KR100977549B1 - System and Method of High Speed Measurement of Terahertz Wave - Google Patents

Abstract

The present invention relates to a method of acquiring and processing data at a high speed in a terahertz wave spectroscopy and imaging device, and to provide a means for faster analysis by acquiring and processing terahertz wave pulse information at high speed for various samples. It is. In the terahertz wave measuring system according to an aspect of the present invention, the laser beams separated by two paths in the beam splitter have a time difference by using optical delay means including a rotating reflector having a plurality of vanes. The laser beam is incident on the terahertz wave generating means and the terahertz wave detecting means, respectively, and is generated by the terahertz wave detecting means in a DAQ system that is activated when a trigger signal is generated from the means for controlling the optical delay means. A voltage signal corresponding to the current signal may be sampled to collect data of terahertz wave pulses for a sample between the terahertz wave generation means and the terahertz wave detection means.

Terahertz Wave, Measurement, Rotary Delay, Trigger Signal, DAQ, Stage Drive

Description

System and Method of High Speed Measurement of Terahertz Wave

The present invention relates to a terahertz wave measuring system and method, and more particularly, to measure real-time terahertz wave spectroscopy and high-speed terahertz wave imaging by measuring terahertz waves at high speed using an optical delay and a data acquisition system capable of high-speed scanning. A terahertz wave measurement system and method for enabling the same.

1 is a view for explaining a conventional terahertz wave measurement system 100. Referring to FIG. 1, the conventional terahertz wave measurement system 100 includes a system controller 110, an optical delay controller 120, a linear optical delay unit 130, a stage controller 140, an XY stage 150, and a tera Hertz wave generator 160, terahertz wave detector 170, current signal amplifier 171, chopper 172, lock-in amplifier 173, DAQ system 174, pulse laser generator 180, And a display unit 190, and in addition, a beam splitter, a mirror, and the like for distributing or setting a path of the laser beam generated by the pulse laser generator 180.

In order to measure very short terahertz wave pulses of less than 1 ps in time, a pump-and-probe sampling method is used. In FIG. 1, a beam emitted from a pulsed laser is divided into two paths by a beam splitter, one is used to generate a terahertz wave, and the other is used to measure a terahertz wave. ) use.

The terahertz wave generated by the terahertz wave generating antenna of the terahertz wave generating unit 160 reaches the terahertz wave measuring antenna of the terahertz wave detecting unit 170 via a sample. When the terahertz pulse is generated from the generating antenna, a voltage (or electric field) is applied to both ends of the measuring antenna by an electric field (or voltage) of the terahertz wave, and the detection laser beam is measured by the mirrors. When reaches, electron-hole pairs are generated on the antenna surface by the laser energy. This electron-hole pair is moved across the antenna by an electric field formed by terahertz waves, where a short instantaneous current flows and the current value is proportional to the voltage (or electric field) of the terahertz wave.

To know the electric field at each point of the terahertz wave, at any point when the terahertz wave reaches the metrology antenna, a laser beam with a pulse width much narrower than the terahertz wave is applied, By measuring the electric field, changing the time difference of the laser beam for measuring the terahertz wave, sampling the electric field values at each terahertz wave point, and finally connecting the sampled values, the terahertz wave pulse shape is identified. In this way, the optical delay unit 130 is used to adjust the time difference of the beam between the terahertz wave reaching the measurement antenna and the measurement antenna.

The conventional terahertz wave measurement system 100 uses a linear optical delay unit 130 in which two reflection mirrors are installed in a linear motor. The amount of movement of the beam by the linear optical delay unit 130 in the system controller 110 is used. In step by step, one terahertz wave pulse is measured.

The current signal for the terahertz wave generated by the measuring antenna is converted into a voltage signal by the current signal amplifier 171, and at several kHz with respect to the laser beam through the mechanical chopper 172 to improve the signal-to-noise ratio during measurement. While the modulated signal is synchronized with the lock-in amplifier 173, the terahertz wave signal is obtained by sampling and acquiring data from the data acquisition system 174. In this case, to measure one terahertz wave signal, data from about 1024 points is obtained, and it takes about 30 seconds to 1 minute. In addition, in order to obtain an image using terahertz waves, a sample is placed between the terahertz wave generator 160 and the detector 170 and is two-dimensionally formed using the XY stage 150 perpendicular to the direction in which the terahertz waves propagate. The terahertz wave at each pixel must be measured while scanning. In this case, after the system controller 110 sends a control signal to the stage controller 140 to move the XY stage 150 to a certain position, the system controller 110 controls the optical delay unit 120 to control the linear delay unit 120. In order to measure the overall waveform of the terahertz wave by giving a control signal to the) to drive the linear optical delay unit 130. By repeating this process, an image is obtained through the display unit 190 for the entire sample to be measured. In this case, when the number of pixels is large, a considerable time is required.

Accordingly, an object of the present invention is to solve the above-described problems, and an object of the present invention is to continuously measure a number of terahertz wave pulses using a trigger signal generated by a rotary optical delay controller, and a rotary optical delay device. The present invention provides a high-speed terahertz wave measurement system and method using a rotational optical delay device capable of drastically reducing the time for obtaining a terahertz wave image by controlling the rotational speed and the XY stage controller.

In addition, another object of the present invention is that the DAQ system is activated (triggered) by using a trigger signal generated by the optical delay controller, and the signal from the terahertz wave detector is measured by the DAQ system through a current signal amplifier to synchronize the synchronization. The present invention provides a system and method for measuring terahertz waves at high speed through a simple circuit without a mechanical chopper and a lock-certified circuit.

First, to summarize the features of the present invention, the terahertz wave measurement system according to an aspect of the present invention for achieving the object of the present invention, using a light delay means including a rotating reflector having a plurality of wings. The laser beams separated by the two paths in the beam splitter have a time difference, and the laser beams having the time difference are respectively incident on the terahertz wave generating means and the terahertz wave detecting means, and the means for controlling the optical delay means. In the triggered DAQ system, the voltage signal corresponding to the current signal generated by the terahertz wave detection means is sampled in the activated DAQ system, and the terahertz for the sample between the terahertz wave generation means and the terahertz wave detection means. Data of wave pulses can be collected.

The terahertz wave measurement system performs measurements on a plurality of terahertz wave pulses that are proportional to the waveform scan frequency based on the speed of rotating the rotatable reflector in response to the one trigger signal and the number of the plurality of vanes. can do.

The terahertz wave measurement system includes a rotation speed of a motor for rotating the rotating reflector, a sampling rate SR of the DAQ system determined based on a preselected optical delay length resolution Δl , a waveform scan frequency f _s , and a measurement pulse number n. Means for controlling the optical delay means and a system controller for controlling the DAQ system according to the speed RPM and the total number of measurement data Ntot .

The terahertz wave measuring system further includes a stage controller for holding the sample and a stage controller for driving the stage, and driving the stage in a horizontal or vertical direction through the stage controller, so as to respond to the trigger signal once. In response, a measurement of the terahertz wave pulse may be performed while moving by the horizontal spatial resolution with respect to the entire line of the sample divided by the vertical spatial resolution.

The system controller includes a preselected optical delay length resolution Δl , a waveform scan frequency f _s , a horizontal length l _x , a horizontal spatial resolution Δx, a vertical length l _y , and a vertical spatial resolution Δy . Based on the sampling rate SR of the DAQ system, the rotational speed RPM of the motor for rotating the rotary reflector, the total number of measured data Ntot , the horizontal speed v _x , the horizontal And determining the total number of pixels n _x and n _y in the vertical direction to control the optical delay means and the DAQ system for the predetermined region of the sample.

The terahertz wave measuring method according to another aspect of the present invention includes the steps of: separating the laser beam into two paths; Delaying any one of the laser beams such that the laser beams separated by the two paths have a time difference using optical delay means including a rotating reflector having a plurality of vanes; Injecting the laser beams having the time difference into the terahertz wave generating means and the terahertz wave detecting means, respectively; And a sample between the terahertz wave generation means and the terahertz wave detection means by sampling a voltage signal corresponding to the current signal generated by the terahertz wave detection means when a trigger signal is generated from the means for controlling the optical delay means. For example, the method includes collecting data of terahertz wave pulses.

The terahertz wave measuring method includes driving a stage for holding the sample in a horizontal or vertical direction, so as to have a horizontal spatial resolution for an entire line of the sample divided by vertical spatial resolution in response to the one trigger signal. The method may further include performing measurements on the terahertz wave pulses in increments.

According to the high-speed terahertz wave measurement system and method according to the present invention, it can be applied to a terahertz wave spectroscopy and imaging system to quickly characterize various materials requiring terahertz waves, and require terahertz waves. Real-time monitoring of various processes and spectroscopic images of various materials can be obtained in near real time.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. Like reference numerals in the drawings denote like elements.

2 is a view for explaining a terahertz wave measurement system 200 according to an embodiment of the present invention.

Referring to FIG. 2, the terahertz wave measurement system 200 according to an embodiment of the present invention includes a system controller 210, an optical delay controller 220, a rotary optical delay 230, a stage controller 240, XY stage 250, terahertz wave generator 260, terahertz wave detector 270, current signal amplifier 271, DAQ system 272, pulse laser generator 280, and display unit 290 It includes, in addition to the beam splitter 30, the mirrors (31, 32, 33) for the distribution or path setting of the laser beam generated by the pulse laser generator 180. Here, the terahertz wave measurement system 200 according to one embodiment of the present invention is distinguished from the conventional system that the chopper 172 and the lock-in amplifier 173 as shown in FIG. A rotary photodelay 230 is used instead, and the other components operate similar to the components of the system of FIG.

As shown in FIG. 3, the rotating optical delay unit 230 includes a rotating reflector 10 including a retroreflective surface 15, a motor 20 for rotating the rotating reflector 10, incident light, and reflected light. It may include an optical lens 40 for focusing. The beam splitter 30 may distinguish incident light incident on the retroreflective surface 15 and reflected light reflected from the retroreflective surface 15.

The rotatable reflector 10 is composed of a body 11 which is connected to the motor 20 and rotated, and a plurality of wings 12 extending radially from the body 11, respectively, and having a retro-reflective surface on the plurality of wings 12. 15 are formed respectively. The rotatable reflector 10 has a structure in which the optical path difference changes linearly with respect to the rotation angle during a predetermined time of rotation. For example, the optical path difference (photo-delay length) l obtained from one reflector wing can be regarded as the product of the radius r of the optical delay reflector 10 and the rotation angle Δθ ([math] Equation 1]. Here, Δθ is the rotation angle of the motor 20 axis, r is the radius of the rotation type optical delay unit, and substantially from the center, i.e., from the motor 20 axis to the end of the circular body 11 portion (on the body 11). Corresponds to the distance of the wing 12). Since the rotation length is rΔθ when the axis of the motor 20 rotates by the rotation angle Δθ, the optical path difference incident on the retroreflective surface 15 through the optical lens 40 is also determined by rΔθ. Is determined by. For example, the initial position A at which light is incident on the retroreflective surface 15 before the motor 20 axis rotates, and the same retroreflective surface after the motor 20 axis rotates by the rotation angle Δθ ( This is because the distance BA between the initial position A and the position B, which extends in the traveling direction of the light, from the initial position A is equal to the rotation length rΔθ of the axis of the motor 20.
When rotating the rotatable reflector 10, after the laser light is incident and reflected on any one of the plurality of retro-reflective surfaces 15, the other retro-reflective surface 15 adjacent in the direction opposite to the rotation direction is shown. Until the laser light is incident and reflected on the discontinuity, a discontinuous section may be generated in which the laser light is not reflected.

This discontinuity may cause signal discontinuity, and signal discontinuity may result in a decrease in signal size, a decrease in signal-to-noise ratio, or an increase in the rotational speed of the rotatable reflector 10 during the terahertz wave measurement. Since problems such as narrow spectral characteristics may be generated, as shown in FIGS. 4 and 5, the end direction 151 of any one of the plurality of retroreflective surfaces 15 and the direction opposite to the rotational direction are rotated. The starting point 152 of the other retroreflective surface 15 adjacent to each other is preferably formed to coincide with each other based on the traveling direction L of the laser light.

Accordingly, since the discontinuous section in which the laser light is not reflected from the retroreflective surface 15 is removed while the rotatable reflector 10 is rotated, signal disconnection does not occur, and thus, when measuring the terahertz wave, As the rotational speed of the rotating reflector 10 increases, problems such as a decrease in the size of a signal, a decrease in a signal-to-noise ratio, or a narrow spectral characteristic may be solved.

In order to remove the discontinuous section as described above, the end point 151 and the starting point 152 of the retroreflective surface 15 are not limited to each other, but a method of increasing the number of the wings 12 may be considered. As described above, when the number of the wings 12 is increased, the end point 151 of one of the retro-reflective surfaces 15 of the plurality of retro-reflective surfaces 15 is adjacent to the direction opposite to the rotation direction based on the traveling direction of the laser light. Coincides with the other retroreflective surface 15. That is, when the end point 151 of any one of the plurality of retroreflective surfaces 15 is projected based on the traveling direction of the laser light, the projection points are adjacent to each other in the opposite direction to the rotation direction. It is located on the retroreflective surface 15.

In addition, the body 11 of the rotary reflector 10, for the generation of a trigger signal for external synchronization periodically for the measurement of the speed and position of the rotary reflector 10 in the measurement system 200 and data acquisition, At least one trigger slot 18 is formed. The motor 20 is preferably a servo motor capable of low speed precision operation and high speed constant speed operation. In this way, by using a motor capable of low-speed precision operation and high-speed constant speed operation, not only accurate measurement as in the conventional linear optical retarder system is possible, but also high-speed operation enables high-speed data collection and greatly shortens the measurement time. can do.

The optical splitter 30 can increase the utilization efficiency of laser light by appropriately adjusting the reflection ratio. The optical lens 40 focuses the laser light to enter the retro-reflective surface 15 of the rotatable reflector 10 and serves to refocus the laser light reflected from the retro-reflective surface 15. The optical lens 40 minimizes dispersion of the laser light by focusing the laser light on a small radius of curvature in consideration of the change in the radius of curvature of the rotating reflector 10. Detailed description of the other rotating optical delay unit 230 is also well shown in the domestic patent application No. 10-2007-0113652.

Meanwhile, in FIG. 2, the system controller 210 determines the rotation speed of the servo motor 20 to which the reflector 10 of the rotary optical delay unit 230 is fixed and gives a control signal to the optical delay controller 220. The optical delay controller 220 may generate one trigger pulse per rotation of the motor 20 to operate the rotation type optical delay 230.

The number of reflector blades of the rotating optical delay unit 230 is N, the rotation speed per minute of the motor 20 is RPM, and the sampling rate of the DAQ system 272 is SR, and the optical delay that can be obtained from one reflector blade If the length is l , the optical delay length resolution Δl can be determined as shown in [Equation 1]. Here, the delay distance of the rotating optical delay unit 230 is a value obtained by multiplying the radius of the optical delay unit reflector 10 of the rotating optical delay unit 230 by the rotation angle, Δθ is the rotation angle of the motor, and r is the rotating optical delay unit. of the radius, f is the sampling time of the rotational frequency (revolution per second), △ t is a DAQ system 272 of the motor.

[Equation 1]

Therefore, by controlling the revolutions per minute of the motor 20 and the sampling rate of the DAQ system 272, it is possible to adjust the length resolution of the rotary optical delay unit.

Since one terahertz wave can be scanned from the reflector vanes of one rotating optical delay unit 230, the waveform scan frequency f _s (scan) in the case of the rotating optical delay unit 230 having N reflector vanes. / sec) is given by Equation 2.

[Equation 2]

△ l and f _s Equation 3 is satisfied.

&Quot; (3) "

In Equation 3, since r and N of the rotary optical delay unit 230 are given values, f _s And SR , Δl can be obtained.

The number N of _reflectors measured by the reflector blades of one rotating optical delay unit 230 is expressed by Equation 4 below.

&Quot; (4) "

Therefore, when measuring n pulses, the total number of measurement data N _tot is expressed by Equation 5 below.

[Equation 5]

The time resolution of gwangji smoke (230) δt, may be computed as shown in Equation 6 by using the distance resolution △ l.

&Quot; (6) "

In FIG. 2, in order to obtain information about a point of a sample without driving the XY stage 250, for example, when terahertz wave spectroscopy is performed, the terahertz wave is generated at high speed according to the procedure of FIG. 6. It can be measured.

Referring to FIG. 6, first, the optical delay length resolution Δl , the waveform scan frequency f _s , and the number of measurement pulses n are selected (S310), and the sampling rate SR , [] of the DAQ system 272 according to [Equation 1] [ The rotation speed RPM of the motor 20 according to Equation 2] and the total number of measured data Ntot DAQ according to [Equation 4] are determined (S320).

Accordingly, while the system controller 210 operates (S330), while the DAQ system 272 is in a standby state (S340), the optical delay controller 220 operates (S350) to drive the optical delay motor 20. It may be (S351). In this case, the optical delay controller 220 receives and outputs a trigger signal from the trigger slot 18 for activating data collection of the DAQ system 272 or adjusts a pulse width or voltage magnitude based on the trigger signal. The trigger signal may be generated (S352), and thus, the length resolution of the rotating optical delay unit 230 may be adjusted by controlling the sampling rate of the DAQ system 272.

Meanwhile, the laser beam generated by the pulse laser generator 280 is divided into two paths through the beam splitter 30, and the laser beams separated by two paths from the beam splitter are separated by the optical delay 230. The first mirror 31 enters one of the laser beams having a time difference into the terahertz wave generator 260, and the second mirror 32 and the third mirror 33 of the laser beams have a time difference. The other is incident to the terahertz wave detector 270.

Accordingly, the current signal amplifier 271 may convert the current signal for the terahertz wave generated by the antenna of the terahertz wave generator 260 and generated by the antenna of the terahertz wave detector 270 through the sample into a voltage signal. When the trigger signal as described above is generated (S341), the DAQ system 272 continuously samples each time the beam is reflected from the optical delay unit 230 with respect to the output of the current signal amplifier 271 and outputs the data. Collect (S360). As described above, in the present invention, a plurality of terahertz wave pulses are continuously measured with respect to one trigger signal by using the rotation of the reflector of the rotary optical delay unit 230 controlled by the rotary optical delay unit 220. To help.

The system controller 210 may process the data to be displayed on a predetermined display device based on the data collected by the DAQ system 272 (S370), and store the processed data in the predetermined storage device (S380). An image of the terahertz wave signal may be displayed through the unit 290 (S390).

On the other hand, in Figure 2, when driving the XY stage 250 to obtain information about the cross section of the sample, for example, to obtain a terahertz wave image, the moving speed of the sample and the rotating optical delay ( The scan rate of 230 and the sampling rate of the DAQ system 272 should be linked to each other.

X-axis (horizontal) length of l _x, x-axis (horizontal) △ x the spatial resolution of the direction of the direction referred to, y-axis (vertical) length of the direction l _y, y-axis (vertical) direction of the sample to be imaged In terms of the spatial resolution Δy , the total number of pixels n _x , n _y in the x and y directions is expressed by Equation 7 below.

[Equation 7]

Since one terahertz waveform must be obtained from each pixel while moving the sample in the x-axis direction, the waveform scan frequency f _s of the rotating optical delay unit 230 and the moving speed v _x in the x-axis direction of the sample are expressed by Equation 8 ] To satisfy the relation of.

[Equation 8]

The driving form of the XY stage 250 for moving the sample to obtain an image for the sample is to move the X-axis stage by l _x at a speed of v _{x in} the x direction and then move the Y-axis stage as shown in FIG. 7 or 8. It is preferable to repeat the operation of moving by y in the y direction. As shown in Figure 7, △ y after moves may be obtained, repeating the step of moving the right stage in the left terahertz wave, move while moving the right stage from left to right as shown in Figure 8 by the terahertz △ y after acquiring waveform Afterwards, the process of acquiring terahertz waveforms may be repeated by moving the stage from right to left.

When acquiring the data for the x-axis direction of a sample of length l _x in the n _x pixels to the spatial resolution of the △ x, by controlling DAQ system 272 is to acquire the signal of one line full by the trigger signal of one It is possible to improve the terahertz wave image acquisition speed for the entire sample.

At this time, the total number of data N _tot for one line is calculated as shown in [Equation 8].

[Equation 9]

N _tot data acquired through the DAQ system 272 is n _x as shown in FIG. Waveforms may be provided in the form of being divided corresponding to each pixel of the sample.

Two methods are available for processing the data thus obtained. For example, 1) a method of storing a full waveform corresponding to each pixel, and 2) representative values from the waveform corresponding to each pixel (e.g., maximum, minimum, maximum-minimum, maximum, minimum) of the waveform. There may be a method of storing only one data corresponding to one pixel by taking only the position where the value appears.

In the method of 1) above, various types of images can be obtained in the post-processing of data, but in the process of processing a large amount of data, data processing (storage) takes a long time and takes up a lot of memory. In the method of 2) above, only one image is obtained per pixel, so only one image can be obtained. However, since the amount of data is small, the data processing time is fast and the capacity of a storage device such as a memory is at least possible.

Hereinafter, referring to FIG. 10, a data acquisition process for driving the XY stage 250 to obtain information about a cross section of a sample, for example, to obtain a terahertz wave image, will be described. .

Referring to FIG. 10, first, the optical delay length resolution Δl , the waveform scan frequency f _s , the length l _x in the x-axis (horizontal) direction, the spatial resolution Δx in the x- axis (horizontal) direction , and the y-axis (vertical) direction The length l _y , the spatial resolution Δy in the y-axis (vertical) direction is selected (S710), and the sampling rate SR of the DAQ system 272 according to [Equation 1], and the motor according to [Equation 2] Rotational speed RPM) , DAQ total measured data number according to [Equation 5] and [Equation 9] Ntot , x-axis speed v _x and [Equation 7] of XY stage 250 according to [Equation 8] The total number of pixels n _x , n _y in the x and y directions is determined (S720).

Accordingly, while the system controller 210 operates (S730), the operation of the stage controller 240 is controlled (S740), and the stage controller 240 accordingly determines the corresponding speed of the XY stage 250 according to the determined speed as described above. It can be adjusted (S741). At this time, while the DAQ system 272 is in the standby state (S750), the optical delay controller 220 is operated (S760), can drive the optical delay motor 20 (S361), at this time, the optical delay controller ( 220 may generate a trigger signal for activating data collection of the DAQ system 272 (S362), wherein the trigger signal is associated with the revolutions per minute of the motor 20, and thus the DAQ system 272 The resolution of the rotating optical delay unit 230 may be adjusted by controlling the sampling rate of the optical waveguide.

Meanwhile, the current signal amplifier 271 may convert the current signal for the terahertz wave generated from the antenna of the terahertz generating unit and generated through the sample to the voltage of the terahertz detection unit into a voltage signal, and the above trigger signal is generated. In operation S751, the DAQ system 272 collects data by continuously sampling each time the beam is reflected from the optical delay unit 230 with respect to the output of the current signal amplifier 271 (S780). At this time, according to the speed control of the stage controller 240 as described above, the XY stage 250 moves the stage in the x-axis direction in the same manner as in FIG. 7 or 8, and the DAQ system 272 transmits data for the corresponding pixel. The collecting process may be repeated (S770, S780).

The system controller 210 may process the data to be displayed on a predetermined display device based on the data collected by the DAQ system 272 (S781), and store the processed data in the predetermined storage device (S790). The display unit 290 may display an image of the terahertz wave signal (S791). In addition, the stage is moved by △ y in the y-axis direction under the control of the stage controller 240 repeats the above process for the next line (S792). As described above, the same process as described above may be repeated n _y times to complete the measurement of the entire sample (S793).

As described above, in the present invention, a plurality of terahertz wave pulses are continuously measured with respect to one trigger signal by using the rotation of the reflector of the rotary optical delay unit 230 controlled by the rotary optical delay unit 220. In particular, by controlling the rotational speed of the rotary optical delay unit 230 and the XY stage controller 240 in conjunction with it, it is possible to drastically reduce the time to obtain a terahertz wave image.

As described above, the present invention has been described by way of limited embodiments and drawings, but the present invention is not limited to the above embodiments, and those skilled in the art to which the present invention pertains various modifications and variations from such descriptions. This is possible. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the claims below but also by the equivalents of the claims.

1 is a view for explaining a conventional terahertz wave measurement system 100.

2 is a view for explaining a terahertz wave measurement system 200 according to an embodiment of the present invention.

3 is a view for explaining a rotation type optical delay device according to an embodiment of the present invention.

4 is a view for explaining a reflector of a rotary optical delay device according to an embodiment of the present invention.

5 is a view for explaining a reflector of a rotary optical delay unit according to an embodiment of the present invention.

FIG. 6 is a flowchart illustrating a terahertz wave measurement process in the case of obtaining information about a point of a sample without driving the X-Y stage according to an embodiment of the present invention.

7 is a view for explaining an example of the driving mode of the X-Y stage for moving the sample in accordance with a temporary embodiment of the present invention.

8 is a view for explaining another example of the driving form of the X-Y stage for moving the sample in accordance with a temporary embodiment of the present invention.

FIG. 9 is a diagram for describing a pixel data type provided by dividing the entire data of one line of a sample according to one embodiment of the present invention.

10 is a flowchart illustrating a terahertz wave measurement process in the case of obtaining information about a point of a sample by driving an X-Y stage according to a temporary embodiment of the present invention.

Claims (7)

By using optical delay means including a rotating reflector having a plurality of wings, the laser beams separated by two paths in the beam splitter have a time difference, The laser beams having the time difference are incident to the terahertz wave generating means and the terahertz wave detecting means, respectively. When the trigger signal is generated from the means for controlling the optical delay means, in the activated DAQ system, a voltage signal corresponding to the current signal generated by the terahertz wave detection means is sampled to generate the terahertz wave generation means and the terahertz wave. A terahertz wave measurement system, characterized in that data of terahertz wave pulses are collected for a sample between detection means. The method of claim 1, wherein the terahertz wave measurement system, Terahertz wave, characterized in that the measurement is performed on a plurality of terahertz wave pulses proportional to the speed of rotating the rotatable reflector in response to the one trigger signal and the waveform scan frequency based on the number of the plurality of vanes. Measuring system. The method of claim 1, Preselected optical delay length resolution △ l, waveform scanning frequency f _s, and the measured pulse number n and the sampling rate of the DAQ system determined based on the SR, the rotating speed of the motor for rotating the screening reflector RPM, and the whole measurement data can Means for controlling the optical delay means in accordance with Ntot and a system controller for controlling the DAQ system The terahertz wave measurement system further comprises. The method of claim 1, And a stage controller for holding the sample and a stage controller for driving the stage. By driving the stage in the horizontal or vertical direction through the stage controller, And a terahertz wave measurement system for measuring a terahertz wave pulse by moving the horizontal spatial resolution with respect to the entire line of the sample divided by the vertical spatial resolution in response to the trigger signal. The method of claim 4, wherein the system controller, The preselected optical delay length resolution △ l, based on a waveform scan frequency f _s, the horizontal length l _x, the horizontal spatial resolution △ x, the vertical length l _y, the vertical spatial resolution △ y, the DAQ Sampling rate SR of the system, rotational speed RPM of the motor for rotating the rotary reflector, total number of measured data Ntot , horizontal velocity v _x , horizontal And means for controlling the optical delay means for the predetermined area of the sample and controlling the DAQ system by determining the total number of pixels n _x and n _y in the vertical direction. Separating the laser beam into two paths; Delaying any one of the laser beams such that the laser beams separated by the two paths have a time difference using optical delay means including a rotating reflector having a plurality of vanes; Injecting the laser beams having the time difference into the terahertz wave generating means and the terahertz wave detecting means, respectively; And When a trigger signal is generated from the means for controlling the optical delay means, a voltage signal corresponding to the current signal generated by the terahertz wave detection means is sampled to sample between the terahertz wave generation means and the terahertz wave detection means. Collecting data of terahertz wave pulses Terahertz wave measurement method comprising a. The method of claim 6, The stage for holding the sample is driven in a horizontal or vertical direction, and in response to the one trigger signal, a horizontal spatial resolution is moved by a horizontal spatial resolution with respect to a whole line of the sample divided by vertical spatial resolution. Steps to Perform Instrumentation for Terahertz wave measuring method further comprising a.

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