

Behind random perturbation voltage, random parallel optimization algorithm is realized the evaluation function J variable quantity that device 8 brings because of random perturbation at this moment according to the information calculations that receives transducer 7 transmission:

${\mathrm{\δJ}}^k=J(u_1^k+{\mathrm{\δu}}_1^k,...u_j^k+{\mathrm{\δu}}_j^k,...u_N^k+{\mathrm{\δu}}_N^k,v_1^k+{\mathrm{\δv}}_1^k,...v_j^k+{\mathrm{\δv}}_j^k,...u_N^k+{\mathrm{\δv}}_N^k)$

$-J(u_1^k,...u_j^k,...u_N^k,v_1^k,...v_j^k,...v_N^k)$

Upgrade (u according to evaluation function J variable quantity ₁... u _j... u _N, v ₁... v _j... v _N), act on the control information of voltage of position/angles controller 9 constantly as next $(u_1^{k+1},...u_j^{k+1},...u_N^{k+1},v_1^{k+1},...v_j^{k+1},...v_N^{k+1}),$ Replacement criteria is:

$u_j^{k+1}=u_j^k-{\mathrm{\γ}}_1{\mathrm{\δJ}}^k{\mathrm{\δu}}_j^k$

$v_j^{k+1}=v_j^k-{\mathrm{\γ}}_2{\mathrm{\δJ}}^k{\mathrm{\δv}}_j^k$

γ in the following formula ₁, γ ₂Be the weight coefficient vector of artificial definition, decide according to the practical operation situation of system.

By applying random perturbation voltage to position/angles controller 9, random parallel optimization algorithm realizes that device 8 calculates evaluation function J variable quantity in real time, can bring in constant renewal in the control information of voltage that is applied on the position/angles controller 9, J gets global optimum until evaluation function, the situation that corresponding resonant cavity mixes up.So just realized fast velocity modulation chamber.

Adopt the present invention can reach following technique effect:

1, the present invention proposes a kind of quick cavity adjustment method of laser resonant cavity, it transfers the chamber by area of computer aided, has avoided the blindness and the contingency of existence in the work of traditional people's wage adjustment chamber, has saved the needed operating time of accent chamber greatly, has improved operating efficiency.

2, the quick cavity adjustment method of the present invention's proposition is simple, and experimental situation and instrument and equipment are not had specific (special) requirements, does not need to carry out complicated misalignment rate and calculates, and does not also need complicated phase detection instruments such as striped interpretation equipment, has simplified the formation of cavity-adjusting system.

3, the quick cavity adjustment method of the present invention's proposition is applied widely, is applicable to the accent chamber process of any kind resonant cavity.

4, the quick cavity adjustment method of the present invention's proposition can be regulated position, the angle misalignment rate of all chamber mirrors in the resonant cavity simultaneously.

Description of drawings

Fig. 1 is a system configuration principle schematic of the present invention

Embodiment

As shown in Figure 1, whole system is by laser 1, resonator mirror 2,3, and inclination coupling mirror 4,5, lens 6, transducer 7, random parallel optimization algorithm is realized device 8, position/angles controller 9 is formed.At first tentatively adjust chamber mirror 2,3; The resonant cavity emitting laser is coupled out outside the chamber by inclination coupling mirror 4,5, converges on the transducer 7 through lens 6; Transducer 7 reaches random parallel optimization algorithm with the information that obtains and realizes device 8; Reach position/angles controller 9 through controlling information of voltage after 8 computings; System repeats said process, and through after the regular hour, random parallel optimization algorithm is realized the control information of voltage of device 8 computings generation with invariable, and evaluation function J gets global extremum, shows that this moment, resonant cavity mixed up.

Claims (4)

1, laser resonant cavity fast cavity-regulating method based on random parallel optimization algorithm, it is characterized in that utilizing the position of each chamber mirror in the random parallel optimization algorithm control resonant cavity, angle, make and to act on Position Control information of voltage on the position/angles controller and the beam quality evaluation function of angle control information of voltage is obtained global extremum, whole system is by laser (1), resonator mirror (2,3), the first inclination coupling mirror (4) and the second inclination coupling mirror (5), lens (6), transducer (7), random parallel optimization algorithm is realized device (8), position/angles controller (9) is formed, and the implementation procedure in fast velocity modulation chamber is as follows:

1) tentatively adjusts resonator mirror (2,3);

2) the resonant cavity emitting laser is coupled out outside the chamber by the first inclination coupling mirror (4) and the second inclination coupling mirror (5), converges on the transducer (7) through lens (6);

3) transducer (7) reaches random parallel optimization algorithm with the information that obtains and realizes device (8);

4) reach position/angles controller (9) through controlling information of voltage after the computing of random parallel optimization algorithm realization device (8);

5) system repeats above-mentioned steps 2), 3), 4), through after the regular hour, random parallel optimization algorithm realizes that control information of voltage that device (8) computing produces with invariable, shows that this moment, resonant cavity mixed up.

2, the laser resonant cavity fast cavity-regulating method based on random parallel optimization algorithm as claimed in claim 1 is characterized in that the first inclination coupling mirror (4) and the second inclination coupling mirror (5) are the total reflective mirrors that certain pore size is arranged.

3, the laser resonant cavity fast cavity-regulating method based on random parallel optimization algorithm as claimed in claim 1 is characterized in that described transducer (7) is a kind of in CCD, cmos device or the photocell transducer.

4, the laser resonant cavity fast cavity-regulating method based on random parallel optimization algorithm as claimed in claim 1 is characterized in that random parallel optimization algorithm realization device (8) can be a computer, also can be integrated circuit (IC) chip.

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