CN104655595A - Analysis system and analysis method of laser induced breakdown spectroscopy - Google Patents

Abstract

The invention provides an analysis system and an analysis method of two-dimensional energy associated laser induced breakdown spectroscopy. The analysis system comprises a laser, a spectrograph, a delay generator, an optical fiber, a sample and a computer, wherein the laser is used for periodically transmitting pulse laser to strike the sample; the delay generator is respectively connected with the laser and the spectrograph and used for triggering a spectrograph acquisition signal according to a preset delay time; the spectrograph is respectively connected with the optical fiber and the computer and used for acquiring a plasma optical signal transmitted by the sample by virtue of the optical fiber. According to the analysis system and the analysis method of the two-dimensional energy associated laser induced breakdown spectroscopy, the conventional laser induced breakdown spectroscopy is carried out on a laser energy scale, so that the spectral signature can be clearly analyzed, and the detection capability and the repeatability of the conventional laser induced breakdown spectroscopy method can be improved.

Description

The analytic system of Laser-induced Breakdown Spectroscopy and method

Technical field

The present invention relates to technical field of analytical chemistry, particularly relate to a kind of analytic system and method for Laser-induced Breakdown Spectroscopy.

Background technology

Laser-induced Breakdown Spectroscopy is a kind of novel spectrographic detection means, and its principle utilizes strong laser irradiation sample, makes it be excited to plasma state, then collects the emission spectrum of plasma state with spectrometer, thus the constituent content in analyzing samples.In recent years, the trace element that LIBS is applied in iron and steel, coal dust, mural painting, soil, timber equal samples is measured.

At present, because Laser-induced Breakdown Spectroscopy needs laser to puncture to obtain plasma state spectrum to sample in the measurements, under the impact of the problem such as energy of lasers shake, sample surface unevenness, plasma plume diffusion instability, the stability that Laser-induced Breakdown Spectroscopy is measured is very poor, causes an a lot of difficult problem in quantification metering.Existing in the measurement of Laser-induced Breakdown Spectroscopy, have employed a lot of method improving stability and repeatability.Average as repetitive measurement or utilize plasma state parameter to revise spectrum.

But these methods can improve measuring repeatability, but it is not high to improve degree.In addition, another problem of Laser-induced Breakdown Spectroscopy is that its detectability is not high, and on the one hand, some more weak element energy jump spectral lines are not easily identified, and on the other hand, some spectral lines are narrower, are easy to, together with other overlaps of spectral lines, cause identification error.

Summary of the invention

The present invention is directed to the deficiencies in the prior art, propose a kind of analytical approach and system of Laser-induced Breakdown Spectroscopy, more clearly can resolve spectral signature, improve detectability and the repeatability of conventional laser-induced breakdown spectral method.

First aspect, the invention provides a kind of analytic system of two-dimentional energy associated laser induced breakdown spectroscopy, comprising: laser instrument, spectrometer, delay time generator, optical fiber, sample and computing machine; Described laser instrument, impacts described sample for periodically emission pulse laser; Described delay time generator is connected with described laser instrument and described spectrometer respectively, for according to the delay time preset, triggers described spectrometer collection signal; Described spectrometer is connected with described computing machine with described optical fiber respectively, for being collected the plasma light signal that described sample sends by optical fiber.

Preferably, described delay time generator is the picosecond accurate delay system adopting FPGA to control.

Preferably, described system also comprises: converging device, described converging device and described Fiber connection, for converging the plasma light signal that described sample sends, and is delivered to described spectrometer through optical fiber.

Preferably, described converging device is the card Sa Gelin system being placed in described optical fiber front end.

Preferably, described system also comprises: beam splitter, and described beam splitter is placed in described laser emitting position, for described laser instrument is launched 10% pulsed laser energy reflex to photodiode.

Second aspect, the invention provides a kind of analytical approach of two-dimentional energy associated laser induced breakdown spectroscopy, comprising:

Spectrometer is measured the dark background not placing sample, obtains background spectrum, and deducts interference and this bulk noise of described background spectrum;

Under energy perturbation state, carrying out spectral measurement, by increasing the laser energy that laser instrument is launched, obtaining described sample one dimension spectrum under breakdown conditions;

Obtain the exact numerical of laser energy, according to described exact numerical, laser power calibration and normalized are carried out to described one dimension spectrum;

Calculate two-dimensional correlation spectra according to one dimension spectrum, described two-dimensional correlation spectra comprises: synchronous correlation spectrum and asynchronous correlation spectrum;

Be separated the self correlated peak in two-dimensional correlation spectra, intersection peak, and corresponding with one dimension spectrum.

Preferably, the exact numerical of described acquisition laser energy, carries out laser power calibration and normalized according to described exact numerical to described one dimension spectrum, comprising:

Photodiode receives the laser energy of beam splitter feedback, and measures laser energy in real time;

According to deviate, corresponding coefficient is multiplied by original spectrum, and compensates the deviation of described laser energy;

Be spectroscopic data described in window record with 50nm, carry out area normalization in each described window.

Preferably, describedly under energy perturbation state, carry out spectral measurement, by increasing the laser energy that laser instrument is launched, obtaining described sample one dimension spectrum under breakdown conditions, comprising:

When impacting first, described laser instrument take basal energy as 100-200mJ, and frequency is that the laser pulse of 10HZ impacts described sample;

After impact first, the basal energy impact sample of each increase by 5%, to obtain the spectroscopic data of gradual change.

Preferably, the described synchronous correlation spectrum calculated according to one dimension spectrum in two-dimensional correlation spectra, comprising:

Described synchronous correlation spectrum is calculated according to formula one:

${\mathrm{\Φ}}_1=\frac{1}{S_{\max }-S_{\min }}\underset{j=1}{\mathrm{\Σ}}[y_j\left({\mathrm{\υ}}_1\right)\·y_j\left({\mathrm{\υ}}_2\right)]$ Formula one

Wherein, S _maxfor the spectral intensity maximal value of described spectrometer collection, S _minfor the spectral intensity minimum value of described spectrometer collection, y _j(υ ₁) and y _j(υ ₂) be the spectra values of different-waveband.

Preferably, the described asynchronous correlation spectrum calculated according to one dimension spectrum in two-dimensional correlation spectra, comprising:

Described asynchronous correlation spectrum is calculated according to formula two:

${\mathrm{\Φ}}_2=\frac{1}{S_{\max }-S_{\min }}\underset{j=1}{\mathrm{\Σ}}\left\{y_j\left({\mathrm{\υ}}_1\right)\underset{k=1}{\mathrm{\Σ}}{y}_k\left({\mathrm{\υ}}_2\right)\right\}$ Formula two

Wherein, S _maxfor the spectral intensity maximal value of described spectrometer collection, S _minfor the spectral intensity minimum value of described spectrometer collection, y _j(υ ₁) and yk (υ ₂) be the spectra values of different-waveband.

The invention provides a kind of analytic system and method for Laser-induced Breakdown Spectroscopy of being correlated with based on two-dimentional energy, the two-dimensional correlation spectra of the Laser-induced Breakdown Spectroscopy being disturbance can be obtained with laser energy, relative to one dimension spectrum, quantitative and qualitative analysis can be realized more accurately and measure.Different peak value can be disclosed, peak position with the variation relation of laser energy, thus realizes strengthening and the feature extraction of some weak peak-to-peak signals, more clearly can resolve spectral signature, improve detectability and the repeatability of conventional laser-induced breakdown spectral method.

Accompanying drawing explanation

In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, be briefly described to the accompanying drawing used required in embodiment or description of the prior art below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these accompanying drawings.

The structural representation of the analytic system of the two-dimentional energy associated laser induced breakdown spectroscopy that Fig. 1 provides for the embodiment of the present invention;

The schematic flow sheet of the analytical approach of the two-dimentional energy associated laser induced breakdown spectroscopy that Fig. 2 provides for the embodiment of the present invention;

The part run schematic diagram of the analytical approach of the two-dimentional energy associated laser induced breakdown spectroscopy that Fig. 3 provides for the embodiment of the present invention;

The main-process stream schematic diagram of the analytical approach of the two-dimentional energy associated laser induced breakdown spectroscopy that Fig. 4 provides for the embodiment of the present invention.

Reference numeral:

1, laser instrument; 2, spectrometer; 3, delay time generator; 4, optical fiber; 5, sample; 6, computing machine.

Embodiment

Below in conjunction with the accompanying drawing in the embodiment of the present invention; technical scheme in the embodiment of the present invention is clearly and completely described; obviously; described embodiment is only the present invention's part embodiment; instead of whole embodiments; based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtained under creative work prerequisite, belong to the scope of protection of the invention.

Fig. 1 shows the analytic system of the two-dimentional energy associated laser induced breakdown spectroscopy that the embodiment of the present invention provides, as shown in Figure 1, the analytic system of the two-dimentional energy associated laser induced breakdown spectroscopy of the present embodiment, comprising: laser instrument 1, spectrometer 2, delay time generator 3, optical fiber 4, sample 5 and computing machine 6; Wherein, delay time generator 3 is connected with laser instrument 1 and spectrometer 2 respectively, spectrometer 2 respectively with optical fiber 4 with calculate 6 machines and be connected,

In the present embodiment, laser instrument 1 is for periodically emission pulse laser and impact sample 5, sample 5 can be iron and steel, coal dust, mural painting, soil or timber etc., the pulse energy of laser instrument 1 is 100-200mJ, beating frequency is 10hz, preferably, the basal energy that laser instrument 1 impacts sample is first 150mJ, after this, laser instrument increases by 5% energy at every turn steadily, order impact sample 5, the delay time that delay time generator 2 is preset for basis, spectrometer 2 collection signal is triggered, wherein, the delay time of each triggering is all consistent with first time, due to first continuous spectrum can be shown as after laser breakdown sample 5, therefore the picosecond accurate delay system that the delay time generator 3 in the present embodiment adopts FPGA to control, and spectrometer 2 collection signal is triggered, to guarantee to obtain the strict spectroscopic data of sequential.

It should be noted that the delay time preset in the present embodiment is 2 μ s, but be not only limited to 2 μ s, in practice, can sets itself as required.

Further, the plasma light signal that the spectrometer 2 in the present embodiment is sent for being collected sample 5 by optical fiber 4, before measurement sample 5, spectrometer 2 should first background correction interference and this bulk noise, thus to obtain will be spectral information accurately.Therefore, with spectrometer 2, the dark background not placing sample 5 is measured, obtain background spectrum, with it for demarcating foundation.

In another embodiment, described system also comprises not shown converging device, converging device is connected with optical fiber 4, for converging the plasma light signal that sample 5 sends, and be delivered to spectrometer 2 through optical fiber 4, alternatively, converging device is the card Sa Gelin system being arranged at described optical fiber 4 front end, thus can obtain high-throughout optical signalling.

In the present embodiment, inevitably there is the problems such as energy shake due to laser instrument 1, the correlation analysis of spectrum can be had influence on.Therefore, the present embodiment also comprises not shown beam splitter, and beam splitter is placed in laser instrument 1 exit position, and the laser part after beam splitter beam splitting is for impacting sample, and a part is used for feedback

For example, beam splitter can 45° angle incident, adopt 10:90 spectroscope, the pulse laser that laser instrument 1 sends is in strict accordance with 10:90 transmission 90% luminous energy, reflect 10% luminous energy, when the basal energy that laser instrument 1 sends is 150mJ, energy of reflection light is 15mJ, energy of reflection light is that 15mJ enters Energy detection block, Energy detection block can be accurately detected the energy that beam splitter branches away luminous energy and light pulse 1/10th, preferably, Energy detection block in the present embodiment is the photodiode being arranged on feedback laser bundle position, photodiode can measure laser energy in real time, thus spectral intensity is revised.

Particularly, photodiode is measured the pulsed laser energy of 10% and is passed to computing machine 6 as normalization standard value using logical for energy value, the spectrum that laser induced plasma gives off is collected by optical fiber 4, be coupled in spectrometer 2 by optical fiber 4, spectral analysis data passes to computing machine 6 by interface circuit.

In a particular application, spectroscopic data, after acquisition, needs to carry out pre-service to it, the erratic behavior problem caused with the noise eliminated in measuring process.First, laser energy deviation is compensated, according to deviate, corresponding coefficient is multiplied by original spectrum.Secondly, institute's spectra re-recorded data take 50nm as window, carry out area normalization in each window.Namely within the scope of every 50nm, the area of spectroscopic data is classified as 1, after this, the self correlated peak in two-dimensional correlation spectra and intersection peak can be separated.Self correlated peak and intersection peak indicate the Changing Pattern that each spectral signature increases along with laser energy.In conjunction with the characteristic peak positions of original spectrum, obtain the correlativity of each spectral signature change, and then be separated comparatively close overlap peak, and fainter spectrum peak.

The present embodiment can obtain with laser energy the two-dimensional correlation spectra of the Laser-induced Breakdown Spectroscopy being disturbance.Relative to one dimension spectrum, quantitative and qualitative analysis can be realized more accurately and measure.Different peak value can be disclosed, peak position with the variation relation of laser energy, thus realizes strengthening and the feature extraction of some weak peak-to-peak signals.

Fig. 2 shows the schematic flow sheet of the two-dimentional energy associated laser induced breakdown spectroscopy analytical approach that the embodiment of the present invention provides, and as shown in Figure 2, the two-dimentional energy associated laser induced breakdown spectroscopy analytical approach of the present embodiment is as described below.

201, spectrometer is measured the dark background not placing sample, obtains background spectrum, and deducts interference and this bulk noise of described background spectrum.

In the present embodiment, gather the background of spectrometer, and deduct baseline and dark current impact, to obtain stable spectral response data.Particularly, before measurement sample, in order to obtain spectral information more accurately, first spectrometer should background correction disturb and this bulk noise, therefore, first measures the dark background not placing sample with spectrometer, obtain background spectrum, and with it for demarcating foundation.

202, under energy perturbation state, carrying out spectral measurement, by increasing the laser energy that laser instrument is launched, obtaining described sample one dimension spectrum under breakdown conditions.

For example, laser instrument adopts basal energy to be 100-200mJ, and frequency is that the laser beam of 10hz impacts sample, more each 5% energy that increases steadily punctures sample, obtains the spectroscopic data of gradual change.Namely by increasing laser energy steadily, sample one dimension spectrum is under breakdown conditions obtained, to carry out the spectral measurement under energy perturbation state.

203, obtain the exact numerical of laser energy, according to described exact numerical, laser power calibration and normalized are carried out to described one dimension spectrum.

In the present embodiment, the method adopting feedback to measure obtains the exact numerical of laser energy, and adopts the methods such as multiwindow area normalization to improve Measurement sensibility and the repeatability of spectrum, makes it can be used for two-dimensional correlation spectra and calculates.

204, calculate two-dimensional correlation spectra according to described one dimension spectrum, described two-dimensional correlation spectra comprises: synchronous correlation spectrum and asynchronous correlation spectrum.

205, the self correlated peak in two-dimensional correlation spectra, intersection peak is separated, and corresponding with one dimension spectrum.

It should be noted that self correlated peak and intersect peak and indicate the Changing Pattern that each spectral signature increases along with laser energy.In conjunction with the characteristic peak positions of original spectrum, obtain the correlativity of each spectral signature change, and then comparatively close overlap peak can be separated, and fainter spectrum peak.

In step 204, described synchronous correlation spectrum is calculated according to formula one:

${\mathrm{\Φ}}_1=\frac{1}{S_{\max }-S_{\min }}\underset{j=1}{\mathrm{\Σ}}[y_j\left({\mathrm{\υ}}_1\right)\·y_j\left({\mathrm{\υ}}_2\right)]$ Formula one

Wherein, S _maxfor the spectral intensity maximal value of described spectrometer collection, S _minfor the spectral intensity minimum value of described spectrometer collection, y _j(υ ₁) and y _j(υ ₂) be the spectra values of different-waveband.

Described asynchronous correlation spectrum is calculated according to formula two:

${\mathrm{\Φ}}_2=\frac{1}{S_{\max }-S_{\min }}\underset{j=1}{\mathrm{\Σ}}\left\{y_j\left({\mathrm{\υ}}_1\right)\underset{k=1}{\mathrm{\Σ}}{y}_k\left({\mathrm{\υ}}_2\right)\right\}$ Formula two

Wherein, S _maxfor the spectral intensity maximal value of described spectrometer collection, S _minfor the spectral intensity minimum value of described spectrometer collection, y _j(υ ₁) and yk (υ ₂) be the spectra values of different-waveband.

It is the two-dimensional laser induced breakdown spectroscopy of disturbance that the method for the present embodiment can obtain with energy of lasers, realizes the expansion of conventional laser-induced breakdown spectral at energy scale.On the one hand, the impact of laser instrument shake on spectral measurement repeatability is effectively eliminated; On the other hand, by the identification of auto-correlation information some weak peak and overlap peaks of spectral line, the detectability of Laser-induced Breakdown Spectroscopy can be improved.

Fig. 3 shows the part run schematic diagram of the two-dimentional energy associated laser induced breakdown spectroscopy analytical approach that the embodiment of the present invention provides, and particularly, Fig. 3 shows the schematic flow sheet of step 203 in Fig. 2, and as shown in Figure 3, step 203 specifically comprises:

2031, photodiode receives the laser energy of beam splitter feedback, and measures laser energy in real time.

In the present embodiment, beam splitter reflection 10% luminous energy, energy of reflection light enters photodiode, and photodiode can be accurately detected beam splitter and branch away luminous energy, and can measure laser energy in real time, thus revises spectral intensity.

2032, according to deviate, corresponding coefficient is multiplied by original spectrum, and compensates the deviation of described laser energy.

For example, spectroscopic data, after acquisition, needs to carry out pre-service to it, the erratic behavior problem caused with the noise eliminated in measuring process.First, laser energy deviation is compensated, according to deviate, corresponding coefficient is multiplied by original spectrum.

2033, take 50nm as spectroscopic data described in window record, carry out area normalization in each described window.

Be understandable that, namely within the scope of every 50nm, the area of spectroscopic data be classified as 1.

The present embodiment adopts the laser of graded energy to puncture sample, again the plasma spectrometry puncturing acquisition is processed, with the laser energy of gradual change for disturbance, calculate two-dimensional correlation laser spectrum, to obtain the Laser-induced Breakdown Spectroscopy launched at energy dimension.

Fig. 4 shows the schematic flow sheet of the two-dimentional energy associated laser induced breakdown spectroscopy analytical approach that the embodiment of the present invention provides, and as shown in Figure 4, the two-dimentional energy associated laser induced breakdown spectroscopy analytical approach of the present embodiment is as described below.

401, spectrometer background spectrum gathers, and spectrum dark background is deducted.

In the present embodiment, by gathering the background of spectrometer, deduction baseline and dark current impact, to obtain stable spectral response data.

402, laser instrument is set and punctures sample with basal energy, spectra re-recorded data.

Illustrate, laser instrument punctures sample with the basal energy of 100-200mJ first.

403, laser instrument increases by 5% energy at every turn steadily, punctures sample, spectra re-recorded data.

Be understandable that, by increasing laser energy steadily, obtain the one dimension spectrum of sample breakdown conditions under laser energy situation of change, the spectral measurement under energy perturbation state can be carried out.

404, the method by installing photodiode after beam splitter obtains accurate laser energy.

It should be noted that unavoidably there is the problems such as energy shake due to laser instrument, the correlation analysis of spectrum can be had influence on.Therefore, the present invention installs beam splitter in laser emitting position, and the laser part after beam splitting is used for feedback, installs photodiode in feedback laser bundle position.Diode measures laser energy in real time, thus revises spectral intensity.

405, institute's spectra re-recorded data take 50nm as window, carry out area normalization in each window.

In the present embodiment, laser energy deviation is compensated, namely according to deviate, corresponding coefficient is multiplied by original spectrum.Secondly, institute's spectra re-recorded data take 50nm as window, carry out area normalization in each window.Namely within the scope of every 50nm, the area of spectroscopic data is classified as 1, the erratic behavior problem caused with the noise eliminated in measuring process.

406, the synchronous correlation spectrum of two dimension is calculated.

In the present embodiment, calculate described synchronous correlation spectrum according to formula one:

${\mathrm{\Φ}}_1=\frac{1}{S_{\max }-S_{\min }}\underset{j=1}{\mathrm{\Σ}}[y_j\left({\mathrm{\υ}}_1\right)\·y_j\left({\mathrm{\υ}}_2\right)]$ Formula one

Wherein, S _maxfor the spectral intensity maximal value of described spectrometer collection, S _minfor the spectral intensity minimum value of described spectrometer collection, y _j(υ ₁) and y _j(υ ₂) be the spectra values of different-waveband.

407, two-dimentional asynchronous correlation spectrum is calculated.

In the present embodiment, calculate described asynchronous correlation spectrum according to formula two:

${\mathrm{\Φ}}_2=\frac{1}{S_{\max }-S_{\min }}\underset{j=1}{\mathrm{\Σ}}\left\{y_j\left({\mathrm{\υ}}_1\right)\underset{k=1}{\mathrm{\Σ}}{y}_k\left({\mathrm{\υ}}_2\right)\right\}$ Formula two

Wherein, S _maxfor the spectral intensity maximal value of described spectrometer collection, S _minfor the spectral intensity minimum value of described spectrometer collection, y _j(υ ₁) and yk (υ ₂) be the spectra values of different-waveband.

408, the self correlated peak in two-dimensional correlation spectra, intersection peak is separated, and corresponding with one dimension spectrum.

It should be noted that self correlated peak and intersect peak and indicate the Changing Pattern that each spectral signature increases along with laser energy.In conjunction with the characteristic peak positions of original spectrum, obtain the correlativity of each spectral signature change, and then comparatively close overlap peak and fainter spectrum peak can be separated.

It should be noted that the analytic system of the two-dimentional energy associated laser induced breakdown spectroscopy in the embodiment of the present invention can perform the whole flow processs in Fig. 2 to Fig. 4 method, no longer describe in detail herein.

The method of the present embodiment can be used for Laser-induced Breakdown Spectroscopy and measures, as coal dust medium trace element content measurement, Steel Elements purity determination, aerocolloidal composition measurement etc., cut down energy of lasers to a certain extent and shake the error caused, and improve the detectability of weak peak and overlap peak.

Obviously, those skilled in the art can carry out various change and modification to the present invention and not depart from the spirit and scope of the present invention.Like this, if these amendments of the present invention and modification belong within the scope of the claims in the present invention and equivalent technologies, then the present invention is also intended to comprise these change and modification.

Claims (10)

1. an analytic system for two-dimentional energy associated laser induced breakdown spectroscopy, is characterized in that, comprising: laser instrument, spectrometer, delay time generator, optical fiber, sample and computing machine;

Described laser instrument, impacts described sample for periodically emission pulse laser;

Described delay time generator is connected with described laser instrument and described spectrometer respectively, for according to the delay time preset, triggers described spectrometer collection signal;

Described spectrometer is connected with described computing machine with described optical fiber respectively, for being collected the plasma light signal that described sample sends by optical fiber.

2. system according to claim 1, is characterized in that, described delay time generator is the picosecond accurate delay system adopting FPGA to control.

3. system according to claim 1, is characterized in that, described system also comprises: converging device, described converging device and described Fiber connection, for converging the plasma light signal that described sample sends, and is delivered to described spectrometer through optical fiber.

4. system according to claim 3, is characterized in that, described converging device is the card Sa Gelin system being placed in described optical fiber front end.

5. system according to claim 3, is characterized in that, described system also comprises: beam splitter, and described beam splitter is placed in described laser emitting position, for described laser instrument is launched 10% pulsed laser energy reflex to photodiode.

6. an analytical approach for two-dimentional energy associated laser induced breakdown spectroscopy, is characterized in that, comprising:

Spectrometer is measured the dark background not placing sample, obtains background spectrum, and deducts interference and this bulk noise of described background spectrum;

Under energy perturbation state, carrying out spectral measurement, by increasing the laser energy that laser instrument is launched, obtaining described sample one dimension spectrum under breakdown conditions;

Obtain the exact numerical of laser energy, according to described exact numerical, laser power calibration and normalized are carried out to described one dimension spectrum;

Calculate two-dimensional correlation spectra according to described one dimension spectrum, described two-dimensional correlation spectra comprises: synchronous correlation spectrum and asynchronous correlation spectrum;

Be separated the self correlated peak in two-dimensional correlation spectra, intersection peak, and corresponding with one dimension spectrum.

7. method according to claim 6, is characterized in that, the exact numerical of described acquisition laser energy, carries out laser power calibration and normalized, comprising according to described exact numerical to described one dimension spectrum:

Photodiode receives the laser energy of beam splitter feedback, and measures laser energy in real time;

According to deviate, corresponding coefficient is multiplied by original spectrum, and compensates the deviation of described laser energy;

Be spectroscopic data described in window record with 50nm, carry out area normalization in each described window.

8. method according to claim 6, is characterized in that, describedly under energy perturbation state, carries out spectral measurement, by increasing the laser energy that laser instrument is launched, obtaining described sample one dimension spectrum under breakdown conditions, comprising:

When impacting first, described laser instrument take basal energy as 100-200mJ, and frequency is that the laser pulse of 10HZ impacts described sample;

After impact first, the basal energy impact sample of each increase by 5%, to obtain the spectroscopic data of gradual change.

9. method according to claim 6, is characterized in that, the described synchronous correlation spectrum calculated according to one dimension spectrum in two-dimensional correlation spectra, comprising:

Described synchronous correlation spectrum is calculated according to formula one:

${\mathrm{\Φ}}_1=\frac{1}{S_{\max }-S_{\min }}\underset{j=1}{\mathrm{\Σ}}[y_j\left({\mathrm{\υ}}_1\right)\·y_j\left({\mathrm{\υ}}_2\right)]$ Formula one

Wherein, S _maxfor the spectral intensity maximal value of described spectrometer collection, S _minfor the spectral intensity minimum value of described spectrometer collection, y _j(υ ₁) and y _j(υ ₂) be the spectra values of different-waveband.

10. method according to claim 6, is characterized in that, the described asynchronous correlation spectrum calculated according to one dimension spectrum in two-dimensional correlation spectra, comprising:

Described asynchronous correlation spectrum is calculated according to formula two:

${\mathrm{\Φ}}_2=\frac{1}{S_{\max }-S_{\min }}\underset{j=1}{\mathrm{\Σ}}\left\{y_j\left({\mathrm{\υ}}_1\right)\underset{k=1}{\mathrm{\Σ}}{y}_k\left({\mathrm{\υ}}_2\right)\right\}$ Formula two

Wherein, S _maxfor the spectral intensity maximal value of described spectrometer collection, S _minfor the spectral intensity minimum value of described spectrometer collection, y _j(υ ₁) and yk (υ ₂) be the spectra values of different-waveband.