CN104926114A - Phosphate laser neodymium glass - Google Patents

Abstract

The invention provides phosphate laser neodymium glass. The phosphate laser neodymium glass is higher in stimulated emission cross section, small in thermo-optical coefficient and suitable for high-power laser devices. The phosphate laser neodymium glass comprises, by mol, 50%-70% of P2O5, 1%-15% of Al203, 5%-25% of MO, 10%-20% of R2O, 0.5%-5% of R2O3 and 0.5%-5% of Nb2O5, wherein M in the MO is one or more of Ba, Mg and Zn; R in the R2O is one ore more of LI, Na and K, and R in the R2O3 is one or more of Y, La and Nd. According to the phosphate laser neodymium glass, all components are reasonably allocated, the non-linear refractive index n2 of the obtained phosphate laser neodymium glass is 1.16-1.24(10<-13>esu), the stimulated emission cross section sigma of the obtained phosphate laser neodymium glass is 4.0-4.8(10<-20>cm<2>), and the thermo-optical coefficient ds/dT(20-60 DEG C) of the obtained phosphate laser neodymium glass is 1-2 (10<-7>/K).

Description

Phosphate laser neodymium glass

Technical field

The present invention relates to a kind of phosphate laser neodymium glass, particularly relate to that a kind of stimulated emission cross section is high, thermo-optical coeffecient is low, be suitable for the laser glass of device of high power laser.

Background technology

Because neodymium glass fluorescence lifetime is long, stimulated emission cross section is large, block sheet is large and can manufacture, be thus used widely in laser system.Neodymium glass also has good energy storage effect, becomes the first-selected operation material of high power laser system multiplying arrangement, the portfire of such as U.S. LLNL and the God Light device of China, is all as amplification medium with neodymium glass.The spectral quality of neodymium glass directly affects device of high power laser design, and the spectral quality therefore studying neodymium glass is particularly important to device of high power laser design.The spectral quality of neodymium glass comprises uptake factor, launches transition probability, metastable state fluorescence lifetime, radiative quantum efficiency, stimulated emission cross section and excited state absorption moment of dipole etc.Wherein, stimulated emission cross section is the physical quantity the most basic weighing working-laser material optical quality, is one of most important parameters of design device of high power laser.

The conventional absorption of spectroscopy and emission cross section represent absorption and emission probability.Cross section has the dimension of area, and itself and the ratio of beam area represent that one absorbs or launching centre (atom or molecule) absorbs or the probability of utilizing emitted light radiation.Emission cross section is the threshold value of assessment material and the important spectrum parameter of slope efficiency.The size of emission cross section directly has influence on the gain efficiency of neodymium glass, and therefore, it plays a part key in laser system design.

Phosphate laser neodymium glass is mainly used as the operation material of laser amplifier in device of high power laser.On the one hand, in order to realize high gain, require that the stimulated emission cross section of neodymium glass is large as far as possible, fluorescence lifetime is long as far as possible.In addition, in order to obtain larger output energy, adopt the neodymium glass of high density as amplification material.But along with increasing of Concentration of Neodymium Ion in Czochralski in neodymium glass, stimulated emission cross section will reduce thereupon.Therefore, how designing suitable material composition, while maintenance glass has high Concentration of Neodymium Ion in Czochralski, improve its stimulated emission cross section further, to realize higher laser gain, is the important topic of neodymium glass research.

Current domestic existing phosphate laser neodymium glass, as N31 glass (N31 laser neodymium glass acceptance of materials report, in December, 1998), its stimulated emission cross section is not high by (3.9 × 10 ^-20cm ²), its thermo-optical coeffecient (dS/dT=14 × 10 ^-7/ K) comparatively large, the requirement of following device of high power laser to the low thermo-optic effect of laser glass can not be met; Thermo-optical coeffecient (dS/dT=0.3 × 10 disclosed in CN 1765795A ^-7/ K) less, but its stimulated emission cross section is not high by (3.9 × 10 yet ^-20cm ²).

Summary of the invention

Technical problem to be solved by this invention is to provide that a kind of stimulated emission cross section is high, thermo-optical coeffecient is little, be applicable to the phosphate laser neodymium glass of device of high power laser.

The solution that technical solution problem of the present invention adopts is: phosphate laser neodymium glass, and the molar percentage composition of its moiety comprises: P ₂o ₅50-70mol%; Al ₂o ₃1-15mol%; MO 5-25mol%, wherein, M is one or more in Ba, Mg, Zn; R ₂o 10-20mol%, wherein, R is one or more in Li, Na, K; R ₂o ₃0.5-5mol%, wherein, R is one or more in Y, La, Nd; Nb ₂o ₅0.5-5mol%.

Further, wherein, BaO 5-20mol% and/or ZnO 1-5mol% and/or MgO 0-5mol%.

Further, wherein, MO 10-20mol%.

Further, wherein, Y ₂o ₃0-3mol% and/or La ₂o ₃0-3mol% and/or Nd ₂o ₃0-3mol%.

Further, wherein, Al ₂o ₃2-10mol%.

Further, wherein, BaO 10-18mol%.

Further, the scope of the fluorescence lifetime of described glass is 315-325 μ s.

Further, the nonlinear refractive index n of described glass ₂be 1.16 ~ 1.24 (10 ^-13esu).

Further, the stimulated emission cross section σ of described glass is 4.0 ~ 4.8 (10 ^-20cm ²).

Further, the thermo-optical coeffecient ds/dT (20-60 DEG C) of described glass is 1 ~ 2 (10 ^-7/ K).

The invention has the beneficial effects as follows: the present invention passes through each component of reasonable disposition and content thereof, the nonlinear refractive index n of the phosphate laser neodymium glass obtained ₂be 1.16 ~ 1.24 (10 ^-13esu), stimulated emission cross section σ is 4.0 ~ 4.8 (10 ^-20cm ²), thermo-optical coeffecient ds/dT (20-60 DEG C) is 1 ~ 2 (10 ^-7/ K), be applicable to device of high power laser.

Accompanying drawing explanation

Fig. 1 is the absorption spectrum of the glass of the embodiment of the present invention 6.

Fig. 2 is the fluorescence spectrum of the glass of the embodiment of the present invention 6.

Embodiment

Below in conjunction with embodiment and accompanying drawing, the invention will be further described, but should not limit the scope of the invention with this.

The technology of the present invention route is at not obvious increase neodymium glass nonlinear refractive index n ₂with under the prerequisite of thermo-optical coeffecient ds/dT, introduce the oxide compound that a certain amount of positively charged ion electric field is more weak, to increase Nd ³⁺the asymmetry that coordination is around normal, thus the transmitting transition probability A improving neodymium glass _rad.Stimulated emission cross section σ is as follows with the relation of launching transition probability:

$\mathrm{\&sigma;}=\frac{{\mathrm{\&lambda;}}_p^4}{8\mathrm{\&pi;}{\mathrm{cn}}^2}\frac{1}{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{\mathrm{eff}}}{A}_{\mathrm{rad}}---\left(1\right)$

In formula (1): λ _pit is the peak wavelength of neodymium glass emmission spectrum; C is the light velocity in vacuum; N is wavelength X _pspecific refractory power; Δ λ eff is the effective line width of glass fluorescence emission spectrum.

Concrete, introduce the monovalent base metal oxide Li that specific refractory power is little in glass formula of the present invention ₂o, Na ₂o, K ₂one or more in O, and one or more in little divalent alkaline-earth metal oxide M gO, ZnO, the BaO of specific refractory power, to reduce specific refractory power and the dispersion of phosphate laser neodymium glass, reach and reduce nonlinear refractive index n ₂object; Meanwhile, not obvious affect the prerequisite of glass stimulated emission cross section under, suitably introduce A1 ₂o ₃not only can improve the chemical stability of glass, can also reduce the thermo-optical coeffecient dS/dT of glass, the temperature variation that namely light laser causes can not cause the change of light path.

The transmitting transition probability A of phosphate laser neodymium glass _radlarge reason is Nd ³⁺the asymmetry in ligand field.The positively charged ion electric field of silicate glass is stronger, cancellated distortion and Nd ³⁺the asymmetry in ligand field is larger; In contrast, because the cation sites of phosphate glass carries out chain connection, therefore positively charged ion electric field is more weak, and it is more irregular that chain connects shape arrangement, Nd ³⁺the asymmetry in ligand field is around also just large.Therefore, at not obvious raising nonlinear refractive index n ₂prerequisite under, introduce the Y that a certain amount of positively charged ion electric field is weak ₂o ₃, La ₂o ₃deng oxide compound, the transmitting transition probability A of neodymium glass can be significantly improved _rad, thus improve the stimulated emission cross section of neodymium glass.

The preparation method of phosphate laser neodymium glass of the present invention, can comprise the following steps:

1) selected glass formula, weighs each raw material;

2) raw material is fully mixed, form compound;

3) silicon carbide smelting furnace is warmed up to 1300-1400 DEG C, in the quartzification hopper being divided by described compound 20-25Kg/h to join equably in silicon carbide smelting furnace;

4) in described quartzification hopper, O is passed into ₂+ CC1 ₄gas mixture, airshed is 1-2L/ minute;

5) after stopping ventilation, glass metal is injected platinum crucible, to glass metal clarification 3-4 hour at 1350-1450 DEG C;

6) at 1250-1350 DEG C, mechanical stirring 6-10 hour is carried out to glass metal;

7) be poured in graphite jig by obtained glass metal and shape, annealing cools.

The testing method of the indices of glass of the present invention is as follows:

1) nonlinear refractive index n ₂testing method

The second nonlinear refractive index n of glass ₂express with following formula:

$n_2=\frac{68{(n_d^2+2)}^2(n_d-1)}{\mathrm{\&upsi;}\{1.517+[\mathrm{\&upsi;}(n_d^2+2)(n_d+1)]/6n_d{\}}^{1/2}}---\left(2\right)$

In formula (2): n _dfor glass is in the specific refractory power at 587.6nm wavelength place; υ is the Abbe number of glass, and calculation formula is:

$\mathrm{\&upsi;}=\frac{n_d-1}{n_F-n_c}---\left(3\right)$

In formula (3): n _f, n _cbe respectively the specific refractory power of glass at 486.1nm and 656.3nm wavelength place.N _d, n _f, n _cobtain by the test of GMR-1D precision goniometer.

Through test, the nonlinear refractive index n of glass of the present invention ₂be 1.16 ~ 1.24 (10 ^-13esu).

2) testing method of the stimulated emission cross section σ of glass

Uptake factor integration ∫ k (λ) the d λ of electronics dipole and the strength relationship of spectral line of absorption as follows:

$\underset{\mathrm{band}}{\&Integral;}k\left(\mathrm{\&lambda;}\right)\mathrm{d\&lambda;}=\frac{8N_0{\mathrm{\&pi;}}^3{e}^2\stackrel{\&OverBar;}{\mathrm{\&lambda;}}}{2\mathrm{hc}(2J+1)}\frac{{(n^2+2)}^2}{9n}S---\left(4\right)$

In formula (4): k (λ) is the uptake factor of wavelength X; N ₀neodymium ion (Nd ³⁺) concentration; it is the mean wavelength of absorption band; J is ground state angular momentum summation; N is specific refractory power; E has been electric electricity; C is the light velocity in vacuum; H is quantum of action.

According to Judd-Ofelt model, initial level J| (S, L) J> is to final state energy level J ' | and spectral line intensity of (S ', L ') J ' > electronics dipole transition is:

$S=\underset{t=\mathrm{2,4,6}}{\mathrm{\&Sigma;}}{\mathrm{\&Omega;}}_t|<(S,L)J|U^{\left(t\right)}|{|(S^{\&prime;},L^{\&prime;})J^{\&prime;}>|}^2---\left(5\right)$

In formula (5): it is the matrix element of Judd-Ofelt model; <||U ^(t)|| > is Nd ³⁺absorption jump matrix element, is calculated the digital solution of unit tensor by people such as Carnall.

Glass sample is processed into 1cm thick, two logical light face parallelism are within 1 ', and with the spectral line of absorption of Hitachi U-4100 spectrophotometer test sample, useful range is 350 ~ 1100nm, and be absorbed spectrum.

According to formula (4), (5) and the spectral line of absorption of various concentration samples and the transition matrix element of neodymium ion, adopt method of least squares to carry out matching to spectral line of absorption, obtain the Ω of various concentration _t(t=2,4,6).Pass through Ω _tbeginning energy level can be obtained | (S ', L ') J ' > is to energy level radiative transistion probability be:

$A[(S^{\&prime;},{\stackrel{\&OverBar;}{L}}^{\&prime;})J^{\&prime;};(\stackrel{\&OverBar;}{S},\stackrel{\&OverBar;}{L})\stackrel{\&OverBar;}{J}]=\frac{64{\mathrm{\&pi;}}^4{e}^{2}n(n^2+2)}{27h(2J^{\&prime;}+1){\stackrel{\&OverBar;}{\mathrm{\&lambda;}}}^3}\underset{t=2,4,6}{\mathrm{\&Sigma;}}{\mathrm{\&Omega;}}_t=|<S^{\&prime;},L^{\&prime;})J^{\&prime;}\left|U^{\left(t\right)}\right|{|(\stackrel{\&OverBar;}{S},\stackrel{\&OverBar;}{L})\stackrel{\&OverBar;}{J}>|}^2---\left(6\right)$

The effective line width Δ λ eff of test sample.Sample is processed into 1mm thick, then uses the fluorescence spectrum of fluorescence spectrophotometer measure sample.By the fluorescence band integration at 1053nm place, the integrated intensity obtained, divided by the fluorescence intensity of 1053nm, is exactly the effective line width of 1053nm, that is:

$\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{\mathrm{eff}}=\&Integral;I\left(\mathrm{\&lambda;}\right)\mathrm{d\&lambda;}/I_{1053}---\left(7\right)$

Formula (6), (7) calculation result are brought in formula (1), namely calculates the stimulated emission cross section of sample.

Through test, the stimulated emission cross section σ of glass of the present invention is 4.0 ~ 4.8 (10 ^-20cm ²).

3) testing method of thermo-optical coeffecient ds/dT

The test of thermo-optical coeffecient ds/dT is obtained by following expression measuring and calculation:

$\frac{\mathrm{ds}}{\mathrm{dT}}=(n-1)\mathrm{\&alpha;}+\frac{\mathrm{dn}}{\mathrm{dT}}---\left(8\right)$

In formula (8): n is the specific refractory power of glass; Dn/dT is the thermal refractive index coefficient of glass, obtains by the test of GMR-1D precision goniometer; α is the thermal expansivity of glass, uses the test of DIL-402C thermal dilatometer.

Through test, the thermo-optical coeffecient ds/dT (20-60 DEG C) of glass of the present invention is 1 ~ 2 (10 ^-7/ K).

4) testing method of fluorescence lifetime

Sample is processed into 1mm thick, carries out transient state spectrum test by fluorescence spectrophotometer, the Fitting Calculation is carried out to transient state spectrum and obtains fluorescence lifetime.

Through test, the scope of fluorescence lifetime of the present invention is 315-325 μ s.

Specific embodiments of the invention (1-10) are shown in Table 1.The composition (molar percentage) of glass, fluorescence life τ (μ s), nonlinear refractive index n is given in table 1 ₂(10 ^-13esu), the stimulated emission cross section σ (10 of glass ^-20cm ²) and thermo-optical coeffecient ds/dT.

Table 1

By the sample that the glass processing of above-described embodiment 6 becomes 1cm thick, test its absorption spectrum with spectrophotometer, obtain absorption spectrum curve needed for its stimulated emission cross section measuring and calculation, as shown in Figure 1.

By the sample that the glass processing of above-described embodiment 6 becomes 1mm thick, measure its fluorescence spectrum by fluorescence spectrophotometer, obtain its fluorescent spectrum curve needed for stimulated emission cross section measuring and calculation, as shown in Figure 2.

Claims (10)

1. phosphate laser neodymium glass, is characterized in that, the molar percentage composition of its moiety comprises: P ₂o ₅50-70mol%; Al ₂o ₃1-15mol%; MO 5-25mol%, wherein, M is one or more in Ba, Mg, Zn; R ₂o 10-20mol%, wherein, R is one or more in Li, Na, K; R ₂o ₃0.5-5mol%, wherein, R is one or more in Y, La, Nd; Nb ₂o ₅0.5-5mol%.

2. phosphate laser neodymium glass as claimed in claim 1, is characterized in that, wherein, and BaO 5-20mol% and/or ZnO 1-5mol% and/or MgO 0-5mol%.

3. phosphate laser neodymium glass as claimed in claim 1, is characterized in that, wherein, and MO 10-20mol%.

4. phosphate laser neodymium glass as claimed in claim 1, is characterized in that, wherein, and Y ₂o ₃0-3mol% and/or La ₂o ₃0-3mol% and/or Nd ₂o ₃0-3mol%.

5. phosphate laser neodymium glass as claimed in claim 1, is characterized in that, wherein, and Al ₂o ₃2-10mol%.

6. phosphate laser neodymium glass as claimed in claim 1, is characterized in that, wherein, and BaO 10-18mol%.

7. phosphate laser neodymium glass as claimed in claim 1 or 2, it is characterized in that, the scope of the fluorescence lifetime of described glass is 315-325 μ s.

8. phosphate laser neodymium glass as claimed in claim 1 or 2, is characterized in that, the nonlinear refractive index n of described glass ₂be 1.16 ~ 1.24 (10 ^-13esu).

9. phosphate laser neodymium glass as claimed in claim 1 or 2, it is characterized in that, the stimulated emission cross section σ of described glass is 4.0 ~ 4.8 (10 ^-20cm ²).

10. phosphate laser neodymium glass as claimed in claim 1 or 2, it is characterized in that, the thermo-optical coeffecient ds/dT (20-60 DEG C) of described glass is 1 ~ 2 (10 ^-7/ K).