Kevin Bourhis

Jean-Jacques Videau, Mona Treguer, Thierry Cardinal (ICMCB-CNRS)

Arnaud Royon, Lionel Canioni (CPMOH-CNRS)

Workshop LasINOF, June 14th 2010

• Interaction between short-pulsed lasers and silver-containing glasses micro- and nanostructuring in 3D can be achieved

• Glass modification visible under UV (325 nm) or blue light (405 nm)• Stability of the photo-induced structures variable(composition, irradiation conditions…)

Examples of stability of photo-induced structuring with femtosecond lasers

Femtosecond laser irradiation = silver reduction + heat treatment

What affects the stability ? - silver content - the glassy matrix

- the irradiation conditions

1.Silver and gallium introduction

2.Nature and modifications of the glassy matrix

3.Influence of the irradiation conditions

4.Conclusion

Red shift of the absorption cut-off (5d10 4d9 5s1 dipolar transition Ag+ ion) with

increasing Ag/Ga

0 1 2 3 4

0

1

2

3

4

Ag

/ Ga

ratio

mol% (Ag2O)

1 to 4 mol%(Ag2O) = [Ag/Ga] x 16

55ZnO-4OP2O5

• Good system for Ag+ introduction• Hygroscopic glass addition of Ga (reticulation) , conservation of

P/Zn ratioGlass composition studied : 55 ZnO – 40 P2O5 – (5-x) Ag2O – x

Ga2O3, x ?

225 250 275 300 325 3500

5

10

15

20

25

30

Abs

orpt

ion

coef

ficie

nt (

cm-1)

Wavelength (nm)

Ag/Ga ratio 0 1/4 2/3 4

IR-fs structures µm3 UV-ns structures = near-band gap, larger areas

PHOTOSENSITIVE AGENT

Ag+ ion

Photoreduction (photographic process)

Formation of Agmx+ clusters

Luminescent probe Agmx+

clusters

300 350 400 450 500 550 6000

1

2

3

4

5

6

7

Ab

sorp

tion

co

effi

cie

nt (

cm-1)

Wavelength (nm)

Pristine glass 30min 10min 1min

Irradiation at laser = 355 nm

Growth of absorption bands

@ 320 nm@ 380 nm

New Agmx+ species are

formed during the irradiation

Luminescence spectra = evidences of modifications

Red shift of the excitation band ( 15 nm) with Ag/Ga

220 240 260 280 3003200,0

0,2

0,4

0,6

0,8

1,0

exc = 250 nm

Nor

mal

ized

inte

nsity

Wavelength (nm)

em

= 350 nm

300 400 500 6000,0

0,2

0,4

0,6

0,8

1,0

Ag/Ga = 1/4 Ag/Ga = 4

Nor

mal

ized

inte

nsity

Wavelength (nm)

Ag/GaNumber of sites

max (nm)

1/4 2290 ; 385

4 1 385

Modification of the glassy networkNeighboring of the non-bridging O linked with P or Ga to be

investigated

55ZnO-40P2O5

Majority of Q2 and Q1 sites(1 or 2 NBO)

Qn, n = number of bridging O

600 650 700 750 800 850 900

750 cm-1

Re

lativ

e in

ten

sity

(a

.u.)

Wavenumber (cm-1)

Ag/Ga ratio 0 1/4 2/3 4

705 cm-1

s & as(P-O-P), Q2 & Q1

705 cm-1 = (P-O-P) of Q2

750 cm-1 = (P-O-P) of Q1

Ag/Ga decreases Q1/Q2 increases

Hypothesis :Ag+ localized on Q1 sites (chains

end)Number of Q1 stable

Ga addtion depolymerisation of Q2 sites

Q2 + Ga2O3 2Q1

Q2 = [PO4] polyhedra (long chain)Q1 = [PO4] terminal tetrahedra

Emission @ exc = 250 nmEmission @ exc = 325 nm; excitation @ 600 nm

For both glasses, decrease of the « Ag+ » 365 nm band

Ag-poor glass : no effect on the 280 nm band

After irradiation, same spectra obtained

300 400 500 600 7000,0

0,2

0,4

0,6

0,8

1,0

Ag/Ga = 1/4 Ag/Ga = 4

exc

= 325 nm

Nor

mal

ized

inte

nsity

Wavelength (nm)

em

= 600 nm

300 400 5000,0

0,2

0,4

0,6

0,8

1,0Ag/Ga ratio

1/4 4

irradiated

irradiated

Nor

mal

ized

inte

nsity

Wavelength (nm)

exc

= 250 nm

Useless to lower the Ag/Ga ratio (2 sites, 1 ineffective, similar emission results)

Agmx+ spectra « Isolated » Ag+ spectra

0 5 10 15 20 25 300

100

200

300

400

500

600

Inte

grat

ed a

rea

(a.u

.)

Time (min)

Saturation phenomenon, similar to photographic process

Consumption of the silver ions pool ?

300 350 400 450 500 5500

1

2

3

4

Abs

orpt

ion

coef

ficie

nt (

cm-1)

Wavelength (nm)

Pristine glass 30min 7min

Ag+ + h Ag0

Ag+ + Ag0 Ag2+

Ag2+ + Ag+ Ag3

2+… Agmx+

EPR : collaboration with D. Caurant & L. Binet (ENSCP, Paris)

2,8 2,7 2,6 2,5 2,4 2,3 2,2 2,1 2,0 1,9 1,8 1,7 1,6-50

-40

-30

-20

-10

0

Inte

nsity

(a.

u.)

g-factor

1h 2h

Ag2+ paramagnetic centers identifiedgortho = 2.307g // = 2.072

Triangular Ag32+ signature ?

giso = 2.003

2,02 2,01 2,00 1,99 1,98 1,97 1,96

-20

-15

-10

Inte

nsity

(a.

u.)

g-factor

ns1h

Seems to be a good tool for determining the Agmx+

paramagnetic speciesConcentration of species relatively low, behavior of this

species with T ?

450 500 550 600 650 7000,0

0,2

0,4

0,6

0,8

1,0

Nor

mal

ized

inte

nsity

Wavelength (nm)

ns fs low dosage fs high dosage

exc

= 405 nm

Heat treatment :

Elimination of the 380 nm excitation band

Blue shifting of the emission

250 300 350 4004500,0

0,2

0,4

0,6

0,8

1,0

exc = 325 nm

Nor

mal

ized

inte

nsity

Wavelength (nm)

em

= 600 nm

400 500 600 7008000,0

0,2

0,4

0,6

0,8

1,0

ns ns heat treated

Nor

mal

ized

inte

nsity

Wavelength (nm)

Low dosage with fs laser similar to ns : no heat accumulation effect

High dosage with fs laser : blue shifting of the luminescence to

orangeControlling the dose and

the temperature tailoring of the luminescence

• Effects of the silver introduction investigated : characterization of 2 luminescent sites

• Effect of the gallium on the glass network discussed : Depolymerization of the network while increasing the gallium content

• Comparisons with thermally treated and fs irradiated samples done : fs irradiation = combination of athermal processes and temperature