CN201666874U - Solid material Raman gain coefficient measuring system - Google Patents

Abstract

The utility model relates to a solid material Raman gain coefficient measuring system. The system adopts the structure that the system comprises a laser pumping source; and at least one beam polarization and intensity adjusting device, at least one beam reducing system, at least one partially reflecting mirror, at least two samples to be measured with different lengths and identical material, at least one beam splitter and a changeable measuring device II are sequentially arranged in the rear of the laser pumping source, wherein the partially reflecting mirror is matched with a changeable measuring device I. The experimental circuit optical path in the method is simple and easy to be adjusted, all that is needed is to adopt the two samples to be measured to repeatedly perform the experiment, and then the Raman gain coefficient is obtained by directly calculating the data obtained through an energy meter and a CCD.

Description

The Raman gain coefficient of solid material measuring system

Technical field

The utility model relates to a kind of measuring system of Raman gain coefficienct, relates in particular to a kind of Raman gain coefficient of solid material measuring system.

Background technology

Using the laser frequency technology of raman material is used widely in scientific research and modern production.Raman gain coefficienct as one of raman material important parameter becomes the main standard of weighing the raman material performance.Measure this value and seem particularly important for the selection of raman laser material.

At present, external relevant for the report of solid Roman material gain coefficient.They mainly adopt three kinds of modes to realize: the one, adopt spontaneous method for measuring Raman spectrum (Raman band intensities of tellurite glasses, " OPTICSLETTERS ", Vol.30,2005,1156-1158), two be to use single laser pulse excited Raman method (Efficient Ramanshifting of picosecond pulses using BaWO ₄Crystal, " Optics Communications ", Vol.177,2000,397-404).The 3rd, and the method for employing laser dipulse excited Raman (Raman gain measurements in bulk glasssamples, " J.Opt.Soc.Am.B ", Vol.22,2005,1861-1867).First method is utilized the spontaneous Raman spectrum of the spontaneous Raman spectrum of testing sample and standard material to compare and is obtained the testing sample Raman gain coefficienct, experimentation must rely on the parameter constant of standard material (generally being silicon dioxide) to obtain the gain coefficient of sample to be tested, and can't not have to obtain Raman gain coefficienct under the situation of master sample by experiment.Second method utilizes psec or nanosecond pulse one way to obtain gain coefficient by the excited Raman phenomenon of raman material, used the parameter (as hypothesis spontaneous emission noise parameter) of some hypothesis in the data handling procedure, these hypothesis are not considered the influence of the difference of material to the result, do not unify to treat and the parameter of different materials made any distinction between.The transfer of excited Raman phenomenon produce power takes place when the third method is utilized two light beams by sample to be tested obtain Raman gain coefficienct, the complicated and adjusting difficulty very big (especially the overlapping condition of two burst length spatial altitudes is difficult to be met) of experimentation.

The utility model content

The purpose of this utility model is exactly for addressing the above problem, and provides a kind of and has without reference standard sample (experiment just utilizes two same material samples to be tested), need not suppose that parameter and constant (calculating according to the direct substitution formula of measurement result), light path regulate simple and measure the measuring system of advantages such as convenient (just single beam collimation and directly utilize energy meter, CCD to measure experimental result).

A kind of Raman gain coefficient of solid material measuring system, it comprises laser pumping source, set gradually at least one light beam polarization and intensity adjustments device, at least one light beam contract beam system, at least one partially reflecting mirror, at least two samples to be tested, at least one beam splitter and the formula of replacing measurement mechanism II at the laser pumping source rear, wherein partially reflecting mirror then cooperates with the formula of replacing measurement mechanism I.

Described laser pumping source is psec or ps pulsed laser and ns pulsed laser device.

Described light beam polarization and intensity adjustments device can have multiple choices, for example two polaroid or other combinations such as half-wave plate and polarizer of arranging successively.

Described sample to be tested is two different same material samples of length, and both differences in length are controlled in 20%.

Described sample to be tested is the solid material that can be applied in the Raman laser: as tungstates, vanadic acid salt, Nitrates, iodates etc.; Two end faces of sample to be tested all are coated with pump light wave band and corresponding stokes wave band anti-reflection film.

The described light beam beam system that contracts has multiple choices, adds other combinations such as concavees lens as two convex lens or convex lens.

Described replacing formula measurement mechanism I and the formula of replacing measurement mechanism II are energy meter, CCD.

Measuring method of the present utility model is:

Step 1 utilizes laser pumping source to produce nanosecond or picosecond pulse laser, contracts through light beam polarization and energy regulating system and light beam and incides partially reflecting mirror after the beam system adjustment;

Step 2, the partially reflecting mirror extraction unit is divided pump light, measure the input pulse energy with energy meter I, survey the output pulse energy with energy meter II simultaneously, use CCD measuring beam lateral dimension (in order to reduce the change of instrument position as far as possible, can measure) then accordingly with the position that CCD puts two energy meters respectively in the drawings;

The experiments of measuring data, in experiment, slowly regulate pump light pulse energy (can directly increase laser power and also can regulate light beam polarization and energy regulating system) according to per second increase by one to ten little Jiao's speed, until beginning to observe first sample (length is lacked) generation excited Raman effect, at this moment measure the preceding pump energy of incident and the stokes energy of output simultaneously with two energy meters; Measure before the sample incident respectively with CCD then and outgoing after the pulse lateral dimension; Under the situation that keeps the experimental provision invariant position, behind second sample (length is long), first sample of replacement, under same experimental conditions, to measure another and organize experimental data, the substitution formula calculates;

Step 3 is calculated according to the data that two samples to be tested record under same experimental conditions, according to formula:

$I_S\left(l\right)=I_S\left(0\right)\exp (g{I}_P\frac{1-e^{-{\mathrm{\α}}_{P}l}}{{\mathrm{\α}}_P}-{\mathrm{\α}}_{S}l)$

I wherein _s(O) and I _s(I) be respectively the stokes light intensity of Raman sample input end and output terminal, under no pump state, I _s(O) represent spontaneous emission noise, g is a Raman gain coefficienct, I _pBe the pumping laser light intensity, I is a sample length, α _pBe the pumping depletion coefficient, α _sIt is the stokes optical loss coefficient;

When placing two samples respectively and excited Raman takes place, satisfy:

$I_S\left(l_1\right)=I_S\left(0\right)\exp ({\mathrm{gI}}_P\frac{1-e^{-{\mathrm{\&alpha;}}_P{l}_1}}{{\mathrm{\&alpha;}}_P}-{\mathrm{\&alpha;}}_S{l}_1)$ With $I_S\left(l_2\right)=I_S\left(0\right)\exp ({\mathrm{gI}}_P\frac{1-e^{-{\mathrm{\&alpha;}}_{\mathrm{<figure-callout\; id="2"\; label="P\; l"\; filenames="HSA00000021015400011.png"\; state="\{\{state\}\}">P</figure-callout>}}{l}_{}{}_2}}{{\mathrm{\&alpha;}}_P}-{\mathrm{\&alpha;}}_S{l}_2)$

Be divided by by above two formulas and obtain:

$\frac{I_S\left(l_2\right)}{I_S\left(l_1\right)}=\exp (g{I}_P\frac{e^{{-\mathrm{\&alpha;}}_P{l}_1}-e^{-{\mathrm{\&alpha;}}_{\mathrm{<figure-callout\; id="2"\; label="P\; l"\; filenames="HSA00000021015400011.png"\; state="\{\{state\}\}">P</figure-callout>}}{l}_{}{}_2}}{{\mathrm{\&alpha;}}_P}-{\mathrm{\&alpha;}}_{\mathrm{<figure-callout\; id="2"\; label="S\; l"\; filenames="HSA00000021015400011.png"\; state="\{\{state\}\}">S</figure-callout>}}{l}_{}{}_2+{\mathrm{\&alpha;}}_S{l}_1)$

I wherein ₁And I ₂Be two sample length, I _pBe the pumping laser light intensity, I _s(I ₁) and I _s(I ₂) be respectively the stokes light output intensity that different length same material sample produces respectively under the same terms, bring formula into and can obtain Raman gain coefficienct g, be formulated as:

$g=\frac{\ln \left[\frac{I_S\left(l_2\right)}{I_S\left(l_1\right)}\right]+{\mathrm{\&alpha;}}_S{l}_2-{\mathrm{\&alpha;}}_S{l}_1}{I_P\frac{e^{-{\mathrm{\&alpha;}}_P{l}_1}-e^{-{\mathrm{\&alpha;}}_{\mathrm{<figure-callout\; id="2"\; label="P\; l"\; filenames="HSA00000021015400011.png"\; state="\{\{state\}\}">P</figure-callout>}}{l}_{}{}_2}}{{\mathrm{\&alpha;}}_P}}$

Pumping light intensity I _pThe pulse energy that records according to energy meter, known pulse width, the pulse waist spot that CCD measures calculate, and in like manner can calculate the light intensity I of stokes light _s(I ₁) and I _s(I ₂);

$\frac{I_S\left(l_1\right)}{I_S\left(l_2\right)}=\frac{Q_1}{{\mathrm{<figure-callout\; id="2"\; label="Q"\; filenames="HSA00000021015400011.png"\; state="\{\{state\}\}">Q</figure-callout>}}_2}\&CenterDot;\frac{{{\mathrm{\&pi;w}}_2}^2}{{{\mathrm{\&pi;w}}_1}^2}\&CenterDot;\frac{{\mathrm{\&Delta;<figure-callout\; id="2"\; label="t"\; filenames="HSA00000021015400011.png"\; state="\{\{state\}\}">t</figure-callout>}}_2}{{\mathrm{\&Delta;t}}_1}$

Wherein Q marker energy records with energy meter; ω mark laser waist spot measures with CCD; Near Δ t marker width (two pulse widths equate the excited Raman threshold value); Subscript 1 and 2 is represented two samples respectively.

From above-mentioned experimental procedure as can be seen, this experiment light path is regulated easily simple, just utilizes two samples to be tested to repeat experiment, and the data that obtain by energy meter and CCD directly calculate Raman gain coefficienct then.

The utility model is measured the system of Raman gain coefficienct, comprises that contract bundle device, partially reflecting mirror, beam splitter, energy meter, approaching sample to be tested and the CCD of two block lengths of laser pumping source, light beam polarization and intensity adjustments device, laser form.The laser that this method is utilized nanosecond or picosecond magnitude is through Raman sample generation stimulated Raman scattering to be measured, separately exports different wave length composition in the light with light-dividing device then, surveys two wavelength energy simultaneously with energy meter, with CCD photometry bundle lateral dimension.

Laser pumping source can be the laser instrument of output nanosecond or picopulse.

Light beam polarization and intensity adjustments device can have multiple choices, for example two polaroid or other combinations such as half-wave plate and polarizer of arranging successively.

The described light beam beam system that contracts has multiple choices, adds other combinations such as concavees lens as two convex lens or convex lens.

Partially reflecting mirror is used for extracting a small amount of pump light, measures pulse energy with energy meter, uses CCD measuring beam lateral dimension simultaneously.

To note for the selection of two same material raman materials must the length difference little because big difference in length can because the non co axial composition of scattered light increases and pump light exhaust the stability that influences experimental result.Two sample differences in length are controlled in 20% in the experiment.Sample to be tested can be the solid material that is applied in the Raman laser: as tungstates, vanadic acid salt, Nitrates, iodates etc.; Two end faces of sample to be tested all polish and all are coated with pump light wave band and corresponding stokes wave band anti-reflection film.Raman material can be measured the gain coefficient of different polarization direction so as required along different directions and angle cutting.

During the experiments of measuring data, when measuring earlier a shorter sample and beginning to take place the excited Raman effect, measure the pump energy before the incident and the stokes energy of output simultaneously with two probes on the energy meter.Measure before the sample incident respectively with CCD then and outgoing after the pulse lateral dimension.Keeping under the constant situation of experimental provision position and pump power, replacing than behind first short sample with the long sample of another piece, measure another group experimental data under same experimental conditions, the substitution formula calculates.

Calculate according to the data that two samples to be tested record under same experimental conditions, according to formula:

$I_S\left(l\right)=I_S\left(0\right)\exp ({\mathrm{gI}}_P\frac{1-e^{-{\mathrm{\&alpha;}}_{P}l}}{{\mathrm{\&alpha;}}_P}-{\mathrm{\&alpha;}}_{S}l)$

I wherein _s(O) and I _s(I) be respectively the stokes light intensity of raman material input end and output terminal, under no pump state, I _s(O) represent spontaneous emission noise, g is a Raman gain coefficienct, I _pBe incident pumping laser light intensity, I is a sample length, α _pBe the pumping depletion coefficient, α _sIt is the stokes optical loss coefficient;

When placing two samples respectively and excited Raman takes place, satisfy:

$I_S\left(l_1\right)=I_S\left(0\right)\exp ({\mathrm{gI}}_P\frac{1-e^{-{\mathrm{\&alpha;}}_P{l}_1}}{{\mathrm{\&alpha;}}_P}-{\mathrm{\&alpha;}}_S{l}_1)$ With $I_S\left(l_2\right)=I_S\left(0\right)\exp ({\mathrm{gI}}_P\frac{1-e^{-{\mathrm{\&alpha;}}_{\mathrm{<figure-callout\; id="2"\; label="P\; l"\; filenames="HSA00000021015400011.png"\; state="\{\{state\}\}">P</figure-callout>}}{l}_{}{}_2}}{{\mathrm{\&alpha;}}_P}-{\mathrm{\&alpha;}}_S{l}_2)$

Be divided by by above two formulas and obtain:

$\frac{I_S\left(l_2\right)}{I_S\left(l_1\right)}=\exp ({\mathrm{gI}}_P\frac{e^{-{\mathrm{\&alpha;}}_P{l}_1}-e^{-{\mathrm{\&alpha;}}_{\mathrm{<figure-callout\; id="2"\; label="P\; l"\; filenames="HSA00000021015400011.png"\; state="\{\{state\}\}">P</figure-callout>}}{l}_{}{}_2}}{{\mathrm{\&alpha;}}_P}-{\mathrm{\&alpha;}}_{\mathrm{<figure-callout\; id="2"\; label="S\; l"\; filenames="HSA00000021015400011.png"\; state="\{\{state\}\}">S</figure-callout>}}{l}_{}{}_2+{\mathrm{\&alpha;}}_S{l}_1)$

I wherein ₁And I ₂Be two sample length, I _pBe incident pumping laser light intensity, I _s(I ₁) and I _s(I ₂) be respectively the stokes light output intensity that different length same material sample produces respectively under the same terms, bring formula into and can obtain Raman gain coefficienct g, be formulated as:

$g=\frac{\ln \left[\frac{I_S\left(l_2\right)}{I_S\left(l_1\right)}\right]+{\mathrm{\&alpha;}}_S{l}_2-{\mathrm{\&alpha;}}_S{l}_1}{I_P\frac{e^{-{\mathrm{\&alpha;}}_P{l}_1}-e^{-{\mathrm{\&alpha;}}_{\mathrm{<figure-callout\; id="2"\; label="P\; l"\; filenames="HSA00000021015400011.png"\; state="\{\{state\}\}">P</figure-callout>}}{l}_{}{}_2}}{{\mathrm{\&alpha;}}_P}}$

Pumping light intensity I _pThe pulse energy, known pulse width, the CCD that record according to energy meter measure pulse waist spot and calculate, and in like manner can calculate the light intensity I of stokes light _s(I ₁) and I _s(I ₂);

$\frac{I_S\left(l_1\right)}{I_S\left(l_2\right)}=\frac{Q_1}{{\mathrm{<figure-callout\; id="2"\; label="Q"\; filenames="HSA00000021015400011.png"\; state="\{\{state\}\}">Q</figure-callout>}}_2}\&CenterDot;\frac{{{\mathrm{\&pi;w}}_2}^2}{{{\mathrm{\&pi;w}}_1}^2}\&CenterDot;\frac{{\mathrm{\&Delta;<figure-callout\; id="2"\; label="t"\; filenames="HSA00000021015400011.png"\; state="\{\{state\}\}">t</figure-callout>}}_2}{{\mathrm{\&Delta;t}}_1}$

Wherein Q marker energy records with energy meter; ω mark laser waist spot measures with CCD; Near Δ t marker width (two pulse widths equate the excited Raman threshold value); Subscript 1 and 2 is represented two samples respectively.

Compare with other three kinds of methods, this method has the advantage of himself.Compare with method one, this method can not have to obtain Raman gain coefficienct under the situation of master sample without standard model.Compare with method two, utilize experiment measuring value substitution formula to calculate in the gain calculating fully, do not suppose any parameter constant, avoided because parameter is chosen Different Effects result of calculation, this method fully takes into account the characteristics that different materials has different parameter constants.In addition, this method light path is regulated simply, measuring process is rapidly convenient, has overcome to test in the method three to regulate (especially two burst lengths space overlaps adjusting) shortcoming that difficulty is big, experimentation is complicated.

Description of drawings

Fig. 1 is an experiment structural representation of the present utility model.

Wherein: 1 laser pumping source; 2 polaroid I; 3 polaroid II; (2 and 3 combinations are a kind of selections of light beam polarization and intensity adjustments device) 4 convex lens I; 5 convex lens II (4 and 5 combinations be light beam contract a kind of selection of beam system); 6 change formula measurement mechanism I; 7 partially reflecting mirrors; 8 samples to be tested; 9 beam splitters; 10 change formula measurement mechanism II.

Embodiment

Below in conjunction with accompanying drawing and embodiment the utility model is described further.

Examples of implementation:

Among Fig. 1, a kind of Raman gain coefficient of solid material measuring system, it comprises laser pumping source 1, set gradually at least one light beam polarization and intensity adjustments device (for example forming) by diagram I2 and two polaroids of II3 at laser pumping source 1 rear, at least one light beam beam system (for example forming) that contracts by diagram I4 and two convex lens of II5, at least one partially reflecting mirror 7, at least two samples to be tested 8 (using successively), at least one beam splitter 9, replacing formula measurement mechanism II10, wherein 7 of partially reflecting mirrors cooperate with the formula of replacing measurement mechanism I6, usefulness energy instrumentation pulse energy and with CCD photometry bundle lateral dimension.Replacing formula measurement mechanism I6 and change formula measurement mechanism II10 and be energy meter and CCD, these equipment all finish DATA REASONING (what wherein two energy meters were used is a machine two-way, and CCD can reuse with a set of equipment) in turn at same position.

Laser pumping source 1 is Nd ³⁺: the 1064nm psec polarization laser that the YAG Q-switch and mode-locking produces

Light beam polarization and intensity adjustments device are made up of two polaroid I2 and polaroid II3 that arrange successively.

The light beam beam system that contracts is made up of two convex lens I4 and convex lens II5.

The concrete model of each equipment is:

The PY61C dye laser that laser pumping source 1 is produced for continuum company (output psec 1064nm laser);

The focal length of convex lens I4 is 500mm; The focal length of convex lens II5 is 100mm;

Energy is counted Molectron EMP2000 type, and two probe all adopts the J50-YAG type;

Partially reflecting mirror 7 is the level crossing of 1064nm transmitance 98.3%;

Sample to be tested 8 is that 3 * 3 * 17mm c cuts YVO ₄Crystal and 3 * 3 * 20mm c cut YVO ₄Crystal (two crystal are by forming with the piece crystal-cut, and the anti-reflection film of 1000nm-1200nm wave band is all plated on the surface)

Beam splitter 9 be the 1064nm reflectivity greater than 99.5% and 1176nm to 1180nm place transmitance greater than 99% level crossing;

Lay energy meter respectively before and after the light path of sample to be tested crystal 8, two energy meters connect a machine binary channels, and probe also adopts the J50-YAG type.

CCD is a DUMA BeamOn HR model, respectively at sample to be tested crystal 8 light path fore-and-aft survey signals.

Measuring method of the present utility model is:

Step 1 utilizes laser pumping source to produce the laser of 1064nm picosecond magnitude, after adjusting through two polaroids and two convex lens through partially reflecting mirror;

Step 2, the partially reflecting mirror extraction unit is divided pump light, with energy meter I measure portion input pulse energy, survey the output pulse energy with energy meter II simultaneously, use CCD measuring beam lateral dimension (, can measure in the position of putting two energy meters respectively) then respectively successively with CCD in order to reduce the change of instrument position as far as possible;

The experiments of measuring data, in experiment, slowly regulate pump light pulse energy (can directly increase laser power and also can regulate light beam polarization and energy regulating system) according to per second increase by one to ten little Jiao's speed, (3 * 3 * 17mm) the excited Raman effect takes place, and at this moment measures preceding pump energy of incident and the stokes energy after the outgoing simultaneously with two energy meters until beginning to observe first crystal; Measure before the crystal incident respectively with CCD then and outgoing after the pulse lateral dimension; Under the situation that keeps the experimental provision invariant position, (behind first crystal of 3 * 3 * 20mm) replacements, measure another group experimental data under same experimental conditions, the substitution formula calculates with second crystal;

Step 3 is calculated according to the data that two sample to be tested crystal record under same experimental conditions, according to formula:

$I_S\left(l\right)=I_S\left(0\right)\exp ({\mathrm{gI}}_P\frac{1-e^{-{\mathrm{\&alpha;}}_{P}l}}{{\mathrm{\&alpha;}}_P}-{\mathrm{\&alpha;}}_{S}l)$

I wherein _s(O) and I _s(I) be respectively the stokes light intensity of Raman crystal input end and output terminal, under no pump state, I _s(O) represent spontaneous emission noise, g is a Raman gain coefficienct, I _pBe incident pumping laser light intensity, I is a crystal length, α _pBe the pumping depletion coefficient, α _sIt is the stokes optical loss coefficient;

When placing two crystal respectively and excited Raman takes place, satisfy:

$I_S\left(l_1\right)=I_S\left(0\right)\exp ({\mathrm{gI}}_P\frac{1-e^{-{\mathrm{\&alpha;}}_P{l}_1}}{{\mathrm{\&alpha;}}_P}-{\mathrm{\&alpha;}}_S{l}_1)$ With $I_S\left(l_2\right)=I_S\left(0\right)\exp ({\mathrm{gI}}_P\frac{1-e^{-{\mathrm{\&alpha;}}_{\mathrm{<figure-callout\; id="2"\; label="P\; l"\; filenames="HSA00000021015400011.png"\; state="\{\{state\}\}">P</figure-callout>}}{l}_{}{}_2}}{{\mathrm{\&alpha;}}_P}-{\mathrm{\&alpha;}}_S{l}_2)$

Be divided by by above two formulas and obtain:

$\frac{I_S\left(l_2\right)}{I_S\left(l_1\right)}=\exp (g{I}_P\frac{e^{-{\mathrm{\&alpha;}}_P{l}_1}-e^{-{\mathrm{\&alpha;}}_{\mathrm{<figure-callout\; id="2"\; label="P\; l"\; filenames="HSA00000021015400011.png"\; state="\{\{state\}\}">P</figure-callout>}}{l}_{}{}_2}}{{\mathrm{\&alpha;}}_P}-{\mathrm{\&alpha;}}_{\mathrm{<figure-callout\; id="2"\; label="S\; l"\; filenames="HSA00000021015400011.png"\; state="\{\{state\}\}">S</figure-callout>}}{l}_{}{}_2+{\mathrm{\&alpha;}}_S{l}_1)$

I wherein ₁And I ₂Be two crystal lengths, I _pBe the pumping laser light intensity, I _s(I1) and I _s(I ₂) be respectively the stokes light output intensity that different length same material crystal produces respectively under the same terms, bring formula into and can obtain Raman gain coefficienct g, be formulated as:

$g=\frac{\ln \left[\frac{I_S\left(l_2\right)}{I_S\left(l_1\right)}\right]+{\mathrm{\&alpha;}}_S{l}_2-{\mathrm{\&alpha;}}_S{l}_1}{I_P\frac{e^{-{\mathrm{\&alpha;}}_P{l}_1}-e^{-{\mathrm{\&alpha;}}_{\mathrm{<figure-callout\; id="2"\; label="P\; l"\; filenames="HSA00000021015400011.png"\; state="\{\{state\}\}">P</figure-callout>}}{l}_{}{}_2}}{{\mathrm{\&alpha;}}_P}}$

Pumping light intensity I _pThe pulse energy, known pulse width, the CCD that record according to energy meter measure pulse waist spot and calculate, thereby can calculate the light intensity I of stokes light _s(I ₁) and I _s(I ₂) satisfy;

$\frac{I_S\left(l_1\right)}{I_S\left(l_2\right)}=\frac{Q_1}{{\mathrm{<figure-callout\; id="2"\; label="Q"\; filenames="HSA00000021015400011.png"\; state="\{\{state\}\}">Q</figure-callout>}}_2}\&CenterDot;\frac{{{\mathrm{\&pi;<figure-callout\; id="2"\; label="w"\; filenames="HSA00000021015400011.png"\; state="\{\{state\}\}">w</figure-callout>}}_2}^2}{{{\mathrm{\&pi;w}}_1}^2}\&CenterDot;\frac{{\mathrm{\&Delta;<figure-callout\; id="2"\; label="t"\; filenames="HSA00000021015400011.png"\; state="\{\{state\}\}">t</figure-callout>}}_2}{{\mathrm{\&Delta;t}}_1}$

Wherein Q marker energy records with energy meter; ω mark laser waist spot measures with CCD; Near Δ t marker width (two pulse widths equate the excited Raman threshold value); Subscript 1 and 2 is represented two crystal respectively.

From above-mentioned experimental procedure as can be seen, this experiment light path is regulated easily simple, just utilizes two samples to be tested to repeat experiment, and the data that obtain by energy meter and CCD directly calculate Raman gain coefficienct then.

Experiment points for attention and explanation

During 1 use different length sample, use short one earlier, re-use than another long piece, and it is equally big to guarantee that two samples are measured stokes light time pump light intensities respectively.

2 prevent to test in pumping too Johnson ﹠ Johnson become second order and the light of other frequencies such as high-order stokes and anti-stokes (should be controlled at pump power when the excited Raman effect just takes place when therefore using shorter sample) more.

3 two sample length difference are within 20%, be that pump intensity is all near the excited Raman threshold value in order to guarantee to measure, depletion conditions and stokes do not have obvious scattered through angles effect (the pumping light intensity can produce non axial stimulated Raman scattering when several times of threshold values) thereby satisfy pumping.

Claims (7)

1. Raman gain coefficient of solid material measuring system, it is characterized in that, it comprises laser pumping source, set gradually at least one light beam polarization and intensity adjustments device, at least one light beam contract beam system, at least one partially reflecting mirror, at least two different lengths, same material sample to be tested, at least one beam splitter and the formula of replacing measurement mechanism II at the laser pumping source rear, wherein partially reflecting mirror then cooperates with the formula of replacing measurement mechanism I.

2. Raman gain coefficient of solid material measuring system as claimed in claim 1 is characterized in that, described laser pumping source is the laser pulse device of psec or nanosecond pulse width.

3. Raman gain coefficient of solid material measuring system as claimed in claim 1 is characterized in that, described light beam polarization and intensity adjustments device are two polaroid or half-wave plate and the polarizers arranged successively.

4. Raman gain coefficient of solid material measuring system as claimed in claim 1 is characterized in that, described sample to be tested is the different solid materials of the same race of two block lengths, and both differences in length are controlled in 20%.

5. Raman gain coefficient of solid material measuring system as claimed in claim 4 is characterized in that, described sample to be tested is tungstates, vanadic acid salt, Nitrates or iodates solid material; Two end faces of sample to be tested polish and all are coated with pump light wave band and corresponding stokes wave band anti-reflection film.

6. Raman gain coefficient of solid material measuring system as claimed in claim 1 is characterized in that, the described light beam beam system that contracts is that two convex lens or convex lens add the concavees lens structure.

7. Raman gain coefficient of solid material measuring system as claimed in claim 1 is characterized in that, described replacing formula measurement mechanism I and the formula of replacing measurement mechanism II are energy meter and CCD.

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