JP2008241896A - Phase distribution controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a phase distribution controller capable of computing a phase distribution of a light wave with high accuracy with a low-cost and simple constitution and controlling the phase distribution of the light wave at a high speed. <P>SOLUTION: The phase distribution controller includes a condenser lens 4 which converges a light wave phase-modulated by an SLM 3; a third splitter 5 which divides the converged light wave into a reflected light wave and a transmitted light wave; plane mirrors 6 and 7 which bend the transmitted light wave, a CCD camera 20 which receives the reflected wave and the bent transmitted light wave and outputs an intensity distribution as an image signal; a signal processor 21 which outputs a phase distribution signal of the light wave phase-modulated by the SLM 3; and an SLM controller 22, which outputs a control signal to the SLM 3 so that the phase distribution of the light wave phase-modulated by the SLM 3 is a predetermined phase distribution; the third splitter 3 and planar mirrors 6 and 7, disposed so that the reflected light wave and the transmitted light wave bent by the planar mirrors 6 and 7 become substantially parallel to each other and are incident on portions that are different in a photodetection surface 11. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a phase distribution control device that controls spatial light modulation means in which reflecting mirrors such as micromirrors are arranged in an array to control the phase distribution of light waves.

For example, in a large astronomical telescope, there is a limit to the size of a mirror that can be produced with one piece. Therefore, a split primary mirror that constitutes a large-diameter primary mirror by arranging a plurality of mirrors (hereinafter referred to as “segment mirrors”) (spatial light modulation means) has been put into practical use.
In an astronomical telescope using a split primary mirror, it is necessary to control the angle and position of each segment mirror with high accuracy so that the wave front of the reflected wave reflected by the split primary mirror has a desired phase distribution. The allowable error is a fraction of the wavelength.
In order to control the angle and position of the segment mirror, a general phase distribution control device includes a signal processing device (signal processing means) that calculates the phase distribution (wavefront) of the reflected wave reflected by the split primary mirror, and this A spatial light modulation control device (spatial light modulation control means) that calculates a control command value for the segment mirror is provided so that the phase distribution becomes a desired phase distribution.

Here, as a method for calculating the phase distribution of the light wave, a phase diversity method is conventionally known.
In the phase diversity method, a light wave collected by a condensing optical system (condensing means) is imaged by an imaging camera (imaging means), its intensity distribution is measured, and an iterative operation such as a phase recovery method is performed on the intensity distribution. Is executed to calculate the phase distribution of the light wave before focusing. This method is characterized in that the optical system is easily configured as compared with other methods using an interferometer or the like.

In the phase diversity method, an image at the focal position of the condensing optical system (hereinafter referred to as an “in-focus image”) and an image on a surface shifted from the focal position (hereinafter referred to as an “out-focus image”) due to a calculation algorithm request. It is necessary to take a picture.
Here, in the case of static control, an in-focus image and an out-focus image can be captured by changing the distance between the condensing optical system and the imaging unit and performing imaging twice or more.
However, in the case of dynamic control, the time required to capture a plurality of images in time series and the time for mechanical drive cannot be widened, and control can be speeded up. There was a problem that it was not possible.

  As a method for solving this problem, a beam splitter (branching means) is arranged behind the condensing optical system to split the condensed light wave into two, and the branched light waves are used as an in-focus image and an out-focus image, respectively. A method of simultaneously capturing images with two image capturing cameras has been proposed (see, for example, Non-Patent Document 1).

As another method, one imaging camera is provided by arranging the beam splitter so that the light wave transmitted through the beam splitter (branching means, bending means) and the light wave reflected twice in the beam splitter are parallel to each other. In addition, a method for capturing an in-focus image and an out-focus image in one frame has been proposed (see, for example, Non-Patent Document 2).
According to these methods, since the phase distribution is calculated at the frame rate of the imaging camera, the phase distribution is controlled at a high control speed in synchronization with the frame rate of the imaging camera.

David J.M. Lee, Michael C.L. Roggemann, Byron M .; Welsh, and Erin R. Crosby, “Evaluation of least-squares phase-diversity technology for space telescopic wave-front sensing”, APPLIED OPTICS, Vol. 36, no. 35, 10 December 1997, p. 9186-9197 Mats G. Lofdahl, Thomas E .; Berger, Richard S .; Shine, and Alan M. et al. Title, “PREPARATION OF A DUAL WAVELENGTH SEQUENCE OF HIGH-RESOLUTION SOLAR PHOTOOSPHERIC IMAGES USING PHASE DIVERSITY”, THE ASTROPHYSICAL JOURNAL. 495, 10 March 1998, p. 965-972

In the conventional phase distribution control device described in Non-Patent Document 1, an image for inputting an image signal output from the imaging camera (including the intensity distribution of the captured in-focus image or out-focus image) to the signal processing device. As many input devices as the number of imaging cameras are required. In addition, it is necessary to drive a plurality of imaging cameras synchronously.
Therefore, there are problems that the configuration of the apparatus is complicated and the cost is increased.

In the conventional phase distribution control device described in Non-Patent Document 2, the amount of defocus for obtaining an out-of-focus image (hereinafter referred to as “focus shift amount”) is determined by the dimensions of the beam splitter. .
However, when the back focus of the condensing optical system is short, the size of the beam splitter is limited and the amount of focus deviation cannot be increased sufficiently.
Therefore, there is a problem that the calculation accuracy of the phase distribution is lowered.

  An object of the present invention is to solve the above-described problems, and an object of the present invention is to calculate the phase distribution of the light wave with high accuracy with a low-cost and simple configuration. An object of the present invention is to provide a phase distribution control device capable of controlling at a high speed.

  The phase distribution control device according to the present invention includes a spatial light modulation unit that modulates the phase of a light wave, a condensing unit that collects a light wave phase-modulated by the spatial light modulation unit, and a light wave collected by the condensing unit. Branching means for splitting the reflected light wave by reflection and transmitted light wave by transmission, bending means for reflecting and bending the transmitted light wave, reflected light wave and transmitted light wave bent by the bending means are received by the light receiving surface An imaging unit that measures the intensity distribution and outputs the intensity distribution as an image signal, and a signal processing unit that calculates the phase distribution of the light wave phase-modulated by the spatial light modulation unit based on the image signal and outputs the phase distribution signal And a spatial light modulation control that outputs a control signal for controlling the spatial light modulation means so that the phase distribution of the light wave phase-modulated by the spatial light modulation means becomes a predetermined phase distribution based on the phase distribution signal Means Branching means and the bending means includes a transparent light wave which is bent by the reflection light wave and the bending means, substantially becomes parallel to each other and in which are arranged to be incident to different parts of each light receiving surface.

According to the phase distribution control device of the present invention, the branching unit and the bending unit are configured such that the reflected light wave and the transmitted light wave bent by the bending unit are substantially parallel to each other and are incident on different portions of the light receiving surface. Is arranged.
Therefore, it is possible to calculate the phase distribution of the light wave with high accuracy and to control the phase distribution of the light wave at a high speed with an inexpensive and simple configuration.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding members and parts will be described with the same reference numerals.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing a phase distribution control apparatus 100 according to Embodiment 1 of the present invention. FIG. 1 shows a configuration in which the spatial phase distribution of a laser beam (light wave) incident from the outside is modulated by an SLM 3 (described later).

  In FIG. 1, a phase distribution control apparatus 100 includes a cube-type beam splitter 1 (hereinafter abbreviated as “first splitter 1”) and a cube-type beam splitter 2 (hereinafter abbreviated as “second splitter 2”). ), A segment mirror type spatial light modulator 3 (spatial light modulation means, hereinafter referred to as “SLM (Spatial Light Modulator) 3”), a condensing lens 4 (condensing means), and a plate-type beam splitter 5 (branching means, hereinafter referred to as “third splitter 5”), two plane mirrors 6 and 7 (bending means, plane mirror), CCD camera 20 (imaging means), and signal processing device 21 (signal processing) Means) and an SLM control device 22 (spatial light modulation control means).

  The phase distribution control apparatus 100 according to the present embodiment calculates the spatial phase distribution of the laser beam phase-modulated by the SLM 3, and feeds back the phase modulation amount by the SLM 3 so that the spatial phase distribution becomes a predetermined spatial phase distribution. I have control. Therefore, a laser beam that is phase-modulated by the SLM 3 and reflected by the second splitter 2 is used.

The first splitter 1 reflects and transmits a laser beam incident from the outside and a laser beam reflected by the SLM 3. The second splitter 2 reflects and transmits the laser beam reflected by the first splitter 1 and the laser beam reflected by the SLM 3.
The SLM 3 modulates and reflects the phase of the laser beam reflected by the first splitter 1 and transmitted through the second splitter 2.

The condensing lens 4 condenses the laser beam that is phase-modulated by the SLM 3 and reflected by the second splitter 2.
The third splitter 5 divides the amplitude of the laser beam condensed by the condenser lens 4 into a reflected light wave by reflection and a transmitted light wave by transmission. The plane mirrors 6 and 7 respectively reflect and bend the transmitted light wave that has passed through the third splitter 5.

The reflected light wave reflected by the third splitter 5 converges to become the first convergent light 8, passes through the third splitter 5, bends by the plane mirrors 6, 7, and passes through the third splitter 5 again. The light wave converges to become the second converged light 9.
Here, since the first convergent light 8 and the second convergent light 9 propagate through different paths, an arbitrary optical path length difference may be provided between the first convergent light 8 and the second convergent light 9. it can.

The CCD camera 20 receives the first convergent light 8 and the second convergent light 9 by the light receiving surface 11 provided at the focal position of the first convergent light 8 and captures them as an in-focus image and an out-focus image, respectively. .
At this time, since there is a difference in optical path length between the first convergent light 8 and the second convergent light 9, the first convergent light 8 and the second convergent light 9 have different amounts of defocus.
Further, the CCD camera 20 photoelectrically converts the captured in-focus image and out-focus image and outputs them as an image signal indicating the spatial intensity distribution of the laser beam.

Based on the image signal output from the CCD camera 20, the signal processing device 21 executes repetitive calculations such as a phase recovery method for the spatial intensity distribution of the laser beam as shown in Non-Patent Documents 1 and 2, for example. The spatial phase distribution of the laser beam phase-modulated by the SLM 3 is calculated and a phase distribution signal is output.
The signal processing device 21 includes an image input device for inputting an image signal output from the CCD camera 20.

  The SLM controller 22 is configured so that the spatial phase distribution of the laser beam phase-modulated by the SLM 3 based on the phase distribution signal input from the signal processing device 21 becomes a predetermined spatial phase distribution set in advance. And a control signal for controlling the SLM 3 is output.

Here, the CCD camera 20, the signal processing device 21, and the SLM control device 22 each include a microprocessor (not shown) having a CPU and a memory storing a program.
The predetermined spatial phase distribution of the laser beam is stored in advance in the memory of the SLM control device 22.
The third splitter 5 and the plane mirrors 6 and 7 are arranged so that the first convergent light 8 and the second convergent light 9 are substantially parallel to each other and are incident on different portions of the light receiving surface 11 respectively. Yes.

Hereinafter, the operation of the phase distribution control device 100 configured as described above will be described.
First, a laser beam incident on the first splitter 1 from the outside (left side in FIG. 1) is reflected by the first splitter 1. The laser beam reflected by the first splitter 1 passes through the second splitter 2.
Subsequently, the laser beam transmitted through the second splitter 2 is phase-modulated by the SLM 3 and reflected.

Next, a part of the laser beam reflected by the SLM 3 passes through the second splitter 2 and the first splitter 1 and is emitted to the outside (upward in FIG. 1).
The remainder of the laser beam reflected by the SLM 3 is reflected by the second splitter 2.
Subsequently, the laser beam reflected by the second splitter 2 is condensed by the condenser lens 4.
The laser beam condensed by the condenser lens 4 is amplitude-divided into a reflected light wave and a transmitted light wave by the third splitter 5.

Next, the transmitted light wave transmitted through the third splitter 5 is reflected and bent by the plane mirrors 6 and 7, respectively. Further, the transmitted light wave bent by the plane mirrors 6 and 7 passes through the third splitter 5 again.
The reflected light wave reflected by the third splitter 5 converges to become the first convergent light 8, and the transmitted light wave that has passed through the third splitter 5 again converges to become the second converged light 9.
The first convergent light 8 and the second convergent light 9 are respectively incident on the CCD camera 20.

  Subsequently, the first converged light 8 and the second converged light 9 incident on the CCD camera 20 are captured as an in-focus image and an out-focus image, respectively, are photoelectrically converted, and image signals indicating the spatial intensity distribution of the laser beam. Is output as

  Next, in the signal processing device 21, the spatial phase distribution of the laser beam phase-modulated by the SLM 3 is calculated based on the image signal from the CCD camera 20 by, for example, repetitive calculation such as a phase recovery method for the spatial intensity distribution of the laser beam. It is calculated and a phase distribution signal is output.

  Subsequently, in the SLM control device 22, based on the phase distribution signal from the signal processing device 21, the spatial phase distribution of the laser beam phase-modulated by the SLM 3 becomes a predetermined spatial phase distribution stored in the memory. The phase modulation amount of the SLM 3 is calculated and a control signal is output.

FIG. 2 is a block diagram showing in detail the third splitter 5 and the plane mirrors 6 and 7 in FIG. 1 and shows the optical path length difference Ld between the first convergent light 8 and the second convergent light 9.
In FIG. 2, for the sake of simplicity, the light beam of the laser beam is represented by a principal ray and represented by an arrow.

  In FIG. 2, the third splitter 5 is arranged so that the incident angle of the laser beam condensed by the condenser lens 4 is 45 °. The plane mirror 6 is arranged so that the incident angle of the transmitted light wave that has passed through the third splitter 5 is 45 °. The plane mirror 7 is arranged so that the incident angle of the transmitted light wave reflected by the plane mirror 6 is 45 °.

Further, the first convergent light 8 and the second convergent light 9 are incident on the light receiving surface 11 with principal rays having a gap Gap.
At this time, since the CCD camera 20 images the first convergent light 8 and the second convergent light 9 with one light receiving surface 11, the gap Gap needs to be set narrower than the width of the light receiving surface 11.
The optical path length of the transmitted light wave passing through the third splitter 5 in the third splitter 5 is L ₁ , the optical path length from the transmitted light wave passing through the third splitter 5 to being reflected by the plane mirror 6 is L ₂ , and transmitted When the optical path length to the light wave is reflected by the plane mirror 7 is reflected by the plane mirror 6 and L _3, the distance gap,, is expressed by the following equation (1).

In the equation (1), the optical path length L ₁ and the refraction angle θ ₂ are expressed by the following equations (2) and (3), respectively, where n is the refractive index of the third splitter 5 and t is the thickness. .

  Further, the following equation (4) is obtained by modifying the equation (1).

Here, from the equation (4), the gap Gap, the optical path length L _1, and the optical path length L ₂ can be set to arbitrary values, respectively, and the optical path length L ₃ is a change in the optical path length L ₁ . It can be seen that it changes with a positive derivative.
Further, the optical path length difference Ld between the first convergent light 8 and the second convergent light 9 is expressed by the following equation (5).

  From Expressions (4) and (5), by operating each parameter, the optical path length difference Ld between the first convergent light 8 and the second convergent light 9 is increased with the gap Gap kept constant. It can be seen that it can be long.

According to the phase distribution control apparatus 100 according to the first embodiment of the present invention, the single convergent light 8 and the second convergent light 9 having different focus deviation amounts are captured by one CCD camera 20 in one frame. Therefore, compared with a method of capturing a plurality of images in time division (time series), a wide feedback control band can be taken, and control can be speeded up.
In addition, since the first converged light 8 and the second convergent light 9 can be imaged by one CCD camera 20, it is possible to realize cost reduction compared to a method using a plurality of image capture cameras. it can.

In addition, since the distance between the third splitter 5 and the plane mirrors 6 and 7 is set to an appropriate value, the amount of defocus between the first convergent light 8 and the second convergent light 9 can be increased without an upper limit. The degree of design freedom can be improved. Further, through experiments, the distance between the third splitter 5 and the plane mirrors 6 and 7 can be easily adjusted to an optimum value.
Moreover, since the 3rd splitter 5 and the plane mirrors 6 and 7 can be comprised using a commercially available cheap beam splitter and plane mirror, cost reduction is realizable.

Embodiment 2. FIG.
FIG. 3 is a block diagram showing a phase distribution control device 100A according to Embodiment 2 of the present invention.
The description of the same configuration as that of the first embodiment will be omitted.
3, the phase distribution control device 100A includes a prism body 10 (branching means, bending means) instead of the third splitter 5 and the plane mirrors 6 and 7 shown in FIG.

4 is a configuration diagram illustrating the prism body 10 of FIG. 3 in detail, FIG. 4 (a) is a perspective view of the prism body 10, and FIG. 4 (b) is a plan view of the prism body 10. FIG.
In FIG. 4, the prism body 10 is integrally formed by bonding a trapezoidal prism 31 (polygonal prism) and a right-angle prism 32 with an adhesive, and constitutes a pentaprism as a whole. The trapezoidal prism 31 and the right-angle prism 32 are bonded to each other on the bonding surface S2.
Further, the bonding surface S2 functions as a beam splitter that divides the amplitude of the laser beam collected by the condenser lens 4 into a reflected light wave by reflection and a transmitted light wave by transmission.

Hereinafter, the operation of the phase distribution control device 100A having the above configuration will be described.
In FIG. 4, the state in which the laser beam incident from the condenser lens 4 is branched in the prism body 10 and emitted in parallel with a gap Gap is represented only by the principal ray, and is represented by an arrow.
First, the laser beam condensed by the condenser lens 4 is incident from one surface S1 sandwiching a right angle in the right-angle prism 32.
Subsequently, the laser beam incident from the surface S1 is amplitude-divided into a reflected light wave and a transmitted light wave at the bonding surface S2.

Next, the reflected light wave reflected by the bonding surface S <b> 2 passes through the other surface S <b> 5 sandwiching the right angle in the right-angle prism 32 and converges to become the first convergent light 8.
Subsequently, the transmitted light wave transmitted through the bonding surface S2 is reflected and bent by the two surfaces S3 and S4 excluding the bonding surface S2 in the trapezoidal prism 31.
Further, the transmitted light wave reflected by the surfaces S3 and S4 is transmitted again through the bonding surface S2, then transmitted through the surface S5, and converges to become the second converged light 9.

Other operations are the same as those in the first embodiment, and the description thereof is omitted.
Also in this case, as described in the first embodiment, the optical path length difference Ld between the first convergent light 8 and the second convergent light 9 and the gap Gap are independently set to arbitrary values. can do.

According to the phase distribution control device 100A according to the second embodiment of the present invention, the single convergent light 8 and the second convergent light 9 having different focus deviation amounts are captured by one CCD camera 20 in one frame. Therefore, compared with a method of capturing a plurality of images in time division (time series), a wide feedback control band can be taken, and control can be speeded up.
In addition, since the first converged light 8 and the second convergent light 9 can be imaged by one CCD camera 20, it is possible to realize cost reduction compared to a method using a plurality of image capture cameras. it can.

  In addition, by using the prism body 10, it is possible to reduce the misalignment of the optical system over time, so that stable measurement can be realized.

In addition, although the trapezoidal prism 31 is used as the polygonal prism in the prism body 10 of the second embodiment, the invention is not limited to this.
The polygonal prism may be a pentaprism 33 as shown in FIG.
Also in this case, the same effects as those of the second embodiment can be obtained.

Embodiment 3 FIG.
Although not mentioned in Embodiments 1 and 2, the longer the focal length of the condenser lens 4 is, the larger the size of the far-field image is and the imaging spatial resolution is improved. Therefore, by increasing the focal length of the condenser lens 4, it is possible to improve the detection spatial resolution of the spatial phase distribution and improve the calculation accuracy of the spatial phase distribution.

However, when the condensing lens 4 is composed of a one-group lens, there is a problem in that the longer the focal length, the longer the total length of the optical system and the larger the apparatus size.
Therefore, it is considered to realize a long focal length with a short optical system by using a plurality of lenses in combination.

FIG. 6 is a block diagram showing a phase distribution control apparatus 100B according to Embodiment 3 of the present invention.
The description of the same configuration as that of the first embodiment will be omitted.
In FIG. 6, the phase distribution control device 100 </ b> B replaces the condensing lens 4 shown in FIG. 1 with a convex lens 4 a (condensing means, positive lens), a plane mirror 4 b, a concave lens 4 c (condensing means, negative lens), And a convex lens 4d (condensing means, positive lens).
Further, the flat mirrors 6 and 7 are respectively fixed by adjusting screws 30 (installation position varying means).

  Here, the plane mirror 4b that bends the laser beam condensed by the convex lens 4a by 90 ° is provided for the convenience of mounting the optical system. Therefore, hereinafter, for the sake of simplicity, a case will be described in which the plane mirror 4b is omitted and the convex lens 4a, the concave lens 4c, and the convex lens 4d are arranged on a straight line.

FIG. 7 is an explanatory diagram showing specific design numerical values when the convex lens 4a, the concave lens 4c, and the convex lens 4d are thin lenses.
In the case of the numerical design example shown in FIG. 7, the combined focal length is 1500 mm, and the distance between the front focal point and the rear focal point is 340 mm.

Here, the front focus and the rear focus are in a Fourier transform relationship. By using this relationship, the spatial intensity distribution of the laser beam at the front focal position can be calculated from the spatial intensity distribution of the laser beam at the rear focal position by a simple signal processing calculation.
Accordingly, at this time, the SLM 3 is disposed at the front focal position.

On the other hand, when the same focal length is constituted by only one group lens, the distance between the front focal point and the rear focal point is 3000 mm.
In other words, by using the third lens group including the convex lens 4a, the concave lens 4c, and the convex lens 4d, the distance between the front focal point and the rear focal point can be greatly shortened as compared with the case where the first lens unit is used.

Further, the adjusting screw 30 is loosened to move the plane mirrors 6 and 7 in parallel while maintaining the angle with respect to the transmitted light wave transmitted through the third splitter 5, so that the plane mirrors 6 and 7 and the third splitter 5 can move in parallel. The interval can be adjusted.
Further, by tightening the adjusting screw 30, the plane mirrors 6 and 7 can be fixed at an arbitrary position.

According to the phase distribution control apparatus 100B according to the third embodiment of the present invention, the single convergent light 8 and the second convergent light 9 having different focus shift amounts are captured by one CCD camera 20 in one frame. Therefore, compared with a method of capturing a plurality of images in time division (time series), a wide feedback control band can be taken, and control can be speeded up.
In addition, since the first converged light 8 and the second convergent light 9 can be imaged by one CCD camera 20, it is possible to realize cost reduction compared to a method using a plurality of image capture cameras. it can.

Further, by setting the distance between the third splitter 5 and the plane mirrors 6 and 7 to an appropriate value using the adjusting screw 30, the amount of defocus between the first convergent light 8 and the second convergent light 9 can be set to an upper limit. Since it can be increased, the degree of freedom in design can be improved. Further, through experiments, the distance between the third splitter 5 and the plane mirrors 6 and 7 can be easily adjusted to an optimum value.
Moreover, since the 3rd splitter 5 and the plane mirrors 6 and 7 can be comprised using a commercially available cheap beam splitter and plane mirror, cost reduction is realizable.

Further, by using a three-group lens including the convex lens 4a, the concave lens 4c, and the convex lens 4d, a long focal length can be realized with a short optical system, so that the apparatus size can be reduced.
Therefore, the stability of the apparatus can be improved and the cost can be reduced.

Further, by arranging the SLM 3 at the front focal length of the third lens group composed of the convex lens 4a, the concave lens 4c and the convex lens 4d, the signal processing calculation can be easily executed.
Therefore, the calculation processing speed can be increased and the control can be further increased.

It is a block diagram which shows the phase distribution control apparatus which concerns on Embodiment 1 of this invention. It is a block diagram which shows the 3rd splitter and flat mirror of FIG. 1 in detail. It is a block diagram which shows the phase distribution control apparatus which concerns on Embodiment 2 of this invention. 4A is a perspective view of the prism body, and FIG. 4B is a plan view of the prism body. It is another block diagram which shows the prism body of FIG. It is a block diagram which shows the phase distribution control apparatus which concerns on Embodiment 3 of this invention. It is explanatory drawing which shows the example of a specific design value at the time of making each the convex lens of FIG. 6, a concave lens, and a convex lens into a thin lens.

Explanation of symbols

  3 SLM (spatial light modulation means), 4 condensing lens (condensing means), 4a, 4d convex lens (condensing means, positive lens), 4c concave lens (condensing means, negative lens), 5 third splitter (branching means) ), 6, 7 plane mirror (bending means, plane mirror), 10 prism body (branching means, bending means), 11 light receiving surface, 20 CCD camera (imaging means), 21 signal processing device (signal processing means), 22 SLM control Device (spatial light modulation control means), 30 adjustment screw (installation position variable means), 31 trapezoidal prism (polygonal prism), 32 rectangular prism, 33 pentaprism (polygonal prism), 100, 100A, 100B phase distribution control device, Gap Spacing, one surface sandwiching a right angle in the S1 right angle prism, S2 bonding surface, S3, S4 bonding surface in the polygonal prism Two other surfaces, S5 The other surface sandwiching a right angle in the right-angle prism.

Claims (5)

Spatial light modulation means for modulating the phase of the light wave;
Condensing means for condensing the light wave phase-modulated by the spatial light modulating means;
Branching means for dividing the light wave collected by the light collecting means into a reflected light wave by reflection and a transmitted light wave by transmission;
Bending means for reflecting and bending the transmitted light wave;
An imaging unit that receives the reflected light wave and a transmitted light wave bent by the bending unit at a light receiving surface to measure an intensity distribution, and outputs the intensity distribution as an image signal;
Based on the image signal, a signal processing unit that calculates a phase distribution of the light wave phase-modulated by the spatial light modulation unit and outputs a phase distribution signal;
Spatial light modulation that outputs a control signal for controlling the spatial light modulation means so that the phase distribution of the light wave phase-modulated by the spatial light modulation means becomes a predetermined phase distribution based on the phase distribution signal Control means,
The branching unit and the bending unit are arranged so that the reflected light wave and the transmitted light wave bent by the bending unit are substantially parallel to each other and are incident on different portions of the light receiving surface, respectively. A characteristic phase distribution control device.   The phase distribution control apparatus according to claim 1, wherein the branching unit includes a plate-type beam splitter, and the bending unit includes two plane mirrors.   3. The phase distribution control device according to claim 2, wherein the bending unit further includes an installation position varying unit that translates the two plane mirrors while maintaining an angle with respect to the transmitted light wave. 4. The branching unit and the bending unit are integrally configured as a prism body in which a right-angle prism and a polygonal prism are bonded to each other,
The prism body is
The light wave condensed by the light condensing means is incident from one surface sandwiching a right angle in the right-angle prism, and then the reflected light wave and the transmitted light wave on the bonding surface of the right-angle prism and the polygonal prism. Is divided into
The reflected light wave is transmitted through the other surface sandwiching a right angle in the right-angle prism;
Further, the transmitted light wave is reflected by two surfaces of the polygonal prism excluding the bonding surface, transmits again through the bonding surface, and then transmits through the other surface. The phase distribution control device according to claim 1.   2. The condensing means is a Fourier transform lens composed of three refractive lenses, and the three refractive lenses are a positive lens, a negative lens, and a positive lens from the incident side. The phase distribution control device according to any one of claims 1 to 4.

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