KR20200078105A - System and method of measuring performance of light - Google Patents

Abstract

Disclosed are an optical performance measurement system and method capable of measuring a beam spot profile at high speed. According to the present invention, the optical performance measurement system comprises an array detector having a plurality of pixels. The pixels are arranged in two dimensions (2D). A beam is projected to the pixels, and beam intensity or a change in the beam intensity is measured for each pixel to obtain a beam spot profile.

Description

System and method for measuring optical performance{SYSTEM AND METHOD OF MEASURING PERFORMANCE OF LIGHT}

The present invention relates to a system and method capable of measuring a beam profile at high speed.

When measuring beam performance, spot size, energy distribution, phase distribution, divergence angle, etc. are important measures as performance parameters. Among the performance parameters, the beam spot profile can be measured through the Knife Edge Scanning method.

1 is a view showing a conventional Knife Edge Scanning method.

1, in a structure in which a beam is irradiated with a photo detector, a blade is positioned between the beam output device and the photo detector.

As shown in (a) to (c) of Figure 1, the blade is moved, the intensity of the beam detected by the photo detector is changed according to the movement of the blade. That is, the intensity of the beam is changed according to the movement of the blade, and the beam spot profile e can be obtained through the change of the intensity of the beam.

In order to use the Knife Edge Scanning method, the blade needs to be moved, but since the number of sampling is large, it is necessary to precisely move the blade and the scanning range corresponds to the size of the beam spot, so it took a long time to measure the beam spot profile. . That is, the beam spot profile measurement speed is slow. In addition, with this Knife Edge Scanning method, only a 1D beam spot profile can be obtained in one scan.

KR 10-1890358 B

The present invention provides an optical performance measurement system and method capable of measuring a beam spot profile at high speed.

In order to achieve the above object, the optical performance measurement system according to an embodiment of the present invention includes an array detector having a plurality of pixels, wherein the pixels are arranged in 2D, and a beam is irradiated to the pixels , A beam spot profile is obtained by measuring a beam intensity or a change in beam intensity for each pixel.

A method of measuring optical performance according to an embodiment of the present invention includes irradiating a beam with an array detector having a plurality of pixels; And measuring a beam intensity or a beam intensity change for each pixel as the beam is irradiated. Here, the pixels are arranged in 2D, and a beam spot profile is obtainable through a change in intensity or intensity of the measured beam.

In the present invention, since the optical performance measurement system uses an array detector made of a plurality of pixels without using a blade, it is possible to measure a beam spot profile at high speed and obtain a 3D beam spot profile in one scan.

1 is a view showing a conventional Knife Edge Scanning method.
2 is a view schematically showing an optical performance measurement system according to an embodiment of the present invention.
3 is a view showing a c-row beam spot profile according to an embodiment of the present invention.
4 is a diagram illustrating changes in intensity for each pixel according to an x-axis scan.
5 is a diagram illustrating intensity and beam profiles for each pixel according to an embodiment of the present invention.

As used herein, a singular expression includes a plural expression unless the context clearly indicates otherwise. In this specification, the terms "consisting of" or "comprising" should not be construed as including all of the various components, or various steps described in the specification, among which some components or some steps It may not be included, or it should be construed to further include additional components or steps. In addition, terms such as "... unit" and "module" described in the specification mean a unit that processes at least one function or operation, which may be implemented in hardware or software, or a combination of hardware and software. .

The present invention relates to an optical performance measurement system, it is possible to measure the beam spot profile (beam spot profile) at high speed.

In the conventional knife edge scanning method, the beam spot profile must be measured by precisely moving the blade for multiple sampling, so it takes a lot of time to measure the beam spot profile and can acquire only the 1D beam profile. In addition, since the scan range is the beam spot size, the scan speed is slow.

On the other hand, the optical performance measurement system of the present invention uses a 2D array detector instead of a blade, and the beam spot profile is measured by linearly moving the 2D array detector in a step format (pixel unit), so that precise movement like a blade is possible. Since it is not necessary, the time for measuring the beam spot profile is reduced, so that the beam spot profile can be measured at a high speed and a 3D beam profile can be obtained. In addition, since the scan range of the 2D array detector is a pixel size, scanning speed may be fast.

Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a view schematically showing an optical performance measurement system according to an embodiment of the present invention, and FIG. 3 is a view showing a c-row beam spot profile according to an embodiment of the present invention. 4 is a diagram illustrating a change in intensity for each pixel according to an x-axis scan, and FIG. 5 is a view showing intensity and beam profile for each pixel according to an embodiment of the present invention.

2, the optical performance measurement system of the present embodiment includes a 2D array detector 200, but the array detector 200 may be formed of a plurality of pixels. That is, the pixels of the array detector 200 are arranged in 2D, for example, may have the same size. Here, the size of the pixel may vary depending on the design.

For measuring optical performance, a beam (eg, a laser) is irradiated to the array detector 200 as shown in FIG. 2, and a beam spot is formed on the array detector 200.

According to one embodiment, as the beam output device is fixed, the beam is fixed and irradiated, and the array detector 200 may sequentially move, for example, in units of pixels, as described below, to obtain a beam spot profile. Of course, the array detector 200 may be fixed and the beam output device may be moved, but the structure may be more complicated than when the beam output device is fixed and the array detector 200 is moved.

On the other hand, although not mentioned, the array detector 200 may move automatically or manually according to a setup program. As long as the array detector 200 moves in a predetermined unit, the structure for moving the array detector 200 may be variously modified.

According to an embodiment, the array detector 200 measures the intensity of a beam per pixel, detects a change in intensity of a beam per pixel according to the movement of the array detector 200, and changes the intensity of the detected beam Through this, a 3D beam spot profile can be obtained.

In summary, the optical performance detection system of this embodiment measures the intensity of a beam for each pixel using an array detector 200 made of pixels arranged in 2D, and moves the array detector 200 in a predetermined unit to perform pixel-by-pixel detection. The intensity change of the beam is measured, and a beam spot profile can be obtained through the measured intensity change of the beam.

According to another embodiment, the optical performance detection system may further include an analysis unit. In this case, the array detector detects the beam for each pixel, and the analyzer can measure the intensity and intensity change of the beam for each pixel and obtain a beam spot profile.

Hereinafter, the beam performance measurement process of the present invention will be described.

Looking at the c-row scan process, when the beam is irradiated to the array detector 200, the intensity of the beam irradiated with pixels (Ac, Bc, Cc, Dc, Ec, and Fc) of c-row is measured. The beam generally has a Gaussian distribution as shown in (a) of FIG. 3, but the intensity of the beam through the array detector 200 is measured pixel by pixel, so it can be recognized as DC as shown in (b) of FIG. 3. Can. As a result, when scanning row c, a beam spot profile can be obtained as shown in Fig. 3(c), and specifically, pixels of row c (Ac, Bc, Cc, Dc, Ec, and Fc) The beam intensities I _A0 , I _B0 , I _C0 ,I _D0 ,I _E0 ,I _F0 are as shown in FIG. 3C. Here, the reference point (x=0) may be a point where the Bc pixel and the Cc pixel meet, and the subscript '0' means the first scan.

This scan process may be performed on pixels in rows a, b, d, and e as well as c. That is, beam intensity may be simultaneously measured for all pixels of the array detector 200. Of course, as illustrated in FIG. 3, the reference point (x=0) may be a point where the Bc pixel and the Cc pixel meet.

In the conventional Knife Edge Scanning method, only a 1D beam spot profile can be measured, and multiple one-axis scans must be performed to obtain a 3D beam spot profile. On the other hand, when beam intensity measurement is performed on all the pixels in the optical performance measurement method of the present invention, a 3D beam spot profile as shown in FIG. 2 can be obtained through one axial scan.

Subsequently, a second scan is performed. 4(b), the reference point (x=0) moves to the left. For example, the array detector 200 moves in the left direction, and as a result, beam intensities I _A1 , I _B1 , and I _C1 of the pixels c, Bc, Cc, Dc, Ec, and Fc in row c ,I _D1 ,I _E1 ,I _F1 ). Here, the reference point (x=0) has moved into the Cc pixel, and the subscript '1' means the second scan.

In (b) of FIG. 4, green indicates the amount of beam increased in the corresponding pixel according to the movement of the array detector 200, and FIG. 4(c) shows pixels in rows c (Ac, Bc, Cc, Dc, Ec and Fc) is a graph showing average beam intensity (I _A1 , I _B1 , I _C1 ,I _D1 ,I _E1 ,I _F1 ). In (c) of FIG. 4, the red box indicates the intensity reduced than the intensity of the beam in the corresponding pixel before moving.

This scan process may be performed on pixels in rows a, b, d, and e as well as c. That is, beam intensity may be simultaneously measured for all pixels of the array detector 200.

Subsequently, after moving the array detector 200 in the leftward direction, the (N-1)-th scan is performed, and as a result, the beams of the pixels (Ac, Bc, Cc, Dc, Ec, and Fc) in the c row are The intensities I _AN , I _BN , I _CN , I _DN , I _EN , and I _FN are as shown in Figures 4(d) and (e).

This scan process may be performed on pixels in rows a, b, d, and e as well as c. That is, beam intensity may be simultaneously measured for all pixels of the array detector 200.

The intensity and degree of change of the beam according to the movement of the array detector 200 are shown in Equations 1 and 2 below, and the intensity of the beam for each pixel and the intensity change of the beam (beam spot profile) are shown in FIG. 5. .

Here, the I _Area represents the amount of change in beam intensity according to the movement of the array detector 200.

In the above, the movement of the array detector 200 is smaller than the size of the pixel, but is not limited thereto, and the intensity of the beam may be measured while the array detector 200 moves in units of pixels.

In summary, the optical performance measurement system of the present invention can obtain a beam spot profile by measuring the intensity of a beam for each pixel and a change in intensity of a beam while moving the array detector 200 made of pixels in steps. Therefore, the optical performance measurement system can accurately measure the beam spot profile at high speed.

On the other hand, the components of the above-described embodiments can be easily grasped from a process point of view. That is, each component can be identified by each process. Further, the process of the above-described embodiment can be easily grasped from the perspective of the components of the device.

In addition, the above-described technical contents may be recorded in a computer-readable medium by being implemented in the form of program instructions that can be executed through various computer means. The computer-readable medium may include program instructions, data files, data structures, or the like alone or in combination. The program instructions recorded on the medium may be specially designed and configured for the embodiments, or may be known and available to those skilled in computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical media such as CD-ROMs, DVDs, and magnetic media such as floptical disks. Includes hardware devices specifically configured to store and execute program instructions such as magneto-optical media, and ROM, RAM, flash memory, and the like. Examples of program instructions include high-level language code that can be executed by a computer using an interpreter, etc., as well as machine language codes produced by a compiler. The hardware device can be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

The above-described embodiments of the present invention are disclosed for the purpose of illustration, and those skilled in the art having various knowledge of the present invention will be able to make various modifications, changes, and additions within the spirit and scope of the present invention. It should be regarded as belonging to the following claims.

200: array detector

Claims (7)

An array detector having a plurality of pixels,
The pixels are arranged in 2D, the beam is irradiated to the pixels, and the intensity of the beam or the intensity change of the beam is measured for each pixel to obtain a beam spot profile. According to claim 1, The array detector is moved, the position where the beam is irradiated is varied, the intensity change of the beam according to the movement of the array detector is measured, the beam spot profile through the measured intensity change of the beam Optical performance measurement system, characterized in that obtained. 3. The optical performance measurement system according to claim 2, wherein a change in intensity of a beam is measured while the array detector moves in units of pixels. The optical performance measurement system according to claim 1, wherein a 3D beam spot profile can be obtained by measuring beam intensity for all pixels per scan. Irradiating a beam with an array detector having a plurality of pixels; And
Measuring the intensity of the beam or the intensity change of the beam for each pixel as the beam is irradiated,
The pixels are arranged in 2D, and a beam spot profile is obtainable through a change in intensity or intensity of the measured beam. The method of claim 5,
Moving the array detector;
Measuring the intensity of the beam irradiated by the moved array detector for each pixel;
And measuring a change in intensity of a beam for each pixel according to the movement to obtain a beam spot profile. The method of claim 6, wherein the intensity of the beam is measured while the array detector moves in units of pixels.

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