KR102357830B1 - Raman spectroscopy system using frequency-tunable diode laser according to pulse power and control method therefor - Google Patents

Abstract

The present invention relates to a Raman spectroscopy system using a frequency tunable diode laser according to pulse power and a control method thereof, and more particularly to the Raman spectroscopy system using a frequency-tunable diode laser according to pulse power and the control method thereof, comprising: a power supply part that supplies a pulse signal; a power amplifying part for amplifying the pulse signal; a Raman probe that generates a Raman scattered light by irradiating a frequency-tunable diode laser to the sample when the amplified pulse signal is input from the power amplifying part; and a Raman spectrometer that generates a Raman spectrum by spectroscopy of the Raman scattered light, and corrects the Raman spectrum whose phase is changed according to at least one of a duty ratio of the pulse signal or a power frequency, thereby capable of increasing the resolution of the sample to be analyzed and facilitating the analysis of chemical or biological reactions.

Description

Raman spectroscopy system using frequency-tunable diode laser according to pulse power and control method therefor

The present invention relates to a Raman spectroscopy system using a frequency tunable diode laser according to pulse power and a control method thereof, and more particularly, to a phase of a Raman spectrum changed according to at least one of a duty ratio of a pulse signal or a power frequency To a Raman spectroscopy system using a frequency-tunable diode laser according to pulse power, which can obtain a more accurate Raman signal by correcting the change, and a method for controlling the same.

The Raman spectroscopy technique is an analysis technique that irradiates a laser onto a target sample and discriminates the material components from the spectrum obtained therefrom. When a sample is irradiated with a laser, which is a monochromatic light source, light is scattered. Most of the scattered light is a signal corresponding to the wavelength of the laser, but some of the scattered light is a Raman shift (Raman shift) corresponding to the frequency of the vibration mode of the sample at the wavelength of the laser. ), there is a signal coming out.

By analyzing this signal, information on the shape and symmetry of molecules or crystals can be obtained, and the degree of crystallization of the sample can be determined. This change in wavelength appears differently depending on the structural properties of the material, and appears as a unique property for each specific material, so the Raman spectrum is called the fingerprint of the material.

However, the conventional Raman spectrometer is a very powerful tool for analyzing chemical substances, but since a fixed DC power supply is used as a laser power source in the spectrometer, the resolution of the spectrum is not high, or it is difficult to analyze a chemical or biological reaction to be analyzed.

In addition, in the case of a Raman spectrometer using a laser operating at a high frequency from nanoseconds to femtoseconds in the related art, a special power supply is required to obtain sufficient laser power, and it is difficult to analyze the range in microseconds.

In addition, a Raman spectrometer using an expensive laser can supply a constant power, but as it is expensive equipment, economical efficiency is low, and when a low-cost laser is used, the resolution of the Raman spectrometer for an electrical signal and the position of the Raman signal change.

Related Document 1 relates to a Raman spectrometer having a laser power regulator, and Related Document 2 relates to a non-invasive line-irradiation spatial displacement Raman spectrometer. The related documents 1 and 2 include a configuration for adjusting the laser output to prevent damage to the specimen and improve the Raman signal acquisition efficiency. The disadvantage is that it is difficult to perform a precise analysis.

KR 10-1965803 KR 10-1350402

The present invention is to solve the above problems, and to increase the resolution of the sample to be analyzed and to facilitate the analysis of a chemical reaction or a biological reaction, the frequency according to the pulse power using a frequency-tunable diode laser according to the pulse power An object of the present invention is to obtain a Raman spectroscopy system using a tunable diode laser and a method for controlling the same.

In addition, it is an object of the present invention to track the peak wavelength of the Raman spectrum so as to obtain an accurate Raman signal by correcting the phase change of the Raman spectrum that may be generated depending on the duty ratio of the power supply pulse signal or the power frequency, To provide a Raman spectroscopy system using a frequency tunable diode laser according to pulse power to obtain a final corrected spectrum by multiplying a correction factor by a wavenumber conversion using the peak wavelength, and a method for controlling the same.

In order to achieve the above object, a Raman spectroscopy system using a frequency tunable diode laser according to a pulse power supply of the present invention includes a power supply unit for supplying a pulse signal; a power amplifier for amplifying the pulse signal; a Raman probe for generating Raman scattered light by irradiating a frequency-tunable diode laser to a sample when the pulse signal amplified from the power amplifier is input; and a Raman spectrometer configured to generate a Raman spectrum by dividing the Raman scattered light, and correcting the Raman spectrum whose phase is changed according to at least one of a duty ratio of the pulse signal and a power frequency; provides

In order to achieve the above object, a control method of a Raman spectroscopy system using a frequency tunable diode laser according to a pulse power supply of the present invention includes: a pulse signal supply step to which a pulse signal is supplied; a pulse signal amplifying step in which the pulse signal is amplified; a Raman scattered light generating step of irradiating a frequency tunable diode laser to the sample and generating Raman scattered light when the pulse signal amplified from the pulse signal amplifying step is input; and a Raman spectrum generating step of generating a Raman spectrum for the Raman scattered light. a Raman spectrum correction step in which the phase-changed Raman spectrum is corrected according to at least one of a duty ratio of the pulse signal or a power frequency; provides

As described above, according to the present invention, by providing a frequency tunable diode laser according to pulse power, the resolution of a Raman signal generated from a sample to be analyzed is increased, and there is an effect of facilitating the analysis of a chemical reaction or a biological reaction. .

In addition, the present invention tracks the peak wavelength of the Raman spectrum, converts the wave number using the peak wavelength, and then multiplies it by a correction factor to finally obtain a corrected spectrum. There is an effect that a more accurate Raman signal can be obtained by correcting the phase change of the Raman spectrum that may be generated accordingly.

1 is a configuration diagram of a Raman spectroscopy system using a frequency tunable diode laser according to a pulse power supply of the present invention.
2 is an internal configuration diagram of a Raman probe according to an embodiment of the present invention.
3 is a flowchart of a control method of a Raman spectroscopy system using a frequency-tunable diode laser according to a pulse power source of the present invention.
4 is a detailed flowchart of the Raman spectrum correction step of the present invention.
5 is a view showing a Raman spectrum according to an embodiment of the present invention.
6 is a graph showing Raman spectra according to duty ratios for solid and liquid samples according to an embodiment of the present invention.
7 is a graph showing Raman spectra according to power frequency for solid and liquid samples according to an embodiment of the present invention.
8 is a graph for obtaining a correction factor according to a power frequency for a solid sample according to an embodiment of the present invention.
9 is a graph showing a calibration spectrum for a solid sample according to an embodiment of the present invention.

The terms used in this specification have been selected as currently widely used general terms as possible while considering the functions in the present invention, but these may vary depending on the intention or precedent of a person skilled in the art, the emergence of new technology, and the like. In addition, in a specific case, there is a term arbitrarily selected by the applicant, and in this case, the meaning will be described in detail in the description of the corresponding invention. Therefore, the term used in the present invention should be defined based on the meaning of the term and the overall content of the present invention, rather than the name of a simple term.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

Hereinafter, an embodiment according to the present invention will be described in detail with reference to the accompanying drawings. 1 is a configuration diagram of a Raman spectroscopy system using a frequency tunable diode laser according to a pulse power supply of the present invention.

Referring to FIG. 1 , a Raman spectroscopy system using a frequency tunable diode laser according to a pulse power of the present invention includes a power supply unit 100 , a power amplification unit 200 , a Raman probe 300 , and a Raman spectrometer 400 .

More specifically, the power supply unit 100 supplies a pulse signal.

The power supply unit 100 may be a function generator that may be used as a high frequency pulse power supply device, and may control a duty ratio or a power frequency of the pulse signal.

In addition, since the pulse signal is a square wave of a periodic waveform, a duty ratio that is a ratio of a conduction period to a period may be obtained. As the duty ratio of the pulse signal increases, the energy of the pulse signal increases.

Next, the power amplifier 200 amplifies the pulse signal. The power amplifier 200 can amplify a wide band from a very low frequency to a high frequency, and has an amplification circuit with good phase characteristics.

Next, when the pulse signal amplified from the power amplifier 200 is input, the Raman probe 300 irradiates a frequency-tunable laser to the sample to generate Raman scattered light.

2 is an internal configuration diagram of a Raman probe 300 according to an embodiment of the present invention.

2, in order to generate the Raman scattered light, the Raman probe 300 includes a laser diode 310, a convex lens 320, a reflective mirror 330, a sample holder 340, a concave lens 350, and a path. It may include an adjustment coil 360 , a Raman filter 370 , a condensing lens 380 , and an optical fiber 390 .

The laser diode 310 emits excitation light having a variable frequency according to the pulse signal supplied from the power supply unit 100 . That is, the laser diode 310 is not a pulse signal having a constant frequency, but is most preferably operable in a pulse signal having a broadband power frequency including 1 to 10 MHz. And the laser diode 310 becomes the light source of the frequency tunable laser.

The convex lens 320 allows the excitation light to converge to a focus of the convex lens 320 .

When the excitation light converged from the convex lens 320 is incident, the reflection mirror 330 reflects the excitation light at a reflection angle having the same magnitude as the incident angle.

The sample holder 340 fixes the sample at a corresponding position so that the excitation light reflected from the reflection mirror 330 is incident on the sample.

The concave lens 350 emits the excitation light reflected from the sample fixed to the sample holder 340 .

The path adjusting coil 360 is provided as a pair at the distal end of the concave lens 350 . In addition, the path adjustment coil 360 adjusts the path of the excitation light by moving the concave lens 350 up, down, left and right when power is applied. That is, the path adjustment coil 360 may generate a clear Raman signal by well incident the excitation light to the Raman filter 370 .

The Raman filter 370 generates the Raman scattered light by using the Raman effect when the path-adjusted excitation light is incident from the path adjustment coil 360 . Here, Raman scattering is a phenomenon in which, in general, when light of a constant frequency is irradiated to a material, light of a different frequency is scattered by the molecular natural vibration or rotational energy or the lattice vibration energy of the crystal.

The condensing lens 380 condenses the Raman scattered light.

The optical fiber 390 moves the focused Raman scattered light to the Raman spectrometer 400 .

That is, the Raman probe 300 is different from the conventional Raman probe in that it is a laser-integrated probe. Conventional Raman probes use an externally located laser in connection with an optical fiber. However, since the Raman probe 300 includes the laser diode 310 integrally, the light source does not shake and provides a constant excitation light path to enable clearer Raman analysis.

Next, the Raman spectrometer 400 generates a Raman spectrum by splitting the Raman scattered light, and corrects the Raman spectrum changed according to one of a duty ratio of the pulse signal or a power frequency.

In general, when a constant DC power source is used in a miniaturized Raman spectrometer, heat is severe and continuous cooling problem occurs, resulting in poor analysis accuracy. In order to solve this problem, in the present invention, by providing the power supply unit 100 for supplying the pulse signal, the Raman heat generation is small, the cooling problem can be solved, and a more precise Raman signal can be obtained.

However, it can be seen through the following experiment that the phase of the Raman spectrum is changed according to the duty ratio or the power frequency when the Raman spectrum is obtained using the pulse signal. Accordingly, the Raman spectrometer 400 may include a wavelength tracking unit 410 , a wavenumber conversion unit 420 , and a phase change correcting unit 430 to correct the Raman spectrum.

The wavelength tracking unit 410 tracks the peak wavelength of the frequency tunable laser from the Raman spectrum.

3nm 범위에서 상기 피크 파장을 추적할 수 있다.Most preferably, the wavelength tracking unit 410 may be a notch filter or a Raman edge, and at a preset peak wavelength of the frequency tunable laser

The peak wavelength can be traced in the 3 nm range.

Here, the notch filter generally refers to an optical device or an electric circuit that selectively attenuates only light or radio waves having a specific wavelength, and in the visible light region, only light within a certain range from the central wavelength is selectively about 1 in a million. It is an easy filter for easy measurement by removing strong light used in Raman spectroscopy because it can attenuate up to the following.

3nm 범위에서 상기 피크 파장을 추적할 수 있고, 상기 피크파장은 519.5nm, 520.1nm, 520.5nm 등일 수 있다. For example, if the preset wavelength of the frequency tunable laser is 520 nm, the wavelength tracking unit 410 uses 520 nm as a reference.

The peak wavelength may be tracked in a range of 3 nm, and the peak wavelength may be 519.5 nm, 520.1 nm, 520.5 nm, or the like.

Next, the wavenumber converter 420 may convert all wavelengths of the Raman spectrum into wavenumbers using the peak wavelength and then generate a wavenumber conversion spectrum. In this case, the wavenumber converter 420 converts all wavelengths of the Raman spectrum into wavenumbers by the following [Equation 1].

[Equation 1]

는 상기 파장 추적부(410)로부터 추적된 피크 파장이고, 상기

는 상기 라만 스펙트럼의 모든 파장이다.where W is the wavenumber,

is the peak wavelength tracked by the wavelength tracking unit 410,

is all wavelengths of the Raman spectrum.

는 상기 파장 추적부(410)로부터 추적된 피크 파장인 520.1nm가 대입될 수 있고, 상기

는 상기 라만 스펙트럼의 모든 파장이 대입될 수 있다. 이에 따라, 상기 파수 변환부(420)는 상기 라만 스펙트럼의 모든 파장을 파수로 변환한 후 파수변환 스펙트럼을 생성할 수 있다. 이는 최초에 얻은 라만 스펙트럼을 파수변환 스펙트럼으로 보정하는 1차 보정이라고 할 수 있다.For example, the

520.1 nm, which is the peak wavelength tracked by the wavelength tracking unit 410, may be substituted for

can be substituted for all wavelengths of the Raman spectrum. Accordingly, the wavenumber conversion unit 420 may convert all wavelengths of the Raman spectrum into wavenumbers and then generate a wavenumber conversion spectrum. This can be said to be a first-order correction that corrects the initially obtained Raman spectrum with a wavenumber conversion spectrum.

Next, the phase change correcting unit 430 obtains the wavenumber for the peak wavelength as a correction factor to correct the phase change of the wavenumber conversion spectrum, and multiplies each wavenumber in the wavenumber conversion spectrum by the correction factor to obtain a correction spectrum can create

Most preferably, the phase change correcting unit 430 may obtain a difference value of the wave number with respect to the difference value of the peak wavelength obtained according to a duty ratio of the pulse signal or a power frequency as the correction factor. have. That is, the correction factor may be a slope value of the graph.

Also, the phase change correcting unit 430 may obtain a corrected spectrum obtained by finally correcting a phase changed according to one of a duty ratio of the pulse signal or a power frequency. This can be said to be a secondary correction in which the wavenumber conversion spectrum is corrected with a correction spectrum after the primary correction.

Accordingly, in order to solve the problem of severe heat generation by continuously using a constant DC power in the prior art, the present invention can reduce the temperature change inside the frequency tunable laser by applying the pulse signal to the Raman probe 300 . there is

In addition, since the present invention uses the pulse signal, heat generation is low, so that a precise spectrum can be obtained without a cooling device for the frequency tunable laser. And since the present invention does not separately provide a cooling device, there is a remarkable effect that the Raman probe 300 can be integrally provided.

In addition, the present invention provides a more precise spectrum to analyze a sample despite using the pulse signal by correcting a duty ratio or power frequency factor that may affect the spectrum while using the pulse signal There is an effect that can be done.

3 is a flowchart of a control method of a Raman spectroscopy system using a frequency-tunable diode laser according to a pulse power source of the present invention. 4 is a detailed flowchart of the Raman spectrum correction step (S500) of the present invention.

First, referring to FIG. 3, the control method of the Raman spectroscopy system using a frequency tunable diode laser according to the pulse power of the present invention includes a pulse signal supply step (S100), a pulse signal amplification step (S200), a Raman scattered light generation step (S300), It includes a Raman spectrum generation step (S400) and a Raman spectrum correction step (S500).

In the pulse signal supply step ( S100 ), a pulse signal is supplied to the power amplifier 200 by the power supply unit 100 .

In addition, since the pulse signal is a square wave of a periodic waveform, a duty ratio that is a ratio of a conduction period to a period may be obtained. As the duty ratio of the pulse signal increases, the energy of the pulse signal increases.

In the pulse signal amplification step ( S200 ), the pulse signal is amplified by the power amplifier 200 . The pulse signal amplification step ( S200 ) may be a broadband amplification from a very low frequency to a high frequency.

In the Raman scattered light generating step (S300), when the pulse signal amplified from the power amplifying step (S200) is input by the Raman probe 300, a frequency-tunable diode laser is irradiated to the sample and Raman scattered light is generated.

In the Raman spectrum generating step ( S400 ), a Raman spectrum for the Raman scattered light is generated by the Raman spectrometer 400 .

5 is a view showing a Raman spectrum according to an embodiment of the present invention.

Referring to FIG. 5 , an actual peak wavelength, a Raman wavelength, and a fluorescence emission wavelength of the frequency tunable diode laser can be identified within the Raman spectrum graph indicating signal intensity versus wavelength.

Next, in the Raman spectrum correction step S500 , the Raman spectrum whose phase is changed according to at least one of a duty ratio of the pulse signal and a power frequency is corrected by the Raman spectrometer 400 .

That is, the initial Raman spectrum generated in the Raman spectral perm generation step S400 is a spectrum whose phase is changed according to a duty ratio of the pulse signal or a power frequency. In other words, a process of correcting this is absolutely necessary.

Referring to FIG. 4 , the Raman spectrum correction step S500 may include a wavelength tracking step S510 , a wavenumber conversion step S520 , and a phase change correction step S530 to correct the Raman spectrum.

In the wavelength tracking step ( S510 ), the peak wavelength of the frequency tunable diode laser is tracked from the Raman spectrum by the wavelength tracking unit 410 .

3nm 범위에서 상기 피크 파장을 추적할 수 있다.Most preferably, the wavelength tracking step (S510) is performed at a preset peak wavelength of the frequency tunable laser.

The peak wavelength can be traced in the 3 nm range.

3nm 범위에서 상기 피크 파장을 추적할 수 있고, 상기 피크파장은 519.5nm, 520.1nm, 520.5nm 등일 수 있다. For example, in the wavelength tracking step ( S510 ), if the preset wavelength of the tunable laser is 520 nm, based on 520 nm

The peak wavelength may be tracked in a range of 3 nm, and the peak wavelength may be 519.5 nm, 520.1 nm, 520.5 nm, or the like.

Next, in the wavenumber conversion step ( S520 ), the peak wavelength is used by the wavenumber conversion unit 420 , and all wavelengths of the Raman spectrum are converted to wavenumbers, and then a wavenumber conversion spectrum is generated. In the wavenumber conversion step (S520), most preferably, all wavelengths of the Raman spectrum are converted into wavenumbers by the following [Equation 1].

[Equation 1]

는 상기 파장 추적부(410)로부터 추적된 피크 파장이고, 상기

는 라만 스펙트럼의 모든 파장이다.where W is the wavenumber,

is the peak wavelength tracked by the wavelength tracking unit 410,

is all wavelengths in the Raman spectrum.

는 상기 파장 추적단계(S510)로부터 추적된 피크 파장인 520.1nm가 대입될 수 있고, 상기

는 상기 라만 스펙트럼의 모든 파장이 대입될 수 있다. 이에 따라, 상기 파수 변환단계(S520)는 상기 라만 스펙트럼의 모든 파장이 파수로 변환된 후 파수변환 스펙트럼이 생성될 수 있다. 이는 최초에 얻은 라만 스펙트럼이 파수변환 스펙트럼으로 보정되는 1차 보정이라고 할 수 있다.For example, the

520.1 nm, which is the peak wavelength tracked from the wavelength tracking step (S510), may be substituted for

can be substituted for all wavelengths of the Raman spectrum. Accordingly, in the wavenumber conversion step ( S520 ), all wavelengths of the Raman spectrum are converted into wavenumbers, and then a wavenumber conversion spectrum may be generated. This can be said to be a primary correction in which the initially obtained Raman spectrum is corrected with a wavenumber transformation spectrum.

Next, in the phase change correcting step (S530), the wave number for the peak wavelength is obtained as a correction factor so that the phase change of the wave number conversion spectrum is corrected by the position change correcting unit 430, and within the wave number conversion spectrum Each wavenumber is multiplied by the correction factor to generate a correction spectrum.

Here, FIG. 8 is a graph for obtaining a correction factor according to a power frequency for a solid sample according to an embodiment of the present invention.

일 수 있다.Referring to FIG. 8 , the present experiment targets atracene, which is a solid sample, and in the pulse signal supply step ( S100 ), a pulse signal having one of a power frequency of 0.05 kHz to 1000 kHz may be supplied. When the power frequency of the pulse signal supplied from the pulse signal supply step S100 is 0.05 kHz, the peak wavelength may be estimated to be 520.1 nm from the wavelength tracking step S510. And in the wavenumber conversion step (S520), the wavenumber can be obtained after the peak wavelength and the last wavelength in the Raman spectrum are substituted in [Equation 1], 3124.8

can be

일 수 있다.And when the power frequency of the pulse signal supplied from the pulse signal supply step S100 is 1000 kHz, the peak wavelength may be estimated to be 519.5 nm in the wavelength tracking step S510. And in the wavenumber conversion step (S520), the wavenumber can be obtained after the peak wavelength and the last wavelength in the Raman spectrum are substituted in [Equation 1], 3069

can be

/0.1nm가 보정인자로 얻어질 수 있다. 즉, 상기 보정인자는 도 8과 같이 그래프의 기울기 값일 수 있다. At this time, in the phase change correction step (S530), when the power frequency is 0.05 kHz and 1000 kHz, respectively, the difference value of the wave number with respect to the difference value of the peak wavelength is 9.3

/0.1 nm can be obtained as a correction factor. That is, the correction factor may be a slope value of the graph as shown in FIG. 8 .

In the phase change correction step ( S530 ), each wavenumber in the wavenumber conversion spectrum is multiplied by the correction factor to generate a correction spectrum.

That is, the phase change correction step ( S530 ) may be referred to as secondary correction in which the wavenumber conversion spectrum is corrected to the correction spectrum after the primary correction.

9 is a graph showing a calibration spectrum for a solid sample according to an embodiment of the present invention. Accordingly, in the phase change correcting step (S530), as shown in FIG. 9 , a corrected spectrum in which a phase changed according to one of a duty ratio of the pulse signal or a power frequency is finally corrected can be obtained.

Hereinafter, it is checked whether a phase change occurs in the Raman spectrum according to one or more of a duty ratio of the pulse signal or a power frequency. Accordingly, the justification that appropriate correction is required for the Raman spectrum first obtained from the Raman spectrometer 400 will be explained.

Example 1

Experimental program and method

In order to analyze the effect of the duty ratio on the Raman spectrum, the power frequency of the pulse signal is fixed to 100 kHz, and the duty ratio is changed to 2 to 40% to obtain a Raman spectrum.

For the sample, liquid benzene (99.5%) and solid anthracene (97%) were used. In addition, the operating voltage of the power supply unit 100 was set to 8V in the case of liquid benzene and 7.4V in the case of solid anthracene, and it was confirmed that the saturation problem due to fluorescence emission existed at 8V.

Experiment result

6 is a graph showing Raman spectra according to duty ratios for solid and liquid samples according to an embodiment of the present invention. Referring to FIG. 6 (a), in the case of solid anthracene, it can be seen that the intensity of both the fluorescence emission signal and the Raman signal increased as the duty ratio of the pulse signal increased from 2% to 40%, It can be seen that the ratio of the Raman signal intensity to the fluorescence emission signal intensity also increased.

FIG. 6(b) is a Raman spectrum obtained after adjusting the baseline by normalization based on the 1403 wavenumber, which is the main peak of the solid anthracene, using a symmetric breathing vibration mode. Accordingly, in the case of the solid anthracene, it can be seen that the Raman signal increases as the duty ratio of the pulse signal increases.

However, in this experiment, when the duty ratio of the pulse signal increased to 25% or more, the Raman spectrum saturation was confirmed. In general, when Raman spectral saturation occurs, a Raman signal can be detected, but as the saturation range increases, the range over which the Raman signal can be analyzed decreases, making accurate analysis difficult. Accordingly, from the following experiment, the duty ratio of the pulse signal will be tested within the range of 2% to 20%.

Next, referring to FIG. 6C , in the case of the liquid benzene, it can be seen that both the fluorescence emission signal and the Raman signal increase as the duty ratio of the pulse signal increases from 2% to 20%, , it can be seen that the ratio of the Raman signal intensity to the fluorescence emission signal intensity also increases.

FIG. 6( d ) is a Raman spectrum obtained after adjusting the baseline by normalization based on the 992 wavenumber, which is the main peak of the liquid benzene, using the ring-stretching mode. Accordingly, in the case of the liquid benzene, it can be seen that the Raman signal increases as the duty ratio of the pulse signal increases.

Overall, in the experiments using the solid anthracene and liquid benzene as samples, the effect of the duty ratio on the Raman spectrum is that the Raman signal also increases as the duty ratio increases in a certain range. it is proven Most preferably, the duty ratio may be controlled within a range of 2 to 20% by the power supply unit 100 .

Example 2

Experimental conditions and methods

In order to analyze the effect of the power frequency on the Raman spectrum, the duty ratio of the pulse signal is fixed at 20%, and the power frequency is changed to 0.05 kHz-1MHz to obtain a Raman spectrum. Then, a Raman spectrum is obtained by averaging three spectra at an integration time of 20,000 ms.

For the sample, liquid benzene (99.5%) and solid anthracene (97%) were used. In addition, the operating voltage of the power supply unit 100 was set to 8V in the case of liquid benzene and 7.4V in the case of solid anthracene, and it was confirmed that the saturation problem due to fluorescence emission existed at 8V.

Experiment result

7 is a graph showing Raman spectra according to power frequency for solid and liquid samples according to an embodiment of the present invention. Referring to FIG. 7A , in the case of solid anthracene, the intensity of the Raman peak signal decreases as the power frequency increases from 0.05 kHz to 1 MHz.

7 (b) is a Raman spectrum obtained after adjusting the baseline by normalization based on the 1403 wavenumber, which is the main peak of the solid anthracene, using a symmetric breathing vibration mode. In the case of solid anthracene, it can be seen that the ratio of the Raman peak signal intensity to the fluorescence emission signal intensity also decreases as the power frequency increases from 0.05 kHz to 1 MHz.

However, referring to (c) of FIG. 7 , in the case of liquid benzene, the intensity of the Raman peak signal does not show a constant increase or decrease trend as the power frequency increases from 0.05 kHz to 1 MHz, but shows various changes.

Referring to (d) of FIG. 7, when the power frequency is 100 kHz or less, the ratio of the Raman peak signal to the fluorescence emission signal increases, and when it exceeds 100 kHz, it can be seen that the ratio of the Raman peak signal to the fluorescence emission signal decreases again. .

This is because the ratio of the Raman peak signal to the fluorescence emission signal of the liquid benzene is affected by the Raman scattering lifetime and fluorescence emission compared to the solid anthracene, and thus fluorescence emission is effectively suppressed as the power frequency increases.

Overall, in the experiments using the solid anthracene and liquid benzene as samples, the effect of the power frequency on the Raman spectrum is that the Raman signal decreases as the power frequency increases in a certain range. Most preferably, the power frequency may be controlled within the range of 0.05 kHz to 100 kHz by the power supply unit 100 .

According to the first and second embodiments, since the laser diode 310 in the Raman probe 300 operates on a DC power supply, theoretically light emitted from the laser diode 310 due to the voltage and current of the power supply unit 100 . Although there is no change in the wavelength of , it is verified that the phase change of the Raman spectrum occurs substantially according to at least one of a duty ratio of the pulse signal or a power frequency.

In addition, when the Raman spectrometer 400 corrects the Raman spectrum, it may be advantageous to increase the accuracy of the Raman spectrum by lowering the duty ratio and increasing the power frequency. Among them, increasing the power supply frequency within a certain range is more effective in increasing the accuracy of the Raman spectrum than decreasing the duty ratio.

In addition, the liquid sample is more sensitive to a change in the duty ratio of the pulse signal or the power supply frequency than the solid sample.

As described above, although the embodiments have been described with reference to the limited embodiments and drawings, various modifications and variations are possible from the above description by those skilled in the art. For example, the described techniques are performed in an order different from the described method, and/or the described components of the system, structure, apparatus, circuit, etc. are combined or combined in a different form than the described method, or other components Or substituted or substituted by equivalents may achieve an appropriate result.

Therefore, other implementations, other embodiments, and equivalents to the claims are also within the scope of the following claims.

100.. power supply
200.. Power Amplifier
300.. Raman probe
310.. Laser Diode
320. convex lens
330. Reflective Mirror
340. sample holder
350.. concave lens
360.. Routing Coil
370. Raman filter
380.. condensing lens
390. Fiber Optic
400.. Raman Spectrometer
410.. Wavelength Tracker
420. Wavenumber conversion part
430. Phase change correction unit

Claims (7)

a power supply unit for supplying a pulse signal;
a power amplifier for amplifying the pulse signal;
a Raman probe for generating Raman scattered light by irradiating a frequency-tunable diode laser to the sample when the amplified pulse signal is input from the power amplifier; and
a Raman spectrometer that generates a Raman spectrum by spectroscopy of the Raman scattered light, and corrects the Raman spectrum whose phase is changed according to at least one of a duty ratio of the pulse signal and a power frequency; including,
The Raman spectrometer is
a wavelength tracking unit for tracking a peak wavelength of the frequency tunable diode laser from the Raman spectrum;
a wavenumber converter for converting a wavelength of the Raman spectrum to a wavenumber using the peak wavelength and then generating a wavenumber conversion spectrum; and
a phase change correcting unit for obtaining a wavenumber for the peak wavelength as a correction factor to correct a phase change of the wavenumber conversion spectrum, and generating a correction spectrum by multiplying each wavenumber in the wavenumber conversion spectrum by the correction factor; Raman spectroscopy system using a frequency-tunable diode laser according to the pulse power comprising a. delete The method of claim 1,
The wavenumber conversion unit,
Raman spectroscopy system using a frequency tunable diode laser according to pulse power, characterized in that the wavelength of the Raman spectrum is converted into a wave number by the following [Equation 1].
[Equation 1]

where W is the wavenumber,

is the peak wavelength tracked from the wavelength tracking unit, and

is the wavelength of the Raman spectrum. The method of claim 1,
The Raman probe is
a laser diode that emits excitation light having a variable frequency according to the pulse signal;
a convex lens for converging the excitation light to a focal point;
a reflective mirror that reflects the excitation light converged from the convex lens at a reflection angle having the same magnitude as the incident angle;
a sample holder for fixing the sample so that the excitation light reflected from the reflection mirror is incident on the sample;
a concave lens emitting the excitation light reflected from the sample fixed to the sample holder;
a path adjusting coil provided as a pair at the distal end of the concave lens and adjusting the path of the excitation light by moving the concave lens up, down, left and right;
a Raman filter for generating the Raman scattered light using a Raman effect when the excitation light whose path has been adjusted is incident from the path adjustment coil;
a condensing lens for condensing the Raman scattered light; and
A Raman spectroscopy system using a frequency tunable diode laser according to a pulsed power supply comprising a; optical fiber for moving the focused Raman scattered light to the Raman spectrometer. a pulse signal supply step in which a pulse signal is supplied by the power supply unit;
a pulse signal amplifying step in which the pulse signal is amplified by a power amplifier;
a Raman scattered light generating step of irradiating a frequency-tunable diode laser to a sample and generating Raman scattered light when the pulse signal amplified from the pulse signal amplifying step is input by the Raman probe; and
a Raman spectrum generating step of generating a Raman spectrum for the Raman scattered light by a Raman spectrometer;
a Raman spectrum correction step of correcting, by the Raman spectrometer, the Raman spectrum whose phase is changed according to one or more of a duty ratio of the pulse signal or a power frequency; including,
The Raman spectrum correction step is
a wavelength tracking step in which a peak wavelength of the frequency tunable diode laser is tracked from the Raman spectrum by a wavelength tracking unit;
a wavenumber conversion step of generating a wavenumber conversion spectrum after the peak wavelength is used by the wavenumber conversion unit to convert the wavelength of the Raman spectrum to a wavenumber; and
By the phase change compensator, the wave number for the peak wavelength is obtained as a correction factor so that the phase change of the wave number conversion spectrum is corrected, and a correction spectrum is generated by multiplying each wave number in the wave number conversion spectrum by the correction factor phase change correction step; A control method of a Raman spectroscopy system using a frequency-tunable diode laser according to pulse power, comprising: delete 6. The method of claim 5,
The wavenumber conversion step is
A control method of a Raman spectroscopy system using a frequency tunable diode laser according to pulse power, characterized in that the wavelength of the Raman spectrum is converted to a wavenumber by the following [Equation 1].
[Equation 1]

where W is the wavenumber,

is the peak wavelength tracked from the wavelength tracking unit, and

is the wavelength of the Raman spectrum.

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