CN100549753C - ADAPTIVE OPTICS SYSTEMS based on self-reference wavefront sensor and continuous surface deformable mirror - Google Patents

Abstract

ADAPTIVE OPTICS SYSTEMS based on self-reference wavefront sensor and continuous surface deformable mirror, by wave-front corrector, self-reference wavefront sensor and industrial computer based on the Mach-Zehnder interferometric method are formed, light beam is at first by behind the wave-front corrector, reflection enters self-reference wavefront sensor based on the Mach-Zehnder interferometric method, the wavefront information that detects based on the self-reference wavefront sensor of Mach-Zehnder interferometric method through a matrix operation of industrial computer after directly output control voltage to wave-front corrector and carry out closed loop.Wave-front corrector adopts the separate unit continuous surface deformable mirror that response speed is faster arranged, wave front detector utilization principle of interference, have higher spatial resolution and detection accuracy, can greatly improve wavefront correction performance like this based on the ADAPTIVE OPTICS SYSTEMS of interfering wave front detector, enlarged the application of this ADAPTIVE OPTICS SYSTEMS, superiority is obvious.

Description

ADAPTIVE OPTICS SYSTEMS based on self-reference wavefront sensor and continuous surface deformable mirror

Technical field

The present invention relates to a kind of ADAPTIVE OPTICS SYSTEMS, particularly a kind of continuous surface deformable mirror adaptive optics corrective system based on self-reference wavefront sensor.

Background technology

At present among ADAPTIVE OPTICS SYSTEMS, the application of Hartmann wave front sensor is comparatively extensive, and when the corrugated of incident bore increases, survey the sub-number of perforations that needs to increase the Shack-Hartmann Wavefront sensor, and the CCD number of pixels of each corresponding some in sub-aperture, therefore on the CCD target surface, need more pixel, the CCD camera has been proposed higher requirement.Each pixel in based on the ADAPTIVE OPTICS SYSTEMS of self-reference wavefront sensor on the CCD target surface can be regarded a sub-aperture as, each pixel gets final product the part of direct corresponding wavefront like this, when incident corrugated bore increases, compare with the Shack-Hartmann Wavefront sensor, can effectively reduce the pixel count of CCD camera, and effectively improve the spatial resolution of Wavefront detecting.In ADAPTIVE OPTICS SYSTEMS based on the self-reference wavefront sensor of Mach-Zehnder interferometric method, the distorting lens corrector of continuous surface can be made into and be complementary corresponding with Wavefront sensor CCD pixel, the wavefront information that arrives by wave front detector do that front wave solutions is twined and conjugation after, just directly in the controlled deformation mirror with the corresponding driver element of CCD pixel.At article " High Order; Reconstructor-Free Adaptive Optics for 6-8meter class Telescopes " Maud Langlois, Roger Angel, MichaelLloyd-Hart, adopted the liquid crystal spatial modulator as wave-front corrector among the Venice 2001Beyond Conventional Adaptive Optics, it is not high that but the liquid crystal spatial modulator itself has the efficiency of light energy utilization, chromatic dispersion is serious, response speed waits shortcoming slowly, has seriously influenced the application of this ADAPTIVE OPTICS SYSTEMS when atmospheric disturbance.What therefore in the present invention, its corrector had adopted that material such as PZT, PMN become separate type just can well overcome above shortcoming.

Summary of the invention

Technology of the present invention is dealt with problems and is: overcome the deficiencies in the prior art, a kind of efficiency of light energy utilization height is provided, the ADAPTIVE OPTICS SYSTEMS that response speed is fast based on self-reference wavefront sensor and continuous surface deformable mirror, in this ADAPTIVE OPTICS SYSTEMS, wave front detector has adopted the self-reference wavefront sensor based on interferometric method, has promoted precision and spatial resolution that the corrugated is surveyed.

One of technical solution of the present invention is: based on the ADAPTIVE OPTICS SYSTEMS of self-reference wavefront sensor and continuous surface deformable mirror, it is characterized in that: by wave-front corrector, self-reference wavefront sensor and industrial computer based on the Mach-Zehnder interferometric method are formed, light beam is at first by behind the wave-front corrector, reflection enters self-reference wavefront sensor based on the Mach-Zehnder interferometric method, the wavefront information that detects based on the self-reference wavefront sensor of Mach-Zehnder interferometric method through a matrix operation of industrial computer after directly output control voltage to wave-front corrector and carry out closed loop.

Described wave-front corrector adopts the continuous surface deformable mirror of the separate unit with very fast response speed to constitute.

In the described self-reference wavefront sensor based on the Mach-Zehnder interferometric method, wherein one road light carries out pin hole filtering, and filtered light beam is as the reference light beam; Another road light path is constant substantially, does the decay back and interferes with reference beam, has obtained two width of cloth interference images, adopts two CCD to gather simultaneously, and outputs in the industrial computer synchronously.

In the described self-reference wave front detector, can in reference path, add phase shifter, conveniently obtain the multi-frame interferometry image and repeatedly survey based on the Mach-Zehnder interferometric method.

The unit cell arrangement of described continuous surface deformable mirror and number of unit and arrange based on detected pixel in two CCD imaging detectors in the self-reference wavefront sensor of Mach-Zehnder interferometric method is complementary, the wavefront information that obtains do that front wave solutions is twined and conjugation after just directly in the controlled deformation mirror with the corresponding driver element of CCD pixel.

Two of technical solution of the present invention is: based on the ADAPTIVE OPTICS SYSTEMS of self-reference wavefront sensor and continuous surface deformable mirror, it is characterized in that: by continuous surface deformable mirror, self-reference wavefront sensor and industrial computer based on the Mach-Zehnder interferometric method are formed, wherein the self-reference wavefront sensor based on the Mach-Zehnder interferometric method comprises: first semi-transparent semi-reflecting lens, pinhole filter, completely reflecting mirror, optical attenuator, phase shifter, first imaging detector and second imaging detector, after the aberration corrugated enters system, at first pass through the reflection of continuous surface deformable mirror, enter self-reference wavefront sensor based on the Mach-Zehnder interferometric method, through first semi-transparent semi-reflecting lens corrugated is divided into two bundles, wherein a branch of as wavefront information to be detected source through after the semi-transparent semi-reflecting mirror reflection again through completely reflecting mirror reflection after the optical attenuator decay, to the second semi-transparent semi-reflecting lens place; The light beam that first semi-transparent semi-reflecting lens is crossed in transmission has simultaneously produced reference beam through behind the pinhole filter, this reference beam is again through the last second semi-transparent semi-reflecting lens place that arrives of the reflection of phase shifter, the two-beam ripple forms interference fringe at the second semi-transparent semi-reflecting lens place, image in respectively on first imaging detector and second imaging detector, this moment, phase shifter did not produce phase differential, first imaging detector and second imaging detector will collect two width of cloth interference images simultaneously and output in the industrial computer, make phase shifter produce the phase differential of a pi/2 afterwards, two width of cloth interference images with first imaging detector and the second imaging detector collection export in the industrial computer again, after two step phase shifts, obtain 4 amplitude shift interference figure, in industrial computer, do to obtain wavefront information after the matrix operation, to output in the continuous surface deformable mirror after its conjugation, carry out the closed loop wavefront correction.

The present invention compared with prior art has following advantage:

(1) the present invention adopts the self-reference wavefront sensor based on the Mach-Zehnder interferometric method, has promoted precision and spatial resolution that the corrugated is surveyed.

(2) compare with traditional Hartmann wave front sensor, the self-reference wavefront sensor cost is lower, and can be with wavefront information as independently point source output, and subsequent treatment is comparatively convenient, and when using with distorting lens number of unit coupling, control algolithm is more or less freely.

(3) continuous surface deformable mirror of the present invention has adopted material such as PZT, PMN, compare with the liquid crystal spatial modulator, has response speed faster, capacity usage ratio is higher, characteristics such as chromatic dispersion is little, can improve this wavefront correction performance greatly, enlarge the application of this ADAPTIVE OPTICS SYSTEMS, and can when atmospheric exploration, use based on the ADAPTIVE OPTICS SYSTEMS of interfering wave front detector.

(4) light beam is earlier by behind the wave-front corrector, reflection enters the self-reference wavefront sensor based on the Mach-Zehnder interferometric method, output controlled quentity controlled variable control wave-front corrector carried out closed loop after the wavefront information that detects was made a front wave solutions winding and conjugation through industrial computer to wavefront information, can improve this wavefront correction performance based on the ADAPTIVE OPTICS SYSTEMS of interfering wave front detector greatly.

Description of drawings

Fig. 1 is the principle schematic based on the self-reference wavefront sensor of Mach-Zehnder interferometric method.

Embodiment

As shown in Figure 1, after the aberration corrugated enters system, at first pass through the reflection of continuous surface deformable mirror 10, enter self-reference wavefront sensor based on the Mach-Zehnder interferometric method, through first semi-transparent semi-reflecting lens 1 corrugated is divided into two bundles, wherein a branch of as wavefront information to be detected source through after semi-transparent semi-reflecting lens 1 reflection again through completely reflecting mirror 4 reflections after optical attenuator 5 decay, to second semi-transparent semi-reflecting lens, 6 places; The light beam that first semi-transparent semi-reflecting lens 1 is crossed in transmission has simultaneously produced with reference to the corrugated through behind the pinhole filter 2, this reference wavefront is again through last second semi-transparent semi-reflecting lens, 6 places that arrive of the reflection of phase shifter 3, the two-beam ripple images in respectively on first ccd detector 7 and second ccd detector 8 in second semi-transparent semi-reflecting lens, 6 place's interference fringes.In implementation process, first step phase shifter does not produce phase differential, first ccd detector 7 and second ccd detector 8 will collect two width of cloth interference images simultaneously and output in the industrial computer 9, make phase shifter 3 produce the phase differential of a pi/2 afterwards, that first ccd detector 7 and second ccd detector 8 are gathered exporting in the industrial computer 9 again, obtain 4 amplitude shift interference figure in two steps after the phase shifts, establish the incident corrugated and be:

$U_b(x,y)=A_0(x,y)e^{i{\mathrm{\φ}}_b(x,y)}---\left(1\right)$

Wherein, A ₀(x y) is complex amplitude,

Be incident corrugated phase place, in the ideal case, through after the reference path, the corrugated becomes plane wave, and is as follows:

U _r(x，y)＝A _r(x，y)e ^iθ (2)

Wherein, θ is differing of phase shifter generation, and is relevant through behind the interference system when two bundles like this, when light meets once more, will produce interference:

$I_1(x,y)=A_b^2(x,y)+A_r^2(x,y)+2A_b^2(x,y)A_r^2(x,y)\cos ({\mathrm{\φ}}_b(x,y)+\mathrm{\π}-\mathrm{\θ})---\left(3\right)$

$I_2(x,y)=A_b^2(x,y)+A_r^2(x,y)+2A_b^2(x,y)A_r^2(x,y)\cos ({\mathrm{\φ}}_b(x,y)-\mathrm{\θ})---\left(4\right)$

Wherein, I ₁(x y) is the interference light intensity of surveying on first ccd detector 7, I ₂(x y) is the interference light intensity of surveying on second ccd detector 8, and two-way phase of light wave phase difference of pi is to work as owing to reference path in first ccd detector, the 8 detection light paths experiences primary event more $\mathrm{\θ}=0,\frac{\mathrm{\π}}{2}$ The time,

$I_2(x,y;\mathrm{\θ}=0)=A_b^2(x,y)+A_r^2(x,y)+2A_b^2(x,y)A_r^2(x,y)\cos \left({\mathrm{\φ}}_b(x,y)\right)---\left(5\right)$

$I_1(x,y;\mathrm{\θ}=\frac{\mathrm{\π}}{2})=A_b^2(x,y)+A_r^2(x,y)+2A_b^2(x,y)A_r^2(x,y)\cos ({\mathrm{\φ}}_b(x,y)+\frac{\mathrm{\π}}{2})---\left(6\right)$

$I_1(x,y;\mathrm{\θ}=0)=A_b^2(x,y)+A_r^2(x,y)+2A_b^2(x,y)A_r^2(x,y)\cos ({\mathrm{\φ}}_b(x,y)+\mathrm{\π})---\left(7\right)$

$I_2(x,y;\mathrm{\θ}=\frac{\mathrm{\π}}{2})=A_b^2(x,y)+A_r^2(x,y)+2A_b^2(x,y)A_r^2(x,y)\cos ({\mathrm{\φ}}_b(x,y)+\frac{3\mathrm{\π}}{2})---\left(8\right)$

Obtain four step phase shift light intensity, can inverting obtain phase front thus:

${\widehat{\mathrm{\φ}}}_b(x,y)=\arctan \left(\frac{I_2(x,y;\mathrm{\θ}=\frac{\mathrm{\π}}{2})-I_1(x,y;\mathrm{\θ}=\frac{\mathrm{\π}}{2})}{I_2(x,y;\mathrm{\θ}=0)-I_1(x,y;\mathrm{\θ}=0)}\right)---\left(9\right)$

(9) in the formula

Be the wavefront information that is directly obtained by inverse trigonometric function arctan θ, (π π) need separate winding to it, establishes: unwrap () owing to arctan θ ∈; For separating the winding function, then:

Phase unwrapping around, can adopt least square (difference) method, find the solution a Poisson equation that satisfies the Neumann boundary condition, multiple method for solving is arranged, dct transform, FFT fast fourier transform etc.

In industrial computer, at first calculated recovery matrix p ^-1, the corrugated matrix after the detection is input in the industrial computer 9 to multiply each other with recovery matrix separates winding, and the corrugated matrix after the recovery that obtains outputs to continuous surface deformable mirror 10, carries out the closed loop wavefront correction.

Claims (3)

1, ADAPTIVE OPTICS SYSTEMS based on self-reference wavefront sensor and continuous surface deformable mirror, it is characterized in that: by continuous surface deformable mirror, self-reference wavefront sensor and industrial computer based on the Mach-Zehnder interferometric method are formed, wherein the self-reference wavefront sensor based on the Mach-Zehnder interferometric method comprises: first semi-transparent semi-reflecting lens, pinhole filter, completely reflecting mirror, optical attenuator, phase shifter, first imaging detector and second imaging detector, after the aberration corrugated enters system, at first pass through the reflection of continuous surface deformable mirror, enter self-reference wavefront sensor based on the Mach-Zehnder interferometric method, through first semi-transparent semi-reflecting lens corrugated is divided into two bundles, wherein a branch of as wavefront information to be detected source through after the semi-transparent semi-reflecting mirror reflection again through completely reflecting mirror reflection after the optical attenuator decay, to the second semi-transparent semi-reflecting lens place; The light beam that first semi-transparent semi-reflecting lens is crossed in transmission has simultaneously produced reference beam through behind the pinhole filter, this reference beam is again through the last second semi-transparent semi-reflecting lens place that arrives of the reflection of phase shifter, the two-beam ripple forms interference fringe at the second semi-transparent semi-reflecting lens place, image in respectively on first imaging detector and second imaging detector, this moment, phase shifter did not produce phase differential, first imaging detector and second imaging detector will collect two width of cloth interference images simultaneously and output in the industrial computer, make phase shifter produce the phase differential of a pi/2 afterwards, two width of cloth interference images with first imaging detector and the second imaging detector collection export in the industrial computer again, after two step phase shifts, obtain 4 amplitude shift interference figure, in industrial computer, do to obtain wavefront information after the matrix operation, to output in the continuous surface deformable mirror after its conjugation, carry out the closed loop wavefront correction.

2, the ADAPTIVE OPTICS SYSTEMS based on self-reference wavefront sensor and continuous surface deformable mirror according to claim 1 is characterized in that: the unit cell arrangement of described continuous surface deformable mirror and number of unit and arrange based on detected pixel in two imaging detectors in the self-reference wavefront sensor of Mach-Zehnder interferometric method is complementary.

3, the ADAPTIVE OPTICS SYSTEMS based on self-reference wavefront sensor and continuous surface deformable mirror according to claim 1 is characterized in that: described continuous surface deformable mirror adopts PZT or PMN material to make.

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