Photoinduced piezooptics effect in TeO2–Ga2O3 glasses

Accepted Manuscript Photoinduced piezooptics effect in TeO2-Ga2O3 glasses K. Ozga, A.O. Fedorchuk, P. Armand PII:

S1293-2558(15)00135-1

DOI:

10.1016/j.solidstatesciences.2015.06.001

Reference:

SSSCIE 5141

To appear in:

Solid State Sciences

Received Date: 3 March 2015 Revised Date:

5 May 2015

Accepted Date: 2 June 2015

Please cite this article as: K. Ozga, A.O. Fedorchuk, P. Armand, Photoinduced piezooptics effect in TeO2-Ga2O3 glasses, Solid State Sciences (2015), doi: 10.1016/j.solidstatesciences.2015.06.001. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

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80TeO2-20Ga2O3

11

75TeO2-25Ga2O3

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πxxyy [m /N] *10

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ACCEPTED MANUSCRIPT Photoinduced piezooptics effect in TeO2-Ga2O3 glasses K. Ozga a, A.O. Fedorchuk b, P. Armand c

Institute of Electronics and Control System, Faculty of Electrical Engineering, Czestochowa University of

Technology, Al. Armii Krajowej 17, Czestochowa 42-200, Poland b

Lviv National University of Veterinary Medicine and Biotechnologies, Department of Inorganic and

Organic Chemistry, Pekarska St. 50, 79010 Lviv, Ukraine c

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a

Institut Charles Gerhardt Montpellier (ICGM), UMR 5253 CNRS-UM-ENSCM, C2M, Université de

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* Corresponding author: [email protected]

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Montpellier, CC1504, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France.

Abstract: We have found that during the bicolor illumination by two bociolor coherent wavelengths

1540nm/770 nm there occurred substantial changes of the elastooptical non-diagonal

coefficients at 1150 nm cw laser wavelength. They are maximal at power densities 400…500 MW/cm2. The studies have shown that the maximal effect exists for ultra-fast quenching glasses and occurs after the 1-2 min of the treatment. The switching off of the optical treatment leads to the of the photoinduced piezooptics at about 100 ms. The observed changes are

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disappearance

explained within the photoinduced changes of the charge density distribution for the principal structural clusters within a framework of the DFT approach. The studies were done both for

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diagonal as well as off-diagonal piezooptical effect (POE) tensor components.

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Keywords: tellurite glasses; optical materials; piezo-optic effect

1. Introduction

The search of novel materials which may be effectively operated by the laser beams in order to create optical modulators, deflectors, triggers etc is very important task [1, 2]. The basic parameters for the changes are electrooptical coefficients [3, 4], acoustooptical parameters [5], magnetooptical susceptibilities [6]. The use of the piezooptical operation was just done for some of the materials like nanofilms [7], glasses [8], nanocrystals [9] etc. However there is still a necessity to enhance the efficiency of the obtained changes and to decrease the driving powers. From this point of view and following the general quantum chemical evaluations one can expect that the tellurite and oxide 1

ACCEPTED MANUSCRIPT complex glasses may be promising here. Particular interest here presents the bicolor coherent treatment [10] which forms some acentricity and the macroscopic operation by their ground state dipole moments playing the crucial role here. In the present work we will explore the optically stimulated piezo-optics using the bicolor

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treatment by two coherent beams originating from two types of the laser. The first one the Nd: YAG lasers operating at 1064 nm and the second one the Er: glass lasers operating at 1540 nm.

2. Crystallochemistry aspect

For the system TeO2–Ga2O3 in the range between the compounds TeO2 and Ga2Te4O11 is

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observed a glass-formation range [11, 12]. The authors [13] indicate a presence in the glass-like phase some ions surrounding Te4+ and Te6+. The existence of the mentioned ions may be of different

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origin .

Tellurium oxide has three polymorphic modifications: α-TeO2 (SG P41212 (No. 92); a = 4.8082, c = 7.6120 Å) [14], β-TeO2 (SG Pbca (No. 61); a = 5.464, b = 5.607, c = 12.0350 Å) [15] and γTeO2 (SG P212121 (No. 19); a = 4.351, b = 4.898, c = 8.5760 Å) [16]. Depending on the inter-atomic distances of the Te-O which are taken into account their structure may be presented as tetrahedral or octahedral packages which is formed by oxygen atoms surrounding Te (see Fig. 1). The tetrahedral

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may be presented as a results of removement from the octahedral position some atoms which have the bond distances higher than sum of ionic radiuses for Te and O in octahedral coordination. In octahedral coordination some inter-atomic distances (see Fig. 1) are situated outside the sum of radiuses (Te+4 = 0.97 Å, O-2 = 1.32 Å [17]) of the corresponding elements. Within a framework of

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the chosen (octahedral) polyhedral the Te atoms are situated near the edges of octahedral. Such space acentricity may cause occurrence of local ground state dipole moment. An analysis of Te

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coordination has shown that during polymorphic phase transformations for these compound there is significant change of atomic package. Such asymmetric coordination for Te in the studied structure leads to changes in polyhedral coordination. For instance, for structures α and γ each polyhedral is coordinated by the same polyhedral. For the β-phase each polyhedral is surrounded by 11 same polyhedral connected by apices. Such transformations for the polytypes require substantial shifts of atoms during the phase transformations and during the quick cooling and glass formation where the short range order is saved , however the long range order is destroyed.

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ACCEPTED MANUSCRIPT For the system TeO2–Ga2O3 interaction of these two oxides - TeO2 and Ga2O3 leads to formation of ternary compound Ga2Te4O11 (SG P1 (1); a = 5.125, b = 6.559, c = 8.173 Å, α = 75.06, β = 89.25, γ = 69.62°) [18] and to situation of polyhedral and coordination formed by oxygen atoms surrounding Te (see Fig. 2). Following this figure Te atoms are situated in acentric positions being

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in glass-like state are able to form additional local polarization. The Ga2TeO6 crystalline structure (SG P42/mnm (136); a = 4.545, c = 8.963 Å) [19], may be presented as a package of oxygen formed polyhedral around the Te (see Fig. 3). The Ga atoms are situated in the inter-sites between these polyhedral. To avoid their appearance in the glass phase the thermo-annealing better to conduct in the inert atmosphere.

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Another possible fragments in the glass formation may be gallium oxide gallium oxide (IІІ) has two polymorphic modifications : α-Ga2O3 (SG R-3c h (167); a = 4.976, c = 13.382 Å) [20] and β-

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Ga2O3 (SG C12/m1 (12); a = 12.202, b = 3.035, c = 5.799 Å, β = 103.7°) [21]. The coordination of Ga atoms for the structure of these polytypes is shown in the Fig. 4. During the cooling this structure is changed substantially. Part of the Ga atoms change their coordination from octahedral up to tetrahedral. The latter requires shift of part of the atoms in space. This one may lead to lost of the long range order in the structure, I,e, to formation of the glass phases. The correspond tetrahedral

3. Experimental 3.1. Sample preparation

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and octahedral may be a source of the second order optical effects.

(1-x)TeO2-xGa2O3 glasses with 5 ≤ x ≤ 25 (in mole%) were obtained from reagent grades α-

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TeO2 and β-Ga2O3 thoroughly mixed in the required composition. For samples with x=5, 10, and 15 composition, the 1gmixtures were melted in Pt cruciblesat 900°C in air for 30 min then quenched in

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an ice-cold water bath. The obtained bulk glasses were transparent and presented an orange-brown color. In order to extend the glass forming domain of the TeO2-Ga2O3 system, an ultra-fast quenching method using the twin-roller technique was also used [22]. In this case, 500 mg of the mixture was melted at 1000°C in a Pt crucible under Ar atmosphere then immediately ultrafastquenched to avoid evaporation of the product.Thin glassy samples (thickness approx. of 50 µm) of x=20 and x=25 composition were obtained. The amorphous state of all the samples was checked by room temperature X-ray diffraction using Cu-Kα radiation. The samples were not annealed.

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ACCEPTED MANUSCRIPT 3.2. Experimental details The main idea of this publication consists of using the photoinduced light to obtain optically operated piezo-optic coefficients. The experimental setup for the measurement of the photoinduced POE (piezo-optic effect) constants are presented in the fig. 5. The measurement set-up had two

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channels: photoinduced/pumping (solid red line) and probing (dashed red line) ones. To achieve maximal POE changes we have applied bicolor coherent light originating from pulsed laser based on erbium-doped oxide glasses or fundamental nanosecond Nd:YAG (yttrium aluminum garnet) pulsed laser. The photo-pumping was performed by nanosecond pulses of λ =1540 nm Er: glass laser with a pulse duration 25 ns, pulse repetition frequency of 10 Hz and power densities varying within 50-

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800 GW/cm2. The optical second harmonics were generated by a single phase-matched a-BiBO non-linear crystal cut under phase matching conditions [23]. The set of mirrors from 1 to 3 and

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filters F1, F2 was used for the spectral separation of the doubled frequency (orange line) and fundamental (red line) laser beams. After the separation of those two beams, they (seeding) were overlapped on the samples surface.

Phenomenologically, the piezo-optic effect may be described by the fourth rank polar tensor πijkl and is related with the birefringence ∆nij by the equation given below: (1)

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∆nij = π ijkl ⋅ σ kl

, where ∆nij is birefringence; σkl – is mechanical stress tensor;

πijkl – piezooptical tensor

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As a probing laser for registration of piezo-optic birefringence (applied in the traditional Senarmont scheme) was used He-Ne laser with wavelength of 1150 nm and power about 15 mW.

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Generally the intensity of the transmitted light is described by:

 ∆nij ⋅ leff  I = I 0 sin 2    λ 

(2)

where I and I0 are light intensities for the passed and incident light intensities, respectively; leff is an efficient thickness of the sample varied during its rotation around the axes; λ-wavelength. As a photodetector measured the changes of the light intensity versus the applied mechanical stress was used Si photodiode. During the application of the mechanical stress the intensity of the propagated light and analyzer monitored the occurred phase difference of the photo-optic birefringence under

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ACCEPTED MANUSCRIPT the applied mechanical stress. The analyzer and λ/4 phase invertor was used to the determine the output intensity. The sample orientations were done following the standard Senarmont procedure. The piezo-optic coefficient was determined from the birefringence using the Senarmont

π ijkl =

λ I ⋅ arcsin leff σ kl I0

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method as given below: (3)

The precision of birefringence determination was equal to about 10-6. It is necessary to add that maximal effect was observed for the ratio of fundamental to writing beam of about 6:1. Optimal

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delaying time for the fundamental to writing beam was equal to about 800 ps. It was established that maximal effect was achieved for the off-diagonal tensor components πxxyy. For the diagonal

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components this effect was at least one order less.

4. Results and discussion

The dependences of the piezo-optic coefficient at 1150 nm during the bicolor coherent laser treatment at 1540 nm/770 nm for different content of the TeO2 tellurite glasses and ultra-fast quenching are shown in the Fig. 6. Following the presented figure one can clearly see that during

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the successive enhancement of the bicolor power density up to 400…500 MW/cm2 there is observed an occurrence of some maxima in the piezooptical coefficients behaviors. For the tellurite glasses without ultra fast quenching one can observe an increase of the πxxyy which does not exceed 8.0×1014

m2/N. The maximal increase is observed only for of two samples which have been ultra fast

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quenched. The corresponding POE maxima are shifted toward higher power density (from 400 to 500 GW/cm2) with respect to samples without ultra fast quenching. Additionally the increasing

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content of the TeO2 also favors the observed effect. It was established that the maximum of the POE tensor coefficient magnitude achieves its maximal value of 14.0×10-14 m2/N at power density about 500 MW/cm2 for the ultra fast quenching samples with the highest content of the TeO2 equal to 80. With the further increase of the laser treatment one can see some decrease of the piezo-optical coefficient. This fact may confirm an assumption that the TeO2 plays where crucial role. The increase in the value of the photoinduced POE non-diagonal coefficients depends not only on the content of the TeO2 but also on the applied optical treatment. To confirm this thesis we have been carried out measurements of this coefficient during the excitations by the 1064 nm/532 nm coherent bicolor beams what is presented in the figure 7. The overlap between the photoinduced 5

ACCEPTED MANUSCRIPT and probing beam was about 95 %. Like the previously we have obtained highest piezo-optic coefficient value equal to about 12×10-14 m2/N for samples with the largest content of TeO2 and at power density equal to about 450 nm. Additionally there is also obvious that there is no significant difference between 80 and 75 TeO2 content. Both of them have the same maximum at the same power density. In this case it was also observed decrease of the piezo-optic coefficient with the

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increase of the photoinduced laser treatment above 450 GW/cm2. However, this coefficient not falls below 12% relative to its maximum value. It is important to add that the changes of the piezooptical coefficient were observed only for the ultra-fast quenched samples. So one can conclude that the changes of photoinduced POE coefficients may be also very sensitive to the optical treatment

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investigated glasses.

The decay of the piezoopotical non-diagonal tensor components after the switching off of the

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photoinduced laser beams show (see Fig. 8) that the PEO coefficient is completely decrease up to the initial value after the times more than 100 ms. The obtained results demonstrate a principal role of the electron-phonon anharmonic interactions in the considered fourth order piezo-optical tensor. It is a consequence of induced phonon effectively interacting with external laser beam. To understand the origin of the effect we have performed quantum chemical calculations for the different local structural fragments under influence of the external laser fields. They were

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performed by DFT method using the approach similar to the described in the reference [24]. We have performed the calculations for all the principal structural fragments presented in the Fig. 1-4. Following the performed calculations it was appeared that principal ground state dipole moment of the such kind of glasses are determined by Ge-O4 possessing ground state dipole

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moemtns about 6 D and for other cluster the corresponding values were below 3 D. For illustration

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their space charge density distribution is shown in the Fig. 9.

The obtained by us parameters are better than the values of the photoinduced piezooptics obtained in the other glasses [25-28]. However, following their structure they are alsa promising for the incorporation of the rare earths favoring excellent fluorescence and photoinduced properties [2930].

4. Conclusions

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ACCEPTED MANUSCRIPT It was shown a drastic increase of the piezo-optical non-diagonal coefficients at 1150 nm wavelength during the treatment by the bicolor coherent 1064nm/532nm and 1540 nm/770 nm pulse laser beams. During the successive enhancement of the bicolor power density up to 400…500 MW/cm2 there is observed an occurrence of some maxima in the piezo-optical coefficients

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behaviors. The maximal increase is observed for ultra fast quenching samples. Additionally the increasing content of the TeO2 also favors the observed effect. With the further increase of the laser treatment one can see some decrease of the piezo-optical coefficient. This fact may confirm an

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assumption that the TeO2 plays where crucial role.

References

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[1] S. Azeemuddin, M.R. Sayeh. Effect of various parameters on working of all-optical Schmitt trigger, Optik 122 (2011)1935-1938.

[2] J.K Hmood, S.D. Emami, K.A. Noordin, H. Ahmad, S.W. Harun, H.M.H. Shalaby, Optical frequency comb generation based on chirping of Mach–Zehnder Modulators, Opt. Commun. 344 (2015) 139-146.

[3] J. Marthe, E. Meillot, G. Jeandel, F. Enguehard, J. Ilavsky, Enhancement of scattering and

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reflectance properties of plasma-sprayed alumina coatings by controlling the porosity. Surf. Coat. Technol. 220 (2013) 80-84.

[4] T. Srikumar, I.V. Kityk, Ch. Srinivasa Rao, Y. Gandhi, M. Piasecki, P. Bragiel, V. Ravi Kumar, N. Veeraiah, Photostimulated optical effects and some related features of CuO mixed

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Li2O–Nb2O5–ZrO2–SiO2 glass ceramics. Ceram. Int. 37 (2011) 2763-2779. [5] H. Eklund, A. Roos, S. T. Eng, Rotation of laser beam polarization in acousto-optic devices.

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Opt. Quant. Electron. 7 (1975) 73–79. [6] A. Christofi, N. Stefanou, Nonreciprocal guided modes in photonic crystals of magnetic garnet particles with a planar defect. JOSA B, 31 (2014) 2104-2108. [7] T.M. Williams, D. Hunter, A.K. Pradhan, I.V. Kityk. Photoinduced piezo-optical effect in Er doped ZnO films, Appl. Phys. Lett. 89 (2006) 043116. [8] L.R.P. Kassab, M.E. Camilo, Ali H. Reshak, K.J. Plucinski, Photoinduced piezooptical changes caused by microsecond CO2 Infrared lasers in lead-germanate rare earth tri doped glasses, Mater. Lett. 65 (2011) 1445-1447.

7

ACCEPTED MANUSCRIPT [9] S. Tkaczyk, M.Galceran, S. Kret, M.C. Pujol, M. Aguilo, F. Diaz, A.H. Reshak, I.V. Kityk, UV-excited piezooptical effects in oxide nanocrystals incorporated into PMMA matrices, Acta Mater. 56, (2008) 5677–5684. [10] M.K. Balakirev, V.A. Smirnov, L.I. Vostrikova, I.V. Kityk, J. Kasperczyk, W. Gruhn, Giant

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increase of the second harmonic radiation’s absorption during optical poling of oxide glass, J. Mod. Optic. 50, (2003) 1237-1244.

[11] M. Dutreilh-Colas, P. Charton, P. Thomas, P. Armand, P. Marcheta, J.C. Champarnaud Mesjarda, The TeO2- rich part of the TeO2–Ga2O3 system: equilibrium and non-equilibrium phase diagram, J. Mater. Chem. 12 (2002) 2803-2806.

J. Non-Cryst. Solids 333 (2004) 307–315.

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[12] P. Charton, P. Armand, X-ray absorption and Raman characterizations of TeO2–Ga2O3 glasses,

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[13] D. Ilieva, V. Dimitrov, Y. Dimitriev, G. Bogachev, V. Krastev, Structural study on Ga2O3– TeO2 glasses, Phys. Chem. Glasses 39 (1998) 241-245.

[14] P.A. Thomas, The crystal structure and absolute optical chirality of paratellurite: α-TeO2, J. Phys. C: Solid State Phys. 21 (1988) 4611-4627.

[15] H. Beyer, Verfeinerung der Kristallstruktur von Tellurit, dem rhombischen TeO2, Z. Kristallogr. 124 (1967) 228-237.

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[16] J.C. Champarnaud-Mesjard, S. Blanchandin, P. Thomas, A. Mirgorodsky, T. Merle-Méjean, B. Frit, Crystal structure, Raman spectrum and lattice dynamics of a new metastable form of tellurium dioxide: γ-TeO2, J. Phys. Chem. Solids 61 (2000) 1499-1507. [17] J. Emsley, The elements, Oxford Univ. Press, New York, 1997.

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[18] M. Dutreilh, P. Thomas, J.C. Champarnaud-Mesjard, B. Frit, Crystal structure of a new gallium tellurite: Ga2Te4O11, Solid State Sci. 3 (2001) 423-431.

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[19] M. Yamaguchi, M. Ishikawa, Magnetic phase transitions in inverse trirutile-type compounds, J. Phys. Soc. Jpn. 63 (1994) 1666-1669. [20] T. Tsuchiya, H. Yusa, J. Tsuchiya, Post-Rh2O3(II) transition and the high pressure-temperature phase diagram of gallia: a first-principles and X-ray diffraction study, Phys. Rev. B: Condens. Matter 76 (2007) 174108-1. [21] V. M. Bermudez, The structure of low-index surfaces of β-Ga2O3, Chem. Phys. 323 (2006) 193-203. [22] J.-C. Sabadel, P. Armand, D. Cachau-Herreillat, P. Baldeck, O. Doclot, A. Ibanez, E. Philippot, Structural and nonlinear optical characterizations of tellurium oxide-based glasses: TeO2-BaOTiO2, J. Solid State Chem. 132 (1997) 411-419. 8

ACCEPTED MANUSCRIPT [23] V. Petrov, M. Ghotbi, O. Kokabee, A. Esteban-Martin, F. Noack, A. Gaydardzhiev, I. Nikolov, P. Tzankov, I. Buchvarov, K. Miyata, A. Majchrowski, I.V. Kityk, F. Rotermund, E. Michalski, M. Ebrahim-Zadeh, Femtosecond nonlinear frequency conversion based on BiB3O6, Laser Photonics Rev. 4 (2010) 53-98.

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[24] I.V.Kityk, M.Demianiuk,A.Majchrowski,J.Ebothe,P.Siemion. IR-induced second-harmonic generation in PbSe microcrystallites. J.Phys.:Condens.Mater. 16, (2004), pp.3533-3544. [25] L.R.P. Kassab, K.J. Plucinski, M. Piasecki, K. Nouneh, I.V. Kityk, A.H. Reshak, R. de A Pinto. Photoinduced piezooptics in PbO-GeO2 glasses, Optics Communications 281 (2008)

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3721–3725

[26] L. R. P. Kassab, T. A. A. de Assumpção, P. Czaja, E. Gondek, K. J. Plucinski. PbO–

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GeO2 rare earth doped glasses with silver nanoparticles as materials for IR laser triggers. Journal Materials Science :Mater. Electronics, 23, (2012), 1122-1125 [27] J.Kasperczyk, E.Golis, J. Wasylak, Nonlinear optical properties of lead-bismuth-gallium glasses. Mater.Research Bulletin, 31, (1996), . 1057-1065.

[28] I.V.Kityk, E.Golis, J.Filipecki, J.Wasylak, V.M.Zacharko. Photoinduced nonlinear optical

1293.

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phenomena in PbO-BiO1.5-GaO1.5 glass. Journal of Material Science Letters. 14. (1995). 1292-

[29] I.V.Kityk, J.Wasylak, J.Dorosz, J.Kucharski Eu3+-doped glass materials for red luminescence. Optics & Lasers 33, (2001), 157-160.

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[30] A.Majchrowski, M.Swirkowicz, K.Ozga. Optical operation by elastooptical dispersion

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of Nd-containing oxide crystals. Optics communications, 283, (2010), 1378-180.

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Fig. 1. Principal package of polyhedral and inter-atomic distances for Te-O in the structure α-TeO2,

β-TeO2 and γ-TeO2. 10

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Fig. 2. Coordination of Te ions for Ga2Te4O11.

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Fig. 3. The local coordination of the Te in the Ga2TeO6 (Ga – blue sphere).

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Fig. 4. The polyhedral package and inter-atomic distances for Ga-O chemical bonds for the structure

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α-Ga2O3 and β-Ga2O3.

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las s

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He-Ne laser

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Photodetector Analyzer

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Fig. 5. Experimental set-up for measurement of the piezo-optic effect.

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1 2 3 4 5

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Fig. 6. Dependence of the piezo-optical coefficient at 1150 nm during the bicolor coherent at 1540

nm/770 nm bicolor laser treatment for: 1 – 85TeO2-15Ga2O3; 2 – 90TeO2-10Ga2O3; 3 – 95TeO2-

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5Ga2O3; 4 – 75TeO2-25Ga2O3 (ultra-fast quenching); 5 – 80TeO2-20Ga2O3 (ultra-fast quenching).

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80TeO2-20Ga2O3

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75TeO2-25Ga2O3

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Fig. 7. Photoinduced dependence of the piezo-optical coefficient at 1150 nm versus the bicolor

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photoinduced treatment at 1064 nm/532 nm.

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pumping laser beams.

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Fig. 8. Typical decay of the piezo-optical constant after the switching off of the photoinduced

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Fig. 9. The charge density distribution for the Ga1-O structural fragments: a) without the laser treatment; b) under applied external laser treatment at ab0ut 600 MW/cm2. The increment of the isoelecron line is equal to about 0.2 e/Ω.

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ACCEPTED MANUSCRIPT >The photoinduced changes in the TeO2-Ga2O3 glasses were found with respect to

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piezooptical effects. >The maximal contribution give the Ga-O4 structural fragments.> The effects disappears after the switching off of the illumination.