kevin bourhis jean-jacques videau, mona treguer, thierry cardinal (icmcb-cnrs) arnaud royon, lionel...
TRANSCRIPT
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