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Worshop : LasINOF, June 14th 2010 Aurélien Delestre, E. Fargin, M. Lahaye (ICMCB, Bordeaux, France) V. Rodriguez, F. Adamietz, M. Dussauze (ISM, Bordeaux,

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Présentation au sujet: "Worshop : LasINOF, June 14th 2010 Aurélien Delestre, E. Fargin, M. Lahaye (ICMCB, Bordeaux, France) V. Rodriguez, F. Adamietz, M. Dussauze (ISM, Bordeaux,"— Transcription de la présentation:

1 Worshop : LasINOF, June 14th 2010 Aurélien Delestre, E. Fargin, M. Lahaye (ICMCB, Bordeaux, France) V. Rodriguez, F. Adamietz, M. Dussauze (ISM, Bordeaux, France) M.Bellec, A. Royon, L.Canioni (CPMOH, Bordeaux, France) PATTERNED SECOND HARMONIC GENERATION ON OXIDE GLASSES SURFACE BY THERMAL POLING

2 Outline I / Thermal poling and Second Harmonic Generation (SHG) II / Silver injection by thermal poling and SHG - Samples elaboration and preparation for silver injection - poling voltage and SHG efficiency - Results and interpretation III / Efficient structuring of SHG - Laser ablation, poling - µSHG patterning measurements - Results and interpretation 02 /15

3 Thermal poling for Internal field engraving 03 / 15 Anode Cathode A i ~ 0.5 mA U = 1kV 230°C G Negatively charged depletion zone Na + cations depletion zone creation (L=3-15 µm) Mobile cations can migrate from anode to cathode ------ - --- - - - - - E int ------- Embedded internal field induces Second Harmonic Generation in Glasses Glasses are centro-symmetric materials  (2) =0

4 Composition : sodium and niobium borophosphate glasses (BPN42) (1-x)[0,95NaPO 3 +0,05Na 2 B 4 O 7 ]+xNb 2 O 5 x = 0,42 Silver injection by poling : Silver layer deposition on the glass surface Glass samples elaboration + silver injection 04 / 15 Metallic silver film Glass SHG modified ? Why silver ? Na + and Ag + : Comparable diffusion coefficients in oxide glasses Structuration of silver electrode SHG structuration ~ 5 mm Poled surface after poling Zone outside the anode Zone under the anode *Référence : M. Dussauze Optics Express, Vol. 13, Issue 11, pp. 4064-4069 Thermal Poling induces - departure of sodium ions - injection of silver ions

5 Observation : Efficient poling leads to  (2) comparable to the reference Efficient polingNon efficientEfficient poling Sample Reference no AgAg Silver thin film thickness (nm) e ±10 nm 0200220170240300   2) (pm/V) ± 10 -2 1.06001.201.000.96 Nonlinear zone thickness (µm) L ± 0.1 µm 3.0--2.93.83.0  (2) values deduced from Maker Fringes simulations 05 / 15 Why poling is efficient? Why poling can be inefficient? Thermal poling 230 °C, t = 1 h, U ~ 1 kV, i 0 = 0.5 mA (sample thickness 1 mm)

6 Sodium depletion zone: 3 µm thickness Space charge zone identical to SHG efficient zone *Reference : M. Dussauze Optics Express, Vol. 13, Issue 11, pp. 4064-4069 Reference Without Ag Na, Nb, P atomic concentration profiles Cathode Anode Poled zone Quantitative X-ray analysis on the reference 06 / 15

7 Cations migrations : - Na + ions depletion (6 µm) - Ag + ions penetration (6 µm) Quantitative X-ray analysis 07 / 15 Sample efficient polingWith Ag Ag thickness(nm) ±10 nm170  (  2) (pm/V) ± 10 -2 1.20 Nonlinear zone thickness (µm) ± 10 -1 2.9 SHG profile correlated to total cations depletion - between 2.9 µm and 6 µm Ag substitutes to Na Efficient poling with Ag - the nonlinear zone producing SHG is located between 0 to 2.9 µm under the surface efficient SHG zone Na depletion zone Ag injection zone 2.9 0246810121416 0 2 4 6 8 10 12 14 16 18 20 % Atomic Depth under the anode surface (µm) Na Ag P Nb Atomic concentration profiles under the anode

8 Cations migration : - Na + depletion ( 2 µm) - Ag + injection ( 2 µm) *reference : E. Fargin Advanced Materials Research Vols. 39-40 (2008) pp 237-242 déplétion zone Quantitative X-ray analysis 08 / 15 Inefficient poling with Ag Ag + injection compensates Na + depletion No SHG 024681012 0 2 4 6 8 10 12 14 16 % Atomic Depth under the anode surface (µm) Na Ag P Nb Atomic concentration profiles No space charge zone creation Poling voltage ~1 kV is the minimum to develop efficient poling

9 Influence of voltage on poling efficiency First polings mistake : special attention on the current Now big care on the voltage !!! Thermal poling 230 °C, t = 1 h, U = different voltage, i 0 < 0.6 mA (sample thickness 500µm) SHG efficiency is linked with poling tension 09 / 15

10 SHG architecture Surface profile image of ablated lines BPN42 + Ag thin film deposition Laser Ablation of silver lines (Length = 3 mm, width = 2 µm) Thermal poling 230 °C, t = 1 h, U = 1 kV, i 0 < 0.6 mA laser Yb : Wavelength = 1030 nm pulse duration= 470 fs Repetition rate = 10 MHz Mean power = 6 W Laser fs IR AOM Laser fs IR AOM Laser fs IR AOM Laser fs IR AOM Laser fs IR AOM Laser fs IR AOM Ag thin film Ablated line 100µ m 10 / 15 Image of ablated lines (optical microscopy)

11 µSHG Analysis 40 -30 -20 -10 0 10 20 30 -40-20 20 0 Y (µm) X (µm) Ag Ablated Poled lines Ag Non ablated poled zone 2ω ( polarization of reflected SHG field ) ω (polarization of incident beam field) µGSH allows different fields orientations Different components in Exemple : YXX Ablated lines 11/ 15

12 XXX polarization  SHG signal analysis on the surface SHG signal is very intense on the lines non ablated zone Intensité (u.a.) Nombre d’onde (cm -1 ) Ablated zone : 600 500 400 300 200 100 0 -50005001000 Analysis Incident Surface 3 µm under the surface Z=0 Z=1 Z=2 Z=3 Z=4 3D mapping: 12 / 15 Wavenumber (cm -1 ) Intensité (u.a.) 14 12 10 8 6 4 2 0 -50005001000 Nombre d’onde (cm-1) Flight intensity  xxx (2)  0

13 SHG signal for different pump and probe polarizations New Symmetry induced by poling 13 / 15 Usual symmetry obtained by poling C ∞v ------ - --- - - - - - E int            00 0000 00 )2( zzxzzzzyyzxx yyxyyz xxzxzzxyyxxx  Cs (symmetry plane: xz) *reference : A. Delestre, Applied Physics Letters, volume 96, Issue 9, id. 091908(2010)

14 Quantitative analysis of elements under anode Silver concentration mapping 14 / 15 Lifted lines Silver concentration variation through ablated lines Ablated lines Silver layer Silver injection [Ag + ] z x Ionic profile in the non ablated area Ionic profile in the ablated area

15 Conclusion and perspectives 15 / 15 + Silver ions introduction by thermal poling : Silver injection is compatible with SHG Control the applied voltage (threshold for efficiency) + Surface SHG architecture obtained by structured silver deposited electrode: - creation of new symmetry in nonlinear poled surface Objective :

16 Laser ps 532 nm  /2 Prism Glan Taylor Laser ps 1064 nm Power regulation µSHG Setup 11 / 23 M1 Platine XYZ CCD polarization Pine hole /4 M2 M3 M4 M5 M6 M7 NIR Objective Filter 2 Filter Notch 1064 ou 532nm Advantages : - Mapping (platine XYZ + CCD) - Résolution ~ 1 µm (Objective NIR 100X, ON = 0,5) - Simultaneous µRaman spectroscopy Sample

17 Présence de signal GSH dans la zone polée Pas de variation de signal GSH dans la zone ablatée Polarisation YXX 40 -30 -20 -10 0 10 20 30 -40-20 20 0 Y (µm) X (µm) Analyse Incident 1 µm -5 0 5 10 X (µm) -4-2024 Y (µm) 1.5 1.0 0.5 0.0 Pas de contraste de signal GSH Signal GSH dans/hors des lignes ablatées 24 / 30 Intensité (u.a.) Nombre d’onde (cm -1 )

18 5 µm -30 -20 -10 0 10 20 30 Y (µm) -40-2002040 X (µm) Echantillon tourné de 90° Analyse Incident Y (µm) X (µm) Polarisation YYY Signal GSH homogène Pas de contraste de signal GSH 50 40 30 20 10 0 Intensité (a.u.) -50005001000 Nombre d’onde (cm-1) Zone ablatée XYY Signal GSH dans/hors des lignes ablatées 25 / 30 1 µm -5 0 5 10 Y (µm) -5 0 X (µm) 4 3 2 1 0 5 Polarisation XYY Variation de signal GSH 5 4 3 2 1 0 Intensité (u.a.) -50005001000 Nombre d’onde (cm-1) Zone non ablatée XYY

19 500 400 300 200 100 0 Intensité (u.a.) 520530540550560 Longueur d’onde (nm) Les échantillons sont coupés au travers des lignes d’ablation Polarisation ZZZ Lignes ablatées Zone non linéaire Surface d’analyse Signal GSH sur la tranche de l’échantillon 100 80 60 40 20 0 Intensité (u.a.) 520530540550560 Longueur d’onde (nm) Zone non ablatée XZZZone ablatée XZZ 5 µm -30 -20 -10 0 10 20 30 Z (µm) -40-2002040 X (µm) Analyse Incident 2 µm -4 -2 0 2 4 6 Z (µm) -10-5051015 X (µm) 2000 1500 1000 500 0 2 µm -6 -4 -2 0 2 4 6 Z (µm) -10-5051015 X (µm) 150 100 50 0 Polarisation XZZ ONL perpendiculaire aux lignes d’ablation 26 / 30

20 µSHG on cross section with a 90° sample rotation Polarisation XXX Polarisation ZXX 1 µm -10 0 10 20 X (µm) -50510 Z (µm) 200 150 100 50 0 1 µm -10 0 10 20 X (µm) -50510 Z (µm) 100 80 60 40 20 0

21 Hypothèse L’augmentation de GSH dans les lignes ablatées viendrait d’un champ interne perpendiculaire à ces lignes GSH par polarisation thermique + ablation Variation de la concentration d’argent au travers des lignes ablatées Lignes ablatées Couche d’argent Pénétration d’argent [Ag + ] Champ interne additionnel perpendiculaire aux lignes ablatées Z=0 Polarisation YYY Polarisation YXX Résultats de µGSH 2 µm -6 -4 -2 0 2 4 6 Z (µm) -10-5051015 X (µm) 150 100 50 0 Polarisation d ’ analyse lignes d ’ ablation Variations GSH dans la zone d ’ ablation Polarisation XZZ déplétion Migration des cations depuis l’anode Création d’une zone de déplétion (L=3-15µm) anode Création d’un champ interne GSH par polarisation thermique cathode 28 / 30

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