laser damage resistance of optical components: limitations

Lase r damage res i s t ance o f op t i ca l componen ts : l im i t a t i ons and improvemen t o f damage t h resho ld

Laurent Gal la is Inst i tut Fresnel (Aix-Marsei l le Universi té, CNRS, Ecole Centrale Marsei l le) , Domaine Universi ta i re de St Jérôme, Marsei l le , FRANCE

laurent .ga l la is@fresnel . f r

mailto:[email protected]�

Out l i ne

• Introduct ion • Some resul ts and discussions on l imi tat ions and

improvements for : • Intrinsic damage threshold of optical materials • Defect-induced damage • Damage growth

• Conclusions, perspect ives

I ns t i t u t F resne l

• Research f ie lds: • Photonics, Electromagnetism, Image processing

• Topics: • Biophotonics, image processing, laser material interactions,

medical applications, nanophotonics, numerical simulations, optical coatings, optical instrumentation,…

• People: • 10 groups • Permanent staff: 83 • PhD students: 54 • Post-docs and fixed term contracts : 31

UMR 7249

H I L A S E / H E P Te c h , 5 m a r c h 2 0 1 5

I LM g roup

• Topics: • Experimental and theoretical work to study the physics of laser

material interactions (fs to CW) • Laser damage of optical components for high power

applications • Laser processing

• People: • 5 permanent staff • 1 Engineer • 6 PhD students

Interact ion Laser Mat ière / Laser Mater ia l Interact ions

H I L A S E / H E P Te c h , 5 m a r c h 2 0 1 5

I LM g roup

L . E s c o u b a s – 1 9 9 7 : l o c a l i z e d a b s o r p t i o n a n d l a s e r d a m a g e P. Vo l t o – 1 9 9 8 : l a s e r d a m a g e i n o p t i c a l t h i n f i l m s A . G a t t o – 1 9 9 9 : E v o l u t i o n o f a b s o r b i n g d e f e c t s u n d e r i r r a d i a t i o n L . G a l l a i s – 2 0 0 2 : l a s e r d a m a g e m e t r o l o g y a n d s t a t i s t i c a l m o d e l s A . D u r i n g – 2 0 0 2 : p h o t o t h e r m a l m i c r o s c o p y O . T h o m a s – 2 0 0 4 : n s n o n - l i n e a r e f f e c t s F. B i l l a r d – 2 0 0 5 : f s / p s n o n - l i n e a r e f f e c t s B . B e r t u s s i – 2 0 0 5 : K D P c r y s t a l s H . K r o l – 2 0 0 6 : t h i n f i l m s f o r M i d I R J . C a p o u l a d e – 2 0 0 8 : D a m a g e s t a t i s t i c s i n K D P a n d t h i n f i l m s H . H i l d e n b r a n d – 2 0 0 8 : N o n - l i n e a r c r y s t a l s ( R T P, B B O , . . . ) A . C i a p p o n i – 2 0 0 9 : l u m i n e s c e n c e f o r l a s e r d a m a g e s t u d i e s B . B u s s i è r e – 2 0 0 9 : T i : S a p h i r e c r y s t a l s S . R e y n é – 2 0 11 : m u l t i - w a v e l e n g t h e f f e c t s i n K D P c r y s t a l s B . M a n g o t e – 2 0 11 : s u b - p s l a s e r d a m a g e o f o p t i c a l t h i n f i l m s X . F u – 2 0 1 2 : n s l a s e r d a m a g e r e s i s t a n c e o f b i n a r y o x i d e f i l m s a n d D O E C . G o u l d i e f f – 2 0 1 3 : F a t i g u e e f f e c t s u n d e r n s U V i r r a d i a t i o n M . C h a m b o n n e a u – 2 0 1 4 : m u l t i - w a v e l e n g t h e f f e c t s i n s i l i c a A . H e r v y – e x p 2 0 1 5 : o p t i c a l i n t e r f e r e n c e c o a t i n g s f o r i n t e n s e u l t r a s h o r t p u l s e s D . B . D o u t i – e x p 2 0 1 5 : p h y s i c s o f f s l a s e r d a m a g e i n t h i n f i l m s T. D o u a l l e – e x p 2 0 1 6 : d a m a g e m i t i g a t i o n p r o c e s s e s f o r s i l i c a o p t i c s R . D i a z – e x p 2 0 1 6 : n s d a m a g e p r o c e s s i n t h i c k s i l i c a w i n d o w s M . S o z e t – e x p 2 0 1 7 : m e t r o l o g y a n d i m p r o v e m e n t o f L I D T f o r P W o p t i c s A . B a u d i e r – e x p 2 0 1 7 : F a t i g u e e f f e c t s u n d e r n s D U V i r r a d i a t i o n

Laser damage PhD student topics

I LM g roup

Academics: Agencies: Industry:

Col laborat ions on Laser Damage issues (past and present)

Lase r damage Context

« Laser damage » in title, Web of Science database (medical applications excluded, conferences excluded)

1960 1970 1980 1990 2000 20100

10

20

30

40

50

60

70

80

90

100

Cou

nt

Year

Peer Reviewed Articles

*M. Hercher, “Laser-induced damage in transparent media”, JOSA 54 563 (1964). **C. Giuliano, “Laser-induced damage to transparent dielectric materials”, JOSA 54 1400 (1964).

• Laser damage: • I r revers ib le modi f icat ion of a

mater ia l submi t ted to laser i r rad ia t ion

• Resul t o f the coupl ing of laser l ight wi th mater ia l

• Subject is s tudied s ince the advent of lasers*,**

• Large database and sc ient i f ic work on the subject

• Sti l l a main l imi tat ion • Growing interest wi th the

development of intense lasers

Lase r damage o f op t i ca l componen ts Consequences in h igh power laser chains

High power laser

Very expensive optic


High power laser

Damage Initiation


High power laser

Damage Initiation

Local reduction of damage resistance


High power laser

Damage Initiation


Damage growth


High power laser

Damage Initiation


Damage growth

contamination


High power laser

Damage Initiation


Damage growth

contamination

Integrety of the optical component


High power laser

Damage Initiation


Damage growth

contamination


Beam obscuration


High power laser

Damage Initiation


Damage growth

contamination


Beam obscuration

Scattering Losses


High power laser

Damage Initiation


Damage growth

contamination


Beam obscuration

Scattering Losses

Wavefront modulations

Degradation of beam quality


High power laser

Damage Initiation


Damage growth

contamination


Beam obscuration

Scattering Losses

Wavefront modulations

Degradation of beam quality

Damage propagation

Other expensive optic

Out l i ne




L im i t a t i ons

Basic processes occur at d i fferent t imescales: – Excitation

• Absorption by free electrons in the material – Initial free electrons in metals – Free electrons created by non-linear ionisation in dielectrics

– Energy transfer • From electrons to lattice • Heat diffusion in the material

– Response of the material • Phase change • Hydrodynamic motion, shock waves • Thermo-mechanical stress

– Material removal • Thermal or mechanical effects depending on the deposited energy,

material properties and irradiation conditions

Physics of laser damage under intense i r radiat ion

time

fs

ps

ns

µs

L im i t a t i ons Physics of laser damage

time

fs

ps

ns

µs

fs pulse ns pulse

Laser / plasma

interaction will drive energy

deposition and

damage process

Energy deposition

and damage

processes are

separated in time

Main property: related to defects that can iniate a

plasma

Main property: related to intrinsic

properties of the material

L im i t a t i ons Intr insic exci tat ion processes in d ie lectr ic mater ia ls

Conduction band

Energy

Time

EV

Ec

Eg

PhotoionizationFree carrier-heating

Impact ionization& avalanche

Relaxation, trapping

MPI TI

Valence band

Etc…

Trapson native or Laser-induceddefects

ST

DT

L im i t a t i ons Intr insic damage resistance of opt ical mater ia ls - fs

Improvement of damage resistance?

1 2 3 40.0

0.5

1.0

1.5

2.0

LIDT

(J/c

m²)

Photon energy (eV)

Nb2O5 Simulation Ta2O5 Simulation HfO2 Simulation Sc2O3 Al2O3 Simulation

L. Gallais et al., Submitted.

L. Gallais et al., Appl. Opt. 53 (2014)

1 10 100 1000 10000 1000000.0

0.2

0.4

0.6

0.8

LID

T (J

/cm

²)

Number of pulses

1030nm 515nm 343nm MS IAD

D.B. Douti, Opt. Eng. 53 (2014)

LIDT vs Bandgap LIDT vs photon energy LIDT vs Number of pulses

1on1, 800nm, 100fs 1on1, 310-1200nm, 100fs Nb2O5 film, Son1, 1030/515/343nm, 500fs

1 2 3 4 5 6 7 8 9 10 110.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

Si Simulation Ge Nb2O5

Ta2O5

HfO2

Sc2O3

Al2O3

SiO2 (film) SiO2 (bulk) CaF2

LIDT

(J/c

m²)

Bandgap (eV)

Imp rovemen t mater ia ls

1,4 1,6 1,8 2,0 2,2 2,40

1

2

3

4

5

6

SiO2 Nb2O5/SiO2 Nb2O5 ZrO2 ZrO2/SiO2 Ta2O5 Ta2O5/SiO2 HfO2 HfO2/SiO2 Al2O3 Al2O3/SiO2 Sc2O3 Sc2O3/SiO2 Al2O3/AlF3 AlF3 Y2O3 TiO2

Thre

shol

d (J

/cm

²)

refractive index

A. Melninkaitis et al., Appl. Opt. 50 (2011). Mangote et al., Opt. Lett. 37(2012).

M. Mende et al., Appl. Opt. 52 (2013).

Mixture materials: • With an adapted design, the use of mixture materials can lead to subsequent enhancement of the LIDT of multilayer systems compared to the use of pure material systems

Imp rovemen t

The design can be opt imized to improved the damage threshold:

• Reduce E- f ie ld in the ‘weak ’ layer (non-quar ter wave s tacks)

• Remove in ter faces (Rugate f i l ters) • Inser t grad ients • Combine mater ia l wi th d i f ferent

proper t ies (d ie lec t r ics , meta ls) • Reduce s t ress • Protect ion, adhes ion layers • Manage thermal issues • …

Case of opt ical Inter ference coat ings: Designs

To be discuss by A. Hervy…

0,0

0,5

1,0

1,5

|E/E

inc|²

Imp rovemen t Case of fs regime

• Comparat ive study R-max (99,5%) at 800nm, tes ted at 200 fs :

C.J. Stolz et al., « Thin Film Femtosecond Laser Damage Competition », Laser Damage Symposium, 2010

Imp rovemen t Case of ns regime

• Comparat ive study R-max (99,5%) à 1064nm tested at 5ns :

C.J. Stolz et al., « Thin Film nanosecond Laser Damage Competition », Laser Damage Symposium, 2009

Out l i ne




L im i t a t i on : de fec t i n i t i a t ed damage

Main mechanism=absorpt ion delocal isat ion: • Defect= seed for the damage process • Af ter reaching a cr i t ica l temperature, severa l processes

can lead to the extens ion of an absorpt ion f ront

Physics of ns defect in i t ia ted damage

e- hν T>Tcrit.

Grua et al., Phys. Rev B,2003 Danileiko et al., Sov. J. Quant. Elec., 1978 Saito et al., Phys. Rev B,2000 Bude et al., Laser damage symposium 2007

A nanometric defect can lead to significant absorption of laser energy

L im i t a t i on : de fec t i n i t i a t ed damage Physics of ns defect in i t ia ted damage

A nanometric defect can lead to a macroscopic damage

Simulations of energy deposition, shock wave and fracture propagation with hydrodynamic codes. Defect is a gold inclusion in a silica martix. 6J/cm², 355nm, 3ns

F. Bonneau et al., Appl. Phys. B,2004

surface

volume

L im i t a t i on : de fec t i n i t i a t ed damage Examples of defects

J. Fournier et al, Opt. Express 18 (2010).

J. Bude et al, Opt. Express 22 (2014).

S. Demos et al, Opt. Lett .26 (2001).

Surface contamination

Fractures Clusters of electronic

defects

Many others!

160µm

Imp rovemen t : de fec t m i t i ga t i on Local mel t ing/anneal ing

P. Cormont et al, Opt. Express 21 (2013). P. Cormont et al, Advanced Engineering materials (2014).

Application on an optic representative of LMJ production:

Polishing scratch

CO2 Laser•CO2laser is an interesting tool to remove scratches because it can melt efficiently the silica in a rapid and localized way, without generating debris •Can be applied between polishing and finishing

3ns, 355nm

Imp rovemen t : de fec t m i t i ga t i on Anneal ing

15 16 17 18 19 20 21 22 23

0

20

40

60

80

100

Sample 1 Initial Annealed

Sample2 Initial Annealed

Dam

age

prob

abili

ty (%

)

Fluence (J/cm²)N. Shen et al. et al., Opt. Eng. 51 (2012)

T. Doualle et al. et al., Submitted

One widely applied method of removing point defects in silica is to isothermally anneal the material in a furnace.

Application on polished fused silica substrates (3ns, 355nm):

Imp rovemen t : de fec t m i t i ga t i on Laser condi t ioning

M. Commandré et al., Eur. Phys. J. 153 (2008)

Annihilation and/or passivation of defects can be observed, depending on fluence and exposure time => conditioning process

Absorption evolution of an isolated defect (250nm gold particle in a silica matrix) under successive ns exposures at 1064nm (no surface modification)

Out l i ne




L im i t a t i on : Lase r damage g row th Analyse of damage s i tes

18 µm 50 µm

9,5 µm Crack zone

Damage zone

M.A Norton et al. Proc SPIE 6403 (2006) J. Wong et al. J. Non Cryst. Sol. 352 (2006)

B. Bertussi et al. Opt. Express 17 (2009)

UV, ns, rear face, damage site on silica surface

L im i t a t i on : Lase r damage g row th Growth laws

L. Lamaignère et al., Appl. Phys. B 114 (2014)

k depends on: -mean fluence -size of the damage sites -pulse duration

Growth of damage site area versus shot number under laser irradiation at 351 nm— 3 ns.

An+1=Anexp(k)

R. Courchinoux et al., Proc. SPIE 5273 (2004)

Imp rovemen t : l ase r damage m i t i ga t i on Methods

Remove / Anneal / Transform…any potential initiating defect to recover initial material properties

Ideas:

CO2 CW10,6µmHF

CF4

fs

micropolishing Plasma torch Acid etching Laser thermal processing

Laser micromaching

Imp rovemen t : l ase r damage m i t i ga t i on Examples from l i t terature

S. Yang et al., Appl. Opt. 49 (2010)

J. Wolfe et al., Appl. Opt. 50 (2011)

CO2 Laser Galvo-scanner

AOM

fs LaserGalvo-

scanner

4.6µm CO2 Laser I. Bass et al., Proc. SPIE (2010)

Imp rovemen t : Lase r damage m i t i ga t i on Development of mit igat ion process for LMJ opt ics

Modeling surface defects for laser wave propagation

A. Bourgeade et al., JOSA B (2015)

Thermo-mechanics simulations

T. Doualle et al., submitted

Develop process to treat mm size damage Optimize LIDT of treated sites

P. Cormont et al., Opt. Express 18(2010)

Conc lus ions

Laser damage is a complex physical process wi th many potent ia l causes.

- improvement o f damage threshold requi res deta i led knowledge of these causes

-wi l l cont inue to be the subject o f extens ive research « Damage densi t ies / f luence » is more sui table than

« damage threshold » to def ine the damage resistance of an opt ical component

- improvement requi res reduct ion of damage dens i t ies , ie in i t ia t ing defect reduct ion

Damage growth is the main l imi tat ion for appl icat ion - can be mi t igated to recyle opt ics in some cases

Thank you f o r you r a t t en t i on !

laser damage resistance of optical components: limitations

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