Concentrating device and optical system for real-time monitoring of laser beam

Abstract

The present invention includes a focusing device comprising micro-diffraction elements configured to diffract incident light applied by a user into G focused beams, wherein each micro-diffraction element belongs to one of the G groups, the micro-diffraction element belonging to the g-th group of the G groups generates the g-th focused beam, the density distribution of the micro-diffraction elements belonging to the g-th group is adjusted to apply an arbitrary intensity distribution to the g-th focused beam before it is focused, the position of the micro-diffraction elements belonging to the g-th group is adjusted to apply an arbitrary wavefront to the g-th focused beam before it is focused, and G is 2 or greater.

Description

Technical Field

[0001] This invention relates to a focusing device for generating multiple focused beams using an incident laser beam and an optical system including the device. More specifically, the invention relates to a focusing device that controls the distribution and position of multiple micro-diffraction elements included in the focusing device to apply arbitrary intensity distribution and arbitrary wavefront to an incident laser beam and generate two or more focused beams; or to an optical system capable of measuring the intensity distribution and wavefront of an incident laser beam using the shape of the focused beams generated by the focusing device. Background Technology

[0002] In optical experiments and industrial applications, it is sometimes necessary to measure the spatial characteristics of a laser beam (i.e., its intensity distribution and wavefront) in real time. The intensity distribution of an incident laser beam can be measured using imaging devices, and the wavefront can be measured using methods such as Shaker-Hartmann sensors or shearing interferometers. However, applying these methods requires additional optical instruments. For example, to measure the intensity distribution and wavefront without interfering with a laser beam being used for other purposes, a beam splitter or similar device is needed to replicate and separate a portion of the laser beam. Furthermore, if the sensor size of the imaging device does not match the size of the laser beam, an optical system such as a telescope must be used to alter the beam size. Additionally, if the intensity of the laser beam being measured is too high, absorptive or reflective filters must be used to appropriately attenuate its intensity. These additional optical instruments increase the complexity of the measurement and introduce unwanted aberrations, thus increasing measurement errors.

[0003] Another method for measuring the wavefront of a laser beam is modal wavefront sensing, in which the incident laser beam is split into multiple beams, additional distinct wavefronts are applied, the beams are focused, and their intensities are compared to measure the wavefront. However, this method also has the drawback of requiring optical instruments such as beam splitters to generate multiple laser beams. Another method using a binary phase mask has also been proposed (US6570143). In this method, diffraction is used to apply different wavefronts and split the beam into multiple focused beams. The intensity distribution and wavefront of the incident laser beam can be measured from the shape changes of the multiple focused beams. However, this method requires additional focusing lenses in addition to the binary phase mask, which introduces the problem of unwanted aberrations being imposed.

[0004] Therefore, there is a need for a method to measure the intensity distribution and wavefront of a laser beam that does not require additional optical instruments such as beam splitters, telescopes, filters or focusing lenses, and does not interfere with the path of the laser beam being used. Summary of the Invention

[0005] Technical issues One problem to be solved by the present invention is to provide a focusing device that uses an incident laser beam to apply arbitrary intensity distribution and arbitrary wavefront to two or more laser beams and to focus the beam; or to provide an optical system that can measure the spatial intensity distribution and wavefront of a laser beam using the shape of the laser beam focused by the focusing device.

[0006] Technical solution One embodiment for addressing the aforementioned problem includes a focusing device comprising micro-diffraction elements configured to diffract incident light applied by a user into G focused beams, wherein each micro-diffraction element belongs to one of the G groups, the micro-diffraction element belonging to the g-th group of the G groups generates the g-th focused beam, the density distribution of the micro-diffraction elements belonging to the g-th group is adjustable to apply an arbitrary intensity distribution to the g-th focused beam before it is focused, the position of the micro-diffraction elements belonging to the g-th group is adjustable to apply an arbitrary wavefront to the g-th focused beam before it is focused, and G is configured to be 2 or greater.

[0007] In one embodiment, the micro-diffraction element includes a microstructure that causes diffraction in the direction of reflection or transmission, the microstructure including a micro-diffraction mirror, a micro-pinhole, etc.

[0008] In one embodiment, G focused beams, focused by the micro-diffraction elements of the focusing device, are focused at different positions on a single focal plane.

[0009] In one embodiment, the coordinates of the nth micro-diffraction element belonging to the g-th group of micro-diffraction elements are arranged... The conditions are determined such that the positions of the micro-diffraction elements do not overlap, and simultaneously the phase error is determined by the following equation. As close to 0 as possible in, It is a light source With the nth micro-diffraction element belonging to group g The distance between them can be calculated using the following equation: It is the nth micro-diffraction element belonging to group g. The focal point of the g-th focused beam The distance between them can be calculated using the following equation: It is the distance between the center point of the light source and the center point of the focusing device, and is calculated using the following equation: It is the center of the focusing device The focal point of the g-th focused beam The distance between them can be calculated using the following equation: m It is a non-negative integer. k It is the wavenumber of the incident light, and is a value obtained by dividing the product of 2π and the refractive index of the space through which the light passes by the center wavelength of the light. It is an arbitrary wavefront function applied to the g-th focused beam before it is focused by the micro-diffraction elements belonging to the g-th group.

[0010] In one embodiment, the size of the micro-diffraction element is determined such that the phase error within the nth micro-diffraction element belonging to the gth group is... The change is less than π.

[0011] In one embodiment, the intensity of the G focused beams can be adjusted by changing the size of the micro-diffraction element.

[0012] In one embodiment, one or more of the G focused beams apply wavefront functions with opposite signs to each other, such that the wavefront information of the incident light can be identified without a separate reconstruction process.

[0013] In one embodiment, the intensity distribution and wavefront of the incident light can be reconstructed using G focused beams or a portion thereof, employing methods such as coherent diffraction imaging reconstruction.

[0014] In one embodiment, in the portion of the focusing device where micro-diffraction elements are absent, some or all of the incident light is absorbed, transmitted, or reflected, thereby enabling the incident light to be used for another purpose, including the focusing device.

[0015] One embodiment for addressing the aforementioned problems includes: a focusing device including micro-diffraction elements configured to diffract incident light applied by a user into G focused beams; and an imaging device configured to receive the G focused beams focused by the micro-diffraction elements of the focusing device and convert the received beams into electrical signals, wherein each micro-diffraction element belongs to one of the G groups, the micro-diffraction element belonging to the g-th group of the G groups generates the g-th focused beam, the density distribution of the micro-diffraction elements belonging to the g-th group is adjustable to apply an arbitrary intensity distribution to the g-th focused beam before it is focused, the position of the micro-diffraction elements belonging to the g-th group is adjustable to apply an arbitrary wavefront to the g-th focused beam before it is focused, and G is configured to be 2 or greater, and includes an optical system capable of measuring the intensity distribution and wavefront of the incident light.

[0016] In one embodiment, the micro-diffraction element includes a microstructure that causes diffraction in the direction of reflection or transmission, the microstructure including a micro-diffraction mirror, a micro-pinhole, etc.

[0017] In one embodiment, G focused beams, focused by the micro-diffraction elements of the focusing device, are focused at different positions on a single focal plane.

[0018] In one embodiment, the coordinates of the nth micro-diffraction element in the g-th group are arranged... The conditions are determined such that the positions of the micro-diffraction elements do not overlap, and simultaneously the phase error is determined by the following equation ( As close to 0 as possible in, It is a light source With the nth micro-diffraction element belonging to group g The distance between them can be calculated using the following equation: It is the nth micro-diffraction element belonging to group g. The focal point of the g-th focused beam The distance between them can be calculated using the following equation: It is a light source Center point of the focusing device The distance between them can be calculated using the following equation: It is the center of the focusing device The focal point of the g-th focused beam The distance between them can be calculated using the following equation: m It is a non-negative integer. k It is the wavenumber of the incident light, and is a value obtained by dividing the product of 2π and the refractive index of the space through which the light passes by the center wavelength of the light. It is an arbitrary wavefront function applied to the g-th focused beam before it is focused by the micro-diffraction elements belonging to the g-th group.

[0019] In one embodiment, the size of the micro-diffraction element is determined such that the phase error within the nth micro-diffraction element belonging to the gth group ( The change in ) is less than that of π.

[0020] In one embodiment, the intensity of the G focused beams can be adjusted by changing the size of the micro-diffraction element.

[0021] In one embodiment, one or more pairs of focused beams in the G focused beams apply wavefront functions with opposite signs to each other, such that the wavefront information of the incident light can be identified without a separate reconstruction process.

[0022] In one embodiment, wavefronts can be reconstructed using G focused beams or a portion thereof, employing methods such as coherent diffraction imaging reconstruction.

[0023] In one embodiment, in the portion of the focusing device where there are no micro-diffraction elements, some or all of the incident light is absorbed, transmitted, or reflected, so that the incident light can be used for another purpose.

[0024] In one embodiment, a relationship is established between wavefronts measured using two or more focusing devices, and using the established relationship, the intensity distribution and wavefront information of the incident laser beam at a location expected to be measured by another focusing device can be inferred from the intensity distribution and wavefront information measured at any of the two or more focusing devices, and includes an optical system.

[0025] Beneficial effects The present invention provides a light-concentrating device that can focus incident light into multiple focused beams with arbitrary intensity distribution and arbitrary wavefront.

[0026] The present invention provides an optical system that can measure the intensity distribution and wavefront information of incident light by focusing incident light into multiple focused beams having arbitrary intensity distribution and arbitrary wavefront.

[0027] The light-concentrating device of the present invention is easy to manufacture on a large scale and directly focuses the incident light into a focused beam, thus eliminating the need for additional optical instruments such as telescopes, focusing lenses or focusing mirrors.

[0028] The focusing device and optical system of the present invention utilize the diffraction effect to perform measurements using only a portion of the incident light, so that the undiffracted incident light can be used for another purpose.

[0029] The focusing device and optical system of the present invention utilize the diffraction effect to perform measurements using only a portion of the incident light, thereby reducing the intensity of the incident laser beam. Therefore, it is unnecessary to adjust the intensity of the incident laser beam, and additional optical instruments for intensity adjustment can also be avoided. Attached Figure Description

[0030] Figure 1This is a diagram illustrating an optical system including a focusing device according to an embodiment of the present invention.

[0031] Figure 2 It is shown Figure 1 A diagram showing the distances and coordinates of the various components in the optical system.

[0032] Figure 3 This is a diagram showing the first (g=1) group of contour lines of the first (g=1) group of micro-diffraction elements arranged in a focusing device according to an embodiment of the present invention.

[0033] Figure 4 This shows multiple micro-diffraction elements arranged in Figure 3 A diagram showing the state of the focusing device.

[0034] Figure 5 This is a diagram illustrating an optical system including a focusing device arranged in various ways, according to various embodiments of the present invention.

[0035] Figure 6 This is a diagram illustrating multiple optical systems according to an embodiment of the present invention for establishing a relationship between two optical systems and inferring a measurement value from one location to another.

[0036] Figure 7 This is a diagram showing the focal point when focusing aberration-free incident light using the optical system of the present invention.

[0037] Figure 8 This is a diagram showing the focal point when focusing incident light with vertical astigmatism using the optical system of the present invention. Detailed Implementation

[0038] In the following description, embodiments of the invention will be clearly and in detail to enable those skilled in the art to readily practice the invention.

[0039] Figure 1 This is a diagram illustrating an optical system including a focusing device according to an embodiment of the present invention.

[0040] Reference Figure 1 The optical system 100 may include a focusing device PSV and an imaging device IMD.

[0041] The incident light IL emitted from the light source LS can propagate toward the focusing device PSV.

[0042] A focusing device (PSV) can be configured to receive incident light IL. The PSV may include multiple micro-diffraction elements configured to diffract the incident light IL. These micro-diffraction elements can be arranged to diffract the incident light IL and focus the diffracted light to multiple focal points. Each micro-diffraction element contributes to focusing one of G focused beams. Therefore, the multiple micro-diffraction elements can be divided into G groups. In this embodiment, for convenience, it is assumed that G=2, i.e., the case of two focused beams.

[0043] exist Figure 1 In the illustrated embodiment, for convenience, the plurality of micro-diffraction elements belonging to the first group (g=1) are referred to as the first micro-diffraction element DEp1, the plurality of contour lines on which the first micro-diffraction element can lie are referred to as the first contour line CTL1, the focused beam focused by the first micro-diffraction element is referred to as the first focused beam, and the point where the first focused beam is focused is referred to as the first focal point FCp1. Similarly, for the second group (g=2), the corresponding elements are referred to as the second micro-diffraction element DEp2, the second contour line CTL2, the second focused beam, and the second focal point FCp2, respectively.

[0044] The focusing device PSV includes multiple first micro-diffraction elements DEp1 and multiple second micro-diffraction elements DEp2.

[0045] Light diffracted by multiple micro-diffraction elements of the focusing device PSV can be focused onto the same focal plane FPL. For example, incident light IL can be diffracted by the first micro-diffraction element DEp1 and focused at a first focal point FCp1 on the focal plane FPL, and incident light IL can also be diffracted by the second micro-diffraction element DEp2 and focused at a second focal point FCp2 on the focal plane FPL. The first focal point FCp1 and the second focal point FCp2 can have different coordinates on the focal plane FPL and can be separated from each other. In this specification, "focusing" of light means converging light within a finite space on the focal plane FPL. In this specification, a focal point refers to the diffracted light being focused into a predetermined area.

[0046] exist Figure 1 In this context, microdiffraction elements are distinguished by being represented as circles or triangles according to their group; however, the form of microdiffraction elements is not restricted. That is, all microdiffraction elements can be manufactured in the same shape.

[0047] An imaging device (IMD) can be configured to capture a light beam focused on a focal plane (FPL). The IMD can be configured to receive the light beam focused at a first focal point (FCp1) and a second focal point (FCp2), and convert the received light beam into an electrical signal for output. The IMD can also be configured to output the electrical signal to an external computing device.

[0048] In the following text, reference will be made to Figure 2 or Figure 3 A method for determining the position of a first micro-diffraction element DEp1 on a focusing device PSV is described in detail. The first micro-diffraction element DEp1 is used to apply an arbitrary intensity distribution and an arbitrary wavefront to the input light and focus the input light at a first focal point FCp1.

[0049] To explain the process of applying arbitrary wavefronts, Figure 2 The definition of the distance between the light source LS, the micro-diffraction element, and the focal point is shown. Figure 2 The diagram also illustrates the case where the input light IL incident from the light source LS is diffracted by the first micro-diffraction element DEp1 and focused at the first focal point FCp1 (i.e., g=1). For example... Figure 2 As shown, the x, y, and z axes can be defined by referring to the surface of the focusing device PSV where micro-diffraction elements are distributed. Furthermore, the distance between the light source LS and the center of the focusing device PSV is defined as... The distance between the light source LS and the nth micro-diffraction element in the first micro-diffraction element DEp1 is defined as The distance between the first focal point FCp1 and the nth micro-diffraction element in the first micro-diffraction element DEp1 is defined as The distance between the center point of the focusing device PSV and the first focal point FCp1 is defined as .like Figure 2 As shown, the light source LS or imaging device IMD does not need to be located on the z-axis relative to the focusing device PSV; any position is possible.

[0050] The coordinates of the light source LS that emits incident light IL can be defined as follows: .

[0051] The coordinates of the nth first micro-diffraction element in the first group (g=1) of the first micro-diffraction elements DEp1 used for focusing the incident light IL can be defined on the xy plane at z=0 as The coordinates of the center point Cp of the focusing device PSV can be defined as follows: The coordinates of the first focus FCp1 on the focal plane FPL can be defined as follows: .

[0052] The first profile CTL1 of the first micro-diffraction element DEp1 arranged on the focusing device PSV can be based on the phase error of the nth micro-diffraction element belonging to the first group (g=1). ) is specified according to (Equation 1) below.

[0053] (Equation 1) In (Equation 1), It is a light source LS With the nth first micro-diffraction element The distance between them can be calculated using the following equation (2).

[0054] (Equation 2) In (Equation 1), It is the nth first micro-diffraction element With the first focus The distance between them can be calculated using the following equation (3).

[0055] (Equation 3) In (Equation 1), It is a light source LS Center point of the focusing device PSV The distance between them can be calculated using the following equation (4).

[0056] (Equation 4) In (Equation 1), It is the center point of the PSV (Power Photoconcentrator). With the first focus FCp1 The distance between them can be calculated using the following equation (5).

[0057] (Equation 5) In (Equation 1), m It is a non-negative integer and satisfies the phase error. The set of points presents the form of multiple contour lines. Therefore, the position of the first micro-diffraction element DEp1 on the focusing device PSV, which belongs to g=1, satisfies... The position, present Figure 2 The outline CTL1 shown on the focusing device in the image is in the form of the light-gathering device.

[0058] In (Equation 1), k It is the wavenumber of the input light IL, and is a value obtained by dividing the product of 2π and the refractive index of the space through which the light passes by the center wavelength of the light.

[0059] In (Equation 1), the wavefront function It is a function representing the arbitrary wavefront shape additionally applied to the first focused beam focused by the first micro-diffraction element, and can be expressed by the following (Equation 6).

[0060] (Equation 6) In (Equation 6), the wavefront information function It can be expressed as a Zernike polynomial or, equivalently, as a sum of wavefront basis functions representing the characteristic shape of the wavefront, where, It is the basis function of the h-th wavefront. It is the amplitude of the h-th wavefront basis function of the wavefront applied to the first focused beam by the first micro-diffraction element. See (Equation 6). It can be represented as the sum of (H+1) wavefront basis functions.

[0061] The coordinates of the nth first micro-diffraction element The phase error value can be determined as follows: the micro-diffraction elements do not overlap and (Equation 1) Coordinates that are as close to 0 as possible.

[0062] Phase error value in Equation 1 The coordinates of the first micro-diffraction element DEp1, which is as close to 0 as possible, can be determined based on the value of m ( =0, 1, 2, ...) are provided in the form of multiple contour lines, and the contour line on which the first micro-diffraction element DEp1 can be arranged can be defined as the first contour line CTL1.

[0063] Reference Figure 3 This describes a method for simultaneously applying an arbitrary intensity distribution while positioning multiple first micro-diffraction elements DEp1 on the first contour line CTL1 of a focusing device PSV. For example, it can be assumed that on the focusing device PSV, the incident light only... x The portion x < 0 is diffracted to produce a focused beam. To apply such an intensity distribution, a virtual first micro-diffraction element is uniformly distributed in the x < 0 portion of the focusing device PSV at its initial position DEp1', and then moved from these positions to the nearest first contour line CTL1 to determine the position of the first micro-diffraction element DEp1, which minimizes phase error while having the desired intensity distribution. Here, a simpler example is described: half of the incident light (x < 0) passes through, while the other half is not allowed to pass through. However, by adjusting the density distribution of the micro-diffraction elements, an arbitrary intensity distribution can be applied to the incident light.

[0064] Reference Figure 4 This section describes a method for positioning micro-diffraction elements that generate multiple focused beams. It can be assumed that the second micro-diffraction element generates the focused beam by diffracting only in the region where y < 0. (See reference...) Figure 3 As described above, after positioning the first micro-diffraction element DEp1 on the first contour line CTL1, as Figure 4As shown, the second micro-diffraction element can be positioned on the second contour line in the same manner. At this point, the position can be adjusted so that the micro-diffraction elements do not overlap. By utilizing the degrees of freedom in position adjustment, micro-diffraction elements that generate multiple focused beams can be arranged. For example... Figure 4 As shown, the center point CT1 of the first contour line CTL1 and the center point CT2 of the second contour line CTL2 on the focusing device PSV may not coincide with each other.

[0065] Reference Figure 5 This paper describes a method for simultaneously using incident light IL for another purpose and measuring the intensity distribution and wavefront of the incident light IL. The focusing device PSV can be configured such that the incident light is reflected or transmitted in the portion where the micro-diffraction elements are not located. Alternatively, the diffracted focused beam can also be configured to be reflected or transmitted. Therefore, the following are possible: Figure 5 As shown in (A), the incident light is transmitted and the focused beam that has been diffracted is reflected; as Figure 5 As shown in (B), the incident light is transmitted and the focused beam that has been diffracted is also transmitted; as Figure 5 As shown in (C), the incident light is reflected and the focused beam diffracted is reflected; and as Figure 5 As shown in (D), the incident light is reflected and the diffracted focused beam is transmitted. In each case, the diffracted focused beam can be used to measure the intensity distribution and wavefront of the incident light, while the reflected or transmitted incident light can be used for another purpose.

[0066] Reference Figure 6 This will describe a method for measuring the intensity distribution and wavefront of incident light using multiple focusing devices. For example... Figure 6 As shown, an optical system can be designed using multiple focusing devices. In this embodiment, assuming the use of a focusing mirror FM, the incident light IL is focused at a focal point F and used for another purpose. The intensity distribution and wavefront of the incident light can be measured using a first focusing device PSV1 and an imaging device IMD1. Additionally, the intensity distribution and wavefront of the incident light IL can be measured using a second focusing device PSV2 and an imaging device IMD2. Therefore, it is possible to understand how the incident light IL changes as it passes through the two focusing devices PSV1 and PSV2. When the user uses the incident light for another purpose at focal point F, the second focusing device PSV2 may not be usable. Even so, after measuring the intensity distribution and wavefront of the incident light using the first focusing device, the intensity distribution and wavefront shape of the incident light at PSV2 can be inferred by considering the differences measured between the two focusing devices.

[0067] The focusing device PSV according to the present invention is not limited to the first focal point FCp1 and the second focal point FCp2, and may further include G groups of micro-diffraction elements that generate G focal points. Therefore, according to an embodiment of the present invention, multiple focal points can be formed by a single focusing device PSV. Reference will be made below. Figure 7 and Figure 8 The advantages of the present invention in forming multiple focal points are described.

[0068] Figure 7 This is a diagram showing the focal point when focusing aberration-free incident light using the optical system of the present invention. Figure 8 This is a diagram showing the focal point when focusing incident light with vertical astigmatism using the optical system of the present invention.

[0069] Reference Figure 7 and Figure 8 The optical system 100 of the present invention corresponds to the case of G=25 and can form 25 focused beams with different wavefronts.

[0070] In one embodiment, it is assumed that the beam size on the focusing device PSV is 25 mm, the distance between the focusing device PSV and the focal plane FPL is 500 mm, and the center wavelength of the light is 800 nm.

[0071] To create a focal point with 25 different aberrations on the focal plane FPL, use the values ​​shown in Table 1 below.

[0072] (Table 1)

[0073] Each group used approximately 15,100 micro-diffraction elements (circular micro-apertures). For beams with g=1 and g=5, the beam spread was large and the intensity was weak, so the number of micro-diffraction elements was doubled to increase the intensity. To achieve a similar effect, the same result could be obtained by changing the size of the micro-diffraction elements rather than changing the number of micro-diffraction elements.

[0074] In one embodiment, the wavefront applied to the g-th focused beam in Table 1 Zernike polynomial indexed by the h-th OSA / ANSI Composition, that is ,in, This corresponds to the amplitude applied to each Zernike polynomial.

[0075] In one embodiment, the coordinates of the focus point can be changed to adjust the position of the focused beam. Alternatively, the coordinates of the focus point can be... Set it to 0, and change it to correspond to the wavefront tilt. Z1 (vertical tilt) and (Horizontal tilt) amplitude value and These two methods for determining the position of the focused beam are mathematically equivalent.

[0076] In one embodiment, by changing the coordinates of the focus The location of the focal point is determined by stacking multiple wavefront basis functions to apply the desired wavefront. However, in one embodiment, only one wavefront basis function is used for each group. The focal point generated on the focal plane (FPL) using the values ​​shown in Table 1 can be calculated using the Fresnel-Huygens formula.

[0077] The focal point of the incident light when there are no aberrations, such as Figure 7 As shown in Table 1, since different aberrations were applied to the 25 beams, it can be confirmed that the shape of the focal point differs from each other depending on the applied wavefront. The focal point in the case of incident light with perpendicular astigmatism is shown below. Figure 8 As shown.

[0078] In the 25 focal points, the light corresponding to g=8 and the light corresponding to g=9 are constructed to impose astigmatism with opposite signs on each other.

[0079] Reference Figure 8 When the incident light has positive astigmatism, it can be seen that the light with g=9, which has been subjected to positive astigmatism, has a further distorted shape, while the light with g=8, which has been subjected to negative astigmatism, cancels out the positive astigmatism to produce a more focused focal point.

[0080] Therefore, in one embodiment of the invention, since the aberrations present in the incident light and the magnitude of the aberrations can be determined directly when viewing the 25 focused beams immediately, the effect of information acquisition can be enhanced.

[0081] Additionally, refer to Figure 7 and Figure 8 The beams corresponding to g=1 to g=5 are designed to have slightly different defocus values ​​from each other. In this way, the intensity distribution and wavefront of the incident light can be reconstructed using coherent diffraction imaging methods, which reconstruct the wavefront by using focused light with different defocus values ​​or different applied wavefronts.

[0082] The foregoing describes specific embodiments for carrying out the present invention. The present invention includes not only the embodiments described above, but also implementations that can be easily modified or altered in design. Furthermore, the present invention will also include techniques that can be easily modified and implemented using the embodiments. Therefore, the scope of the present invention should not be limited to the embodiments described above, but should be defined by the set forth claims and their equivalents.

Claims

1. A focusing device comprising a micro-diffraction element configured to diffract incident light applied by a user into G focused beams, wherein, Each of the micro-diffraction elements belongs to one of the G groups. The micro-diffraction element belonging to the g-th group among the G groups produces the g-th focused beam. The density distribution of the micro-diffraction elements belonging to the g-th group is adjustable to apply an arbitrary intensity distribution to the g-th focused beam before it is focused. The position of the micro-diffraction elements belonging to the g-th group is adjustable to apply an arbitrary wavefront to the g-th focused beam before it is focused, and G is configured to be 2 or greater.

2. The concentrating device according to claim 1, wherein, The micro-diffraction element includes a microstructure that induces diffraction in the reflection or transmission direction, the microstructure including a micro-diffraction mirror and a micro-pinhole.

3. The concentrating device according to claim 1, wherein, The G focused beams, focused by the micro-diffraction element of the focusing device, are focused at different positions on a single focal plane.

4. The concentrating device according to claim 1, wherein, The coordinates of the nth micro-diffraction element belonging to the gth group of micro-diffraction elements are arranged. The conditions are determined such that the positions of the micro-diffraction elements do not overlap, and simultaneously such that the phase error is determined by the following equation. As close to 0 as possible in, It is a light source With the nth micro-diffraction element belonging to the gth group The distance between them can be calculated using the following equation: in, It is the nth micro-diffraction element belonging to the gth group. With the focal point of the g-th focused beam The distance between them can be calculated using the following equation: in, It is the distance between the center point of the light source and the center point of the focusing device, and is calculated using the following equation: in, It is the center of the focusing device. With the focal point of the g-th focused beam The distance between them can be calculated using the following equation: in, m It is a non-negative integer. k It is the wavenumber of the incident light and is a value obtained by dividing the product of 2π and the refractive index of the space through which the light passes by the center wavelength of the light. in, It is an arbitrary wavefront function applied to the g-th focused beam before it is focused by the micro-diffraction elements belonging to the g-th group.

5. The concentrating device according to claim 1, wherein, The size of the micro-diffraction element is determined such that the phase error within the nth micro-diffraction element belonging to the gth group is... The change is less than π.

6. The concentrating device according to claim 1, wherein, The intensity of the G focused beams can be adjusted by adjusting the size of the micro-diffraction element.

7. The concentrating device according to claim 1, wherein, One or more of the G focused beams apply wavefront functions with opposite signs to each other, so that the wavefront information of the incident light can be identified without a separate reconstruction process.

8. The concentrating device according to claim 1, wherein, Using the G focused beams or a portion thereof, the intensity distribution and wavefront of the incident light can be reconstructed through coherent diffraction imaging reconstruction methods.

9. The concentrating device according to claim 1, wherein, In the portion of the focusing device where there are no micro-diffraction elements, part or all of the incident light is absorbed, transmitted, or reflected, so that the incident light can be used for another purpose, including the focusing device itself.

10. An optical system, comprising: A focusing device, including micro-diffraction elements configured to diffract incident light applied by a user into G focused beams; as well as An imaging device is configured to receive the G focused beams focused by the micro-diffraction element of the focusing device and convert the received beams into electrical signals. in, Each of the micro-diffraction elements belongs to one of the G groups. Among them, the micro-diffraction element belonging to the g-th group of the G groups produces the g-th focused beam. The density distribution of the micro-diffraction elements belonging to the g-th group is adjustable to apply an arbitrary intensity distribution to the g-th focused beam before it is focused. The position of the micro-diffraction element belonging to the g-th group is adjustable to apply an arbitrary wavefront to the g-th focused beam before it is focused. Where G is configured to be 2 or greater, and The optical system is capable of measuring the intensity distribution and wavefront of the incident light.

11. The optical system according to claim 10, wherein, The micro-diffraction element includes a microstructure that induces diffraction in the reflection or transmission direction, the microstructure including a micro-diffraction mirror and a micro-pinhole.

12. The optical system according to claim 10, wherein, The G focused beams, focused by the micro-diffraction element of the focusing device, are focused at different positions on a single focal plane.

13. The optical system according to claim 10, wherein, The coordinates of the nth micro-diffraction element belonging to the gth group of micro-diffraction elements are arranged. The conditions are determined such that the positions of the micro-diffraction elements do not overlap, and simultaneously such that the phase error is determined by the following equation ( As close to 0 as possible in, It is a light source With the nth micro-diffraction element belonging to the gth group The distance between them can be calculated using the following equation: in, It is the nth micro-diffraction element belonging to the gth group. With the focal point of the g-th focused beam The distance between them can be calculated using the following equation: in, The light source With respect to the center point of the focusing device The distance between them can be calculated using the following equation: in, It is the center of the focusing device. With the focal point of the g-th focused beam The distance between them can be calculated using the following equation: in, m It is a non-negative integer. k It is the wavenumber of the incident light and is a value obtained by dividing the product of 2π and the refractive index of the space through which the light passes by the center wavelength of the light. in, It is an arbitrary wavefront function applied to the g-th focused beam before it is focused by the micro-diffraction elements belonging to the g-th group.

14. The optical system according to claim 10, wherein, The size of the micro-diffraction element is determined such that the phase error within the nth micro-diffraction element belonging to the gth group is... The change is less than π.

15. The optical system according to claim 10, wherein, The intensity of the G focused beams can be adjusted by adjusting the size of the micro-diffraction element.

16. The optical system according to claim 10, wherein, One or more of the G focused beams apply wavefront functions with opposite signs to each other, so that the wavefront information of the incident light can be identified without a separate reconstruction process.

17. The optical system according to claim 10, wherein, The wavefront can be reconstructed using the G focused beams or a portion thereof through a coherent diffraction imaging reconstruction method.

18. The optical system according to claim 10, wherein, In the portion of the focusing device where there are no micro-diffraction elements, part or all of the incident light is absorbed, transmitted, or reflected, so that the incident light can be used for another purpose.

19. The optical system according to claim 10, wherein, A relationship is established between wavefronts measured using two or more focusing devices, and using the established relationship, the intensity distribution and wavefront information of the incident laser beam at the location expected to be measured by another of the two or more focusing devices can be inferred from the intensity distribution and wavefront information measured at any one of the two or more focusing devices.

Images