CN205719274U - Calibration device for frequency response characteristics of shack-Hartmann wavefront sensor - Google Patents

Abstract

The utility model relates to a calibration device for the frequency response characteristic of a shack-Hartmann wavefront sensor, which comprises a knife edge, a knife edge position precise adjustment device, a collimating mirror and a sensor which are arranged on the output light path of a laser in sequence; the optical axis of the sensor and the collimating mirror is penetrated; the row direction of the microlens array of the sensor is perpendicular to the XOZ plane of the spatial rectangular coordinate system, and the column direction is parallel to the OX axis of the spatial rectangular coordinate system. The knife edge is arranged on the knife edge position precision adjusting device, and the distance between the knife edge and the plane where the micro-lens array is located is less than L_x/(λv_max)，v_maxIs the cut-off frequency of the sensor, L_xThe working length of the sensor in the X direction is defined, and lambda is the wavelength of laser output by the laser; the edge of the knife edge is parallel to the row direction of the micro-lens array, the edge is positioned below the micro-lens array, and the edge intersects the center of the row of lenses at the lowest part of the micro-lens array along the extension line of the optical axis direction of the collimating mirror. The utility model discloses can acquire the sensor response characteristic at full frequency channel.

Description

The caliberating device of Shack-Hartmann wavefront sensor Frequency Response

Technical field

This utility model belongs to optical field, relates to a kind of Shack-Hartmann wavefront sensor frequency response The caliberating device of characteristic.

Background technology

Shack-Hartmann wavefront sensor is mainly made up of microlens array and detector, at optical element With optical system wavefront aberration test, light laser parameter diagnosis and control, atmospheric turbulance parameter measurement, human eye The fields such as aberration measurement are widely used.The Shack-Hartmann wavefront sensor temporal coherence to light source Less demanding, there is simple in construction, easily operated, environmental suitability is strong, real-time is good, dynamic range The advantage such as big.

At present, the scaling method of Shack-Hartmann wavefront sensor frequency response characteristic is for making different frequency The phase-plate of rate, irradiates phase-plate with monochromatic collimated beam ripple, Shack-Hartmann wavefront sensor measures The outgoing light wave of phase-plate, thus obtain Shack-Hartmann wavefront sensor response at corresponding frequencies Characteristic.But, current technology level there is no method and ensures the machining accuracy of high-frequency phase plate, and processing is not Costly, phase-plate method cannot obtain Shack-Hartmann wavefront sensor entirely to same frequency phase-plate The response characteristic of frequency range.

Utility model content

According to background above, it is special that this utility model provides a kind of Shack-Hartmann wavefront sensor frequency response The caliberating device of property, this caliberating device can obtain the Shack-Hartmann wavefront sensor response at full frequency band Characteristic.

This utility model, based on diffraction theory, utilizes laser instrument and the edge of a knife to produce the space frequency of light intensity, phase place Rate is all along Shack-Hartmann wavefront sensor column direction continually varying diffracted wave, it is achieved Shack-Hartmann The demarcation of Wavefront sensor frequency response characteristic.

The technical solution of the utility model is:

The caliberating device of Shack-Hartmann wavefront sensor Frequency Response, including laser instrument, collimating mirror and Shack-Hartmann wavefront sensor；Described collimating mirror and Shack-Hartmann wavefront sensor set gradually On the output light path of laser instrument；The optical axis of described Shack-Hartmann wavefront sensor and collimating mirror is put on； Described Shack-Hartmann wavefront sensor includes microlens array；The line direction of described microlens array hangs down Straight in the XOZ plane of rectangular coordinate system in space, column direction is parallel to the OX axle of rectangular coordinate system in space； It is characterized in that caliberating device also includes the edge of a knife and knife-edge positions device for precisely regulating；The described edge of a knife It is arranged on knife-edge positions device for precisely regulating, and is positioned at collimating mirror and Shack-Hartmann wavefront sensor Between light path on；Timing signal, the edge of a knife distance away from microlens array place plane is less than L_x/(λv_max), v_maxFor the cut-off frequency of Shack-Hartmann wavefront sensor, L_xFor Shack-Hartmann wavefront sensor Active length in the X direction, λ is the wavelength of described laser instrument Output of laser；The sword limit of the edge of a knife and institute The line direction stating microlens array is parallel, and there are certain distance, position, sword limit in the entrance pupil edge of sword back gauge collimating mirror Below microlens array, the extended line of sword edge collimating mirror optical axis direction meets at microlens array bottom The center of a line lens；Outgoing collimated light beam after the collimated mirror of monochromatic light that described laser instrument sends, institute Stating collimated light beam after the sword limit diffraction of the edge of a knife, the dead ahead at microlens array produces for Shack-Kazakhstan The diffraction light wave phase distribution that special graceful Wavefront sensor Frequency Response is demarcated, and the phase place of this diffraction light wave Spatial frequency is linearly increasing on Shack-Hartmann wavefront sensor column direction.

Above-mentioned knife-edge positions device for precisely regulating is made up of automatically controlled turntable and D translation platform, and the edge of a knife is arranged on On automatically controlled turntable, export wave front data in real time in conjunction with Shack-Hartmann wavefront sensor, it is achieved edge of a knife position That puts is automatically adjusted.

This utility model has the advantages that

1, this utility model is based on diffraction theory, utilizes the parallel one-wavelength laser of collimating mirror outgoing, through the edge of a knife Diffraction and generate light intensity, phase place spatial frequency all along Shack-Hartmann wavefront sensor microlens array Continually varying diffraction light wave on column direction, by wavefront measured by contrast Shack-Hartmann wavefront sensor Data and gross data, thus can disposably realize Shack-Hartmann wavefront sensor full frequency band frequency The demarcation of response characteristic, the performance for Wavefront sensor provides comprehensive decision criteria.

2, this utility model utilizes knife-edge positions device for precisely regulating to achieve sword edge direction and the Shack of the edge of a knife The high accuracy alignment of the line direction of the microlens array of-Hartmann wave front sensor, thus improve frequency The reliability of Response Features Scaling.

3, this utility model calculating response time is short, and result of calculation accuracy is high.

4, this utility model simple in construction, stability are high, reproducible, and measurement result confidence level is high.

Accompanying drawing explanation

Fig. 1 is structural representation of the present utility model；

Fig. 2 is the structural representation of knife-edge positions device for precisely regulating of the present utility model；

In figure, 1-laser instrument, 2-collimating mirror, 3-knife-edge positions device for precisely regulating, the automatically controlled turntable of 31-, 32- D translation platform, 4-Shack-Hartmann wavefront sensor, 5-microlens array, 6-diffraction light wave phase divides Cloth, the 7-edge of a knife.

Detailed description of the invention

With detailed description of the invention, this utility model is elaborated below in conjunction with the accompanying drawings.

Fig. 1 show the mark of Shack-Hartmann wavefront sensor Frequency Response provided by the utility model Determining the structural representation of device, it includes laser instrument 1, collimating mirror 2, Shack-Hartmann wavefront sensor 4, knife-edge positions device for precisely regulating 3, the edge of a knife 7；Wherein, collimating mirror 2 and Shack-Hartmann wavefront Sensor 4 is successively set on the output light path of laser instrument 1.

Shack-Hartmann wavefront sensor 4 includes microlens array 5, and the line direction of microlens array is vertical In the XOZ plane of rectangular coordinate system in space, column direction is parallel to the OX axle of rectangular coordinate system in space；Summer Gram-Hartmann wave front sensor 4 puts on (i.e. each micro-in microlens array 5 with the optical axis of collimating mirror 2 The optical axis of lens is all parallel with the optical axis of collimating mirror 2).

Knife-edge positions device for precisely regulating 3 is made up of automatically controlled turntable 31 and D translation platform 32；The edge of a knife 7 It is arranged on automatically controlled turntable 31, and between collimating mirror 2 and Shack-Hartmann wavefront sensor 4 In light path.Timing signal, utilizes D translation platform 32 that the edge of a knife 7 is cut light path, by adjusting knife-edge positions Device for precisely regulating 3 makes the sword limit of the edge of a knife 7 parallel with the line direction of microlens array 5, and sword back gauge collimates There is certain distance (being preferably maintained at least more than 5mm) at the entrance pupil edge of mirror 2, and sword limit is positioned at lenticule battle array Below row 5, it is saturating that the extended line of sword edge collimating mirror 2 optical axis direction meets at microlens array 5 bottom row The center of mirror；The edge of a knife 7 distance away from microlens array 5 place plane is slightly less than L_x/(λv_max), v_max For the cut-off frequency of Shack-Hartmann wavefront sensor 4, L_xFor Shack-Hartmann wavefront sensor 4 Active length in the X direction.Now, the sword limit diffraction light wave phase of the edge of a knife 7 will be completely covered Shack The significant response frequency range of-Hartmann wave front sensor 4.

Calibration principle of the present utility model is:

According to diffraction theory, monochromatic collimated beam ripple is after the sword limit diffraction of the edge of a knife 7, in its rear at distance z Diffraction light wave there is following light intensity, PHASE DISTRIBUTION form:

$I=1-\frac{\sqrt{2}}{\mathrm{\π}\mathrm{\ϵ}}cos(\frac{{\mathrm{\π\ϵ}}^2}{2}+\frac{\mathrm{\π}}{4})---\left(1\right)$

$\mathrm{\φ}=-\frac{\sqrt{2}}{2\mathrm{\π}\mathrm{\ϵ}}sin(\frac{{\mathrm{\π\ϵ}}^2}{2}+\frac{\mathrm{\π}}{4})---\left(2\right)$

In formulaWherein λ is the wavelength of monochromatic collimated beam ripple, and x represents along X-direction The lenticule distance away from edge of a knife sword limit, z represent along Z-direction microlens array place plane from sword limit away from From.

The light intensity of sword limit diffraction light wave and the change frequency of PHASE DISTRIBUTION of the edge of a knife 7 be:

V=x/ (λ z) (3)

Formula (3) shows that the change frequency that Diffraction Diffraction phase of light wave is distributed is linearly increasing along X-direction, Containing abundant frequency content in the wavefront signals of Diffraction Diffraction phase of light wave distribution, based on this to Shack- The Frequency Response of Hartmann wave front sensor 4 is demarcated.

Outgoing collimated light beam after the collimated mirror of monochromatic light 2 that laser instrument 1 sends, this collimated light beam is through the edge of a knife 7 Sword limit diffraction after, at the dead ahead of microlens array 5, generation is used for Shack-Hartmann wavefront sensing The diffraction light wave phase distribution 6 that device 4 Frequency Response is demarcated.Shack-Hartmann wavefront sensor 4 is utilized to obtain Take the wave front data of diffraction light wave phase distribution 6, and this wave front data is carried out Fourier transformation；Simultaneously The wave front data of theoretical derivation gained diffraction light wave phase distribution is carried out Fourier transformation, by Fu of the two In leaf transformation result be divided by the response i.e. obtaining Shack-Hartmann wavefront sensor 4 to different frequency wavefront Characteristic.

Utilize the method tool that Shack-Hartmann wavefront sensor Frequency Response is demarcated by this utility model Body is as follows: [note: the sequencing of step (2) and step (3) can exchange]

(1) open laser instrument 1, adjust the position of Shack-Hartmann wavefront sensor 4 so that it is with set The collimating mirror 2 put on laser instrument 1 output light path is put on.

(2), at the dotted line position being placed in Fig. 1 by knife-edge positions device for precisely regulating 3, edge of a knife position is controlled Put the automatically controlled turntable 31 of device for precisely regulating 3, make sword edge direction and the Shack of the edge of a knife 7 mounted thereto The line direction of the microlens array 5 of-Hartmann wave front sensor 4 is parallel.

(3) by D translation platform 32, the edge of a knife 7 is cut in light path, makes the edge of a knife 7 sword limit be positioned at micro- Below lens array 5, and the extended line of the edge of a knife 7 sword edge collimating mirror 2 optical axis direction is made to meet at lenticule battle array The center of row 5 bottom row lens, makes the edge of a knife 7 distance away from microlens array 5 place plane smaller In L_x/(λv_max), v_maxFor the cut-off frequency of Shack-Hartmann wavefront sensor, L_xFor Shack-Hart Graceful Wavefront sensor active length in the X direction.

(4), after being adjusted by device by above-mentioned steps, generation is used for by the dead ahead at microlens array 5 The diffraction light wave phase distribution 6 demarcated；Shack-Hartmann wavefront sensor 4 is utilized to obtain diffraction light wave phase The wave front data of position distribution 6, carries out Fourier transformation to measured wave front data, pushes away theory simultaneously The wave front data of the diffraction phase distribution leading gained carries out Fourier transformation, the Fourier transformation of the two is tied Fruit is divided by the response characteristic i.e. obtaining Shack-Hartmann wavefront sensor to different frequency wavefront, i.e.

$F=\frac{FFT\left(W_{test}\right)}{FFT\left(W_{theory}\right)}---\left(4\right)$

In formula: FFT represents Fourier transformation；W_testActual ripple measured by Shack-Hartmann wavefront sensor Front data；W_theoryFor theoretical wavefront data.

By aforementioned formula (3) it can be seen that when sword edge direction is parallel to the line direction of microlens array 5, Wave front data measured by Shack-Hartmann wavefront sensor 5 is consistent at the line direction of microlens array 5, Therefore, above-mentioned steps (2) can be passed through formula (5) and pass judgment on sword edge direction and the ripple of the edge of a knife 7 The parallel degree in front sensor detector row direction, computing formula is as follows:

$\mathrm{\Δ}=\frac{1}{M}\underset{i=1}{\overset{M}{\Σ}}\underset{j=1}{\overset{N}{\Σ}}\sqrt{\frac{{(w_{i,j}-\stackrel{\‾}{w_i})}^2}{N-1}}---\left(5\right)$

In formula, w_i,jThe i-th row jth row wave front data acquired in described Shack-Hartmann wavefront sensor, The meansigma methods of the i-th row wave front data acquired in described Shack-Hartmann wavefront sensor,

Claims (2)

1. the caliberating device of Shack-Hartmann wavefront sensor Frequency Response, including laser instrument, collimating mirror And Shack-Hartmann wavefront sensor；Described collimating mirror and Shack-Hartmann wavefront sensor set successively Put on the output light path of laser instrument；The optical axis of described Shack-Hartmann wavefront sensor and collimating mirror is worn Good；Described Shack-Hartmann wavefront sensor includes microlens array；The row side of described microlens array To being perpendicular to the XOZ plane of rectangular coordinate system in space, column direction is parallel to the OX of rectangular coordinate system in space Axle；It is characterized in that: caliberating device also includes the edge of a knife and knife-edge positions device for precisely regulating；

The described edge of a knife is arranged on knife-edge positions device for precisely regulating, and is positioned at collimating mirror and Shack-Hart In light path between graceful Wavefront sensor；Timing signal, the described edge of a knife away from microlens array place plane away from From less than L_x/(λv_max), v_maxFor the cut-off frequency of Shack-Hartmann wavefront sensor, L_xFor Shack- Hartmann wave front sensor active length in the X direction, λ is the wavelength of described laser instrument Output of laser； The sword limit of the edge of a knife is parallel with the line direction of described microlens array, and the entrance pupil edge of sword back gauge collimating mirror has one Set a distance, sword limit is positioned at below microlens array, and the extended line of sword edge collimating mirror optical axis direction meets at micro- The center of lens arra bottom a line lens；

Outgoing collimated light beam after the collimated mirror of monochromatic light that described laser instrument sends, described collimated light beam is through cutter After the sword limit diffraction of mouth, the dead ahead at microlens array produces for Shack-Hartmann wavefront sensor The diffraction light wave phase distribution that Frequency Response is demarcated, and the spatial frequency of the phase place of this diffraction light wave is at Shack On-Hartmann wave front sensor column direction linearly increasing.

The caliberating device of Shack-Hartmann wavefront sensor Frequency Response the most according to claim 1, It is characterized in that: described knife-edge positions device for precisely regulating is made up of automatically controlled turntable and D translation platform, cutter Mouth is arranged on automatically controlled turntable.