OSA's Digital Library

Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 20, Iss. 4 — Feb. 13, 2012
  • pp: 3990–3996
« Show journal navigation

Nonlinear microscopy techniques for assessing the UV laser polymer interactions

Alexandros Selimis, George J. Tserevelakis, Sotiria Kogou, Paraskevi Pouli, George Filippidis, Natalia Sapogova, Nikita Bityurin, and Costas Fotakis  »View Author Affiliations


Optics Express, Vol. 20, Issue 4, pp. 3990-3996 (2012)
http://dx.doi.org/10.1364/OE.20.003990


View Full Text Article

Acrobat PDF (707 KB)





Browse Journals / Lookup Meetings

Browse by Journal and Year


   


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

Share
Citations

Abstract

A new diagnostic approach for assessing the in-depth laser induced modifications upon ultraviolet polymer irradiation is presented. The methodology relies on the observation of morphological alterations in the bulk material (Paraloid B72) by using third harmonic generation. This non destructive methodology allows the detailed and accurate imaging of the structurally laser modified zone extent in the vicinity of the irradiated area. Additionally, for the first time, the visualization and quantitative determination of the contour of the laser-induced swelling/bulk material interface is reported. The observed polymer surface swelling following single-pulse KrF laser irradiation at sub-ablation fluences is interpreted in the context of a model for laser-induced bubble formation due to droplet explosion mechanism.

© 2012 OSA

1. Introduction

Laser ablation of polymers has proven to be important for a great variety of applications, while at the same time has been the subject of extensive scientific research. In fact, many applications have been put on the map due to the characteristic features of UV laser processing, even if the mechanistic aspects underlying polymer ablation are still under investigation. To illuminate the processes taking place upon UV laser irradiation of polymers (mainly with nanosecond laser pulses), a range of studies [1

1. D. Bäuerle, Laser Processing and Chemistry (Springer-Verlag, 2000).

3

3. G. Bounos, A. Selimis, S. Georgiou, E. Rebollar, M. Castillejo, and N. Bityurin, “Dependence of ultraviolet nanosecond laser polymer ablation on polymer molecular weight: Poly(methyl methacrylate) at 248 nm,” J. Appl. Phys. 100(11), 114323 (2006). [CrossRef]

] have examined the dependence of ablation characteristics (threshold, etching efficiency, nature and range of products) on laser irradiation (laser wavelength, fluence and pulse width) and material parameters (absorptivity, molecular weight, chemical structure, etc). The laser-polymer interactions occurring below the ablation threshold regime, as well as the in-depth laser induced changes upon UV polymer irradiation have also been examined [4

4. N. Bityurin, “Model for laser swelling of a polymer film,” Appl. Surf. Sci. 255(24), 9851–9855 (2009). [CrossRef]

6

6. S. Georgiou, “Laser cleaning methodologies of polymer substrates,” Adv. Polym. Sci. 168, 1–49 (2004).

]. For achieving the optimum result, it is crucial that the initial steps of materials processing by the UV laser beam are monitored and understood. Towards this end, the study of the sub-ablation processes can reveal the dynamics of the laser interactions with polymers that lead to the onset of ablation. Furthermore, the determination of the laser affected zone extent is of great importance since it crucially determines the successful implication of laser ablation in diverse applications. This is precisely the problem that the present work tries to answer; the explicit determination of the laser induced swelling/ bulk material interface.

It is herein demonstrated that nonlinear imaging (THG) can be successfully applied for the clarification of intense bubble-formation phenomena effected upon KrF laser irradiation of Paraloid B72 (PB72) [7

7. P. Pouli, A. Nevin, A. Andreotti, P. Colombini, S. Georgiou, and C. Fotakis, “Laser assisted removal of synthetic conservation materials from paintings using UV radiation of ns and fs pulse duration: morphological studies on model samples,” Appl. Surf. Sci. 255(9), 4955–4960 (2009). [CrossRef]

]. This technique, being a single beam one and allowing rapid measurements (~1 min) of high resolution (~1 μm), is competitive to the till now employed techniques [8

8. N. Hutchings, T. L. Simpson, C. Hyun, A. A. Moayed, S. Hariri, L. Sorbara, and K. Bizheva, “Swelling of the human cornea revealed by high-speed, ultrahigh-resolution optical coherence tomography,” Invest. Ophthalmol. Vis. Sci. 51(9), 4579–4584 (2010). [CrossRef] [PubMed]

]. Most importantly, the significance of this technique lays on the fact that, for the first time, the contours of the laser induced swelling/bulk material interface are accurately outlined and quantified. The enlightenment of the dependence of the turbid foamed domain localization (swelling) within the polymeric materials on the laser irradiation parameters provides the differentiation between the mechanisms of bubble creation and growth.

2. Experimental

80 μm films of Paraloid B72 (a 70:30 co-polymer of ethyl methacrylate and methyl acrylate with molecular weight ~105 kDa) were investigated. Solutions of the co-polymer (in acetone) were casted on a round glass slide of 35 mm diameter and ~70 μm thickness and dried in air. The polymer films were irradiated with a 30 ns KrF laser (Lambda Physik-LPX 210) emitting at 248 nm with single pulses at sub-ablation fluences. It should be also mentioned that PB72 is transparent in the near UV (340 nm), visible and infrared spectral regions [7

7. P. Pouli, A. Nevin, A. Andreotti, P. Colombini, S. Georgiou, and C. Fotakis, “Laser assisted removal of synthetic conservation materials from paintings using UV radiation of ns and fs pulse duration: morphological studies on model samples,” Appl. Surf. Sci. 255(9), 4955–4960 (2009). [CrossRef]

].

3. Results

The collected THG signals are generated not only from the air/polymer, polymer/glass and glass/air interfaces but also from the air/laser-induced swelling and laser-induced swelling/ bulk material interfaces. In fact, the latter signals are those that define the extent of polymer swelling following irradiation. However, the light scattering from the air/laser-induced swelling interface hinders the beam propagation to the underlying layers obstructing thus the THG signal generation and the definition of the polymer swelling extent. To overcome this problem the sample was reversed and THG signals were collected from each side of the sample. By this configuration, we illustrated both the front (towards the air) and the back (towards the bulk material) border of the polymer swelling. The superimposed images from these measurements for two indicative laser fluences are shown in Fig. 1
Fig. 1 THG images from a Paraloid B72 film following single pulse irradiation at 248 nm (illustrating a cross section of the irradiated area). The THG signal from the front and the back border of the polymer swelling are illustrated with green and red color respectively indicating its extent following irradiation at φLASER = 400 (a) and 1550 (b) mJ/cm2. The insets present the corresponding unprocessed (raw) THG images prior to the apparent depth correction. The relative percent difference of THG signal across a single column is in the order of 10 – 25% if we compare the maximum column value with the two adjacent THG values.
. The importance of our results lays on the illustration of the polymer swelling towards the bulk material. By this technique the whole laser affected region in the neighborhood of the irradiated area can be visualized.

From these images, we measured the distance values of both the front and the back border of the swelling from the polymer surface for a series of laser fluences. The former are in accordance with those measured by conventional profilometry confirming, thus, the accuracy of our technique, while the latter are presented in Fig. 2
Fig. 2 Experimental results of the distance values from the back border of the Paraloid B72 swelling (towards the bulk material) to the polymer surface vs. the incident fluence following single pulse irradiation at 248 nm together with the theoretical curve. Droplet explosion model, initial droplet radius 65 nm, αeff = 1000 cm−1.
as a function of the incident laser fluence following single pulse irradiation at 248 nm. The thermally affected swelled zone measured herein is attributed to cavity formation, on which our discussion relies.

4. Discussion

The cavity formed within the laser irradiated materials can be due to cavitation bubbles [15

15. G. Paltauf and P. E. Dyer, “Photomechanical processes and effects in ablation,” Chem. Rev. 103(2), 487–518 (2003). [CrossRef] [PubMed]

] created and grown during the rarefaction wave (originated from the reflection of the pressure wave from the free surface of the sample). A detailed approach on KrF excimer laser polymer bubbling is published in [16

16. S. Lazare, I. Elaboudi, M. Castillejo, and A. Sionkowska, “Model properties relevant to laser ablation of moderately absorbing polymers,” Appl. Phys., A Mater. Sci. Process. 101(1), 215–224 (2010). [CrossRef]

]. The creation of cavitation bubbles relies on the glass transition temperature (Tg) of the polymer, the excess of the laser heated material temperature over Tg, as well as on the value of the maximal tensile stress generated by the laser pulse. Comparison with the bubbling conditions for other polymers reviewed in [16

16. S. Lazare, I. Elaboudi, M. Castillejo, and A. Sionkowska, “Model properties relevant to laser ablation of moderately absorbing polymers,” Appl. Phys., A Mater. Sci. Process. 101(1), 215–224 (2010). [CrossRef]

], and simple estimations show that cavitation bubbles cannot be created by such a mechanism at the experimental threshold fluences taking into account the spectroscopic measured absorption coefficient of PB72, α = 150 cm−1, at 248 nm.

The situation significantly changes if we suggest that the effective absorption coefficient at the irradiation conditions can differ from the above linear value. The concept of an effective absorption coefficient is commonly used in polymer ablation studies [2

2. T. Lippert and J. T. Dickinson, “Chemical and spectroscopic aspects of polymer ablation: special features and novel directions,” Chem. Rev. 103(2), 453–486 (2003). [CrossRef] [PubMed]

]. In fact, the nonlinear absorption with almost fixed value at a wide range of laser intensities is observed in doped PMMA irradiated by a KrF excimer laser [3

3. G. Bounos, A. Selimis, S. Georgiou, E. Rebollar, M. Castillejo, and N. Bityurin, “Dependence of ultraviolet nanosecond laser polymer ablation on polymer molecular weight: Poly(methyl methacrylate) at 248 nm,” J. Appl. Phys. 100(11), 114323 (2006). [CrossRef]

]. As far as it concerns the herein studied polymer, following measurements performed upon KrF irradiation at the studied fluences indicated the effective absorption coefficient for PB72 to be in the range of 1000 cm−1.

The experimental curve of the rare border position vs. φLASER consists of two parts (Fig. 2). At high laser fluences zrear levels off due to significant mass and energy loss (owing to either the volatile elimination and ablation onset [16

16. S. Lazare, I. Elaboudi, M. Castillejo, and A. Sionkowska, “Model properties relevant to laser ablation of moderately absorbing polymers,” Appl. Phys., A Mater. Sci. Process. 101(1), 215–224 (2010). [CrossRef]

], or to the self-influence of bubbling on bubbling kinetics [17

17. M. Strauss, Y. Kaufman, M. Sapir, P. A. Amendt, R. A. London, and M. E. Glinsky, “Self-consistent coupling of cavitation bubbles in aqueous systems,” J. Appl. Phys. 91(7), 4720–4725 (2002). [CrossRef]

]). In the following we discuss the first part of the experimental curve suggesting that the growth of the each bubble occurs independently.

Let us consider a liquid droplet of radius r within the polymer matrix. This droplet can be originated from solvent residuals from casting. Upon laser irradiation both the matrix and the droplet are heated; the droplet reaching its boiling temperature. If the pressure of the (liquid) droplet saturated vapour is equal to the surface tension pressure, then the cavity will expand. The evaporating droplet will provide enough gaseous molecules to support the bubble growth. If the growth would proceed up to the complete evaporation of the liquids, then the pressure will change from the saturated pressure to the pressure of the ideal gas with the fixed number of gas molecules within the bubble.

We consider the bubble growth dynamic within the frame of the equation:
drdt=ptrη2ση
(2)
which can be obtained from Rayleigh-Plesset equation [18

18. J. P. Frank and J.-M. Mishel, Fundamentals of Cavitation (Kluwer Ac. Publ., 2004).

] for the case of small bubbles in high-viscous liquid (in which the inertial terms are neglected). Here pt is the tensile stress, η and σ are the viscosity and the surface tension correspondingly.

The temperature dependence of the surface tension coefficient can be addressed by the Guggenheim expression with critical temperature, σ = σ0(1-T/Tc)11/9, Tc ≈700-1000 K. For polymer melts above Tg, η strongly depends on temperature and the Williams-Landel-Flerry formula η = η0exp(T*/(T-T2)) can be used for this dependence, with T* ≈2069 K, T2 = Tg–ΔT2, ΔT2 ≈51.6 K and according to Avramov’s consideration [19

19. I. Avramov, “Viscosity in disordered media,” J. Non-Cryst. Solids 351(40-42), 3163–3173 (2005). [CrossRef]

], η0 ≈10−4 erg s/cm3.

Equation (2) was employed by Zeldovich [20

20. Ya. B. Zeldovich, “Theory of new phase formation. Cavitation,” J. Exp. Theor. Phys. 12, 525–538 (1942).

] when considering the cavitation nucleation phenomenon. This equation describes the ‘classical trajectory’ neglecting the fluctuations. In Eq. (2) pt = pvpA, where vapour pressure pv is

pv(r,T)=psat(T)pAexp(ΛkBTboilingΛkBT)ifr<rsandpv(r,T)=ρlμlRgT(r0r)1/3ifr>rs
(3)

Here r0 is the initial radius of the droplet and rs = r0l Rg T/μl psat(T))1/3 corresponds to its full evaporation. Tboiling is the boiling temperature of the liquid at atmospheric pressure pA, Λ is the latent heat of the liquid evaporation, ρl and μl are the density and molar mass of the liquid, kB is Boltzmann constant and Rg is the universal gas constant. In the case of PB72 the liquid is the solvent acetone with μl = 58.08 g/mol, ρl = 0.79 g/cm3, Tboiling = 329.1 K, Λl = 29.1 kJ/mol.

In our model, we solve Eq. (2) assuming that the gas temperature inside the bubble is equal to the temperature of the surrounding material. That is, in Eq. (3), T = T(z, t) is the solution of Eq. (4)
Tt=DT2Tz2
(4)
with initial conditions T(z,0) = Troom + (αφ/cPρ)e-αz and boundary condition ∂T/∂z|z = 0 = 0. The droplet explosion starts when psat(T) = 2σ(T)/r0 + pA. The growing continues until pv(r,T) = 2σ(T)/r + pA and then the radius relaxes. It follows from Eq. (4) with the above initial and boundary conditions, that for each point z>0 the temperature initially increases, then approaches the maximum value Tmax(z) and finally decreases. Calculations show that for different fluences at the rear border of the modified layer, zrear (measured in the experiment and shown in Fig. 2) the following approximate relation holds:

psat(Tmax(zrear))2σ(Tmax(zrear))r0+pA
(5)

This means that for different fluences, above the threshold, the position of the rear border of bubbling zone corresponds to the fixed value of maximal temperature Tmax(zrear,φ) ≈const. Experimentally, at ϕ = 0.4 J/cm2, the rear border occurs at distance zrear ≈10µm from the initial surface. For αeff = 1000 cm−1, the corresponding value of Tmax (zrear = 10μm, ϕ = 0.4 J/cm2) is calculated to be 394 K. We designate it as T*. Thus, the equation from which the dependence zrear(φ)can be obtained, reads:

Tmax(zrear,ϕ)T*
(6)

Figure 2 shows the corresponding curve together with the experimental data. From (5) the value of the initial droplet radius can be found, which in our case is r0 ≈2σ(T*)/(psat(T*)- pA) ≈ 65 nm.

5. Conclusions

The potential of THG imaging technique for reliably monitoring the presence and extent of the laser induced structural modifications in the bulk polymer following UV laser irradiation is herein demonstrated. The advantage of using nonlinear microscopy over conventional techniques for the determination of the laser induced swelling/bulk material interface contour is also shown. The experimental data can be explained on the assumption that the laser light absorption is addressed by the effective absorption coefficient which significantly differs from the value measured at small intensities. The position of the rear border of the foamed layer, measured by the THG technique, as a function of the laser fluence, corresponds approximately to the fixed value of the maximal temperature. The proposed droplet explosion model of bubble creation satisfactorily fits the experimental data if αeff = 1000 cm−1 and the initial radius of the droplet is about r0 65 nm.

Acknowledgments

Research at IESL-FORTH was supported in part by the EC FP7 projects “LASERLABEUROPE” (No 228334), “CHARISMA” (No 228330) and “FAST-DOT” (No 224338). G. J. T. acknowledges the “HERACLITUS II-University of Crete” funded by the European Social Fund and national resources. N. S. and N. B. thank RFBR (grant 11-02-97053-а) for partial financial support.

References and links

1.

D. Bäuerle, Laser Processing and Chemistry (Springer-Verlag, 2000).

2.

T. Lippert and J. T. Dickinson, “Chemical and spectroscopic aspects of polymer ablation: special features and novel directions,” Chem. Rev. 103(2), 453–486 (2003). [CrossRef] [PubMed]

3.

G. Bounos, A. Selimis, S. Georgiou, E. Rebollar, M. Castillejo, and N. Bityurin, “Dependence of ultraviolet nanosecond laser polymer ablation on polymer molecular weight: Poly(methyl methacrylate) at 248 nm,” J. Appl. Phys. 100(11), 114323 (2006). [CrossRef]

4.

N. Bityurin, “Model for laser swelling of a polymer film,” Appl. Surf. Sci. 255(24), 9851–9855 (2009). [CrossRef]

5.

A. Vogel and V. Venugopalan, “Mechanisms of pulsed laser ablation of biological tissues,” Chem. Rev. 103(2), 577–644 (2003). [CrossRef] [PubMed]

6.

S. Georgiou, “Laser cleaning methodologies of polymer substrates,” Adv. Polym. Sci. 168, 1–49 (2004).

7.

P. Pouli, A. Nevin, A. Andreotti, P. Colombini, S. Georgiou, and C. Fotakis, “Laser assisted removal of synthetic conservation materials from paintings using UV radiation of ns and fs pulse duration: morphological studies on model samples,” Appl. Surf. Sci. 255(9), 4955–4960 (2009). [CrossRef]

8.

N. Hutchings, T. L. Simpson, C. Hyun, A. A. Moayed, S. Hariri, L. Sorbara, and K. Bizheva, “Swelling of the human cornea revealed by high-speed, ultrahigh-resolution optical coherence tomography,” Invest. Ophthalmol. Vis. Sci. 51(9), 4579–4584 (2010). [CrossRef] [PubMed]

9.

Y. Barad, H. Eisenberg, M. Horowitz, and Y. Silberberg, “Nonlinear scanning laser microscopy by third harmonic generation,” Appl. Phys. Lett. 70(8), 922–924 (1997). [CrossRef]

10.

M. Müller, J. Squier, K. R. Wilson, and G. J. Brakenhoff, “3D microscopy of transparent objects using third-harmonic generation,” J. Microsc. 191(3), 266–274 (1998). [CrossRef] [PubMed]

11.

D. Débarre and E. Beaurepaire, “Quantitative characterization of biological liquids for third-harmonic generation microscopy,” Biophys. J. 92(2), 603–612 (2007). [CrossRef] [PubMed]

12.

N. Olivier, F. Aptel, K. Plamann, M. C. Schanne-Klein, and E. Beaurepaire, “Harmonic microscopy of isotropic and anisotropic microstructure of the human cornea,” Opt. Express 18(5), 5028–5040 (2010). [CrossRef] [PubMed]

13.

G. J. Tserevelakis, G. Filippidis, A. J. Krmpot, M. Vlachos, C. Fotakis, and N. Tavernarakis, “Imaging Caenorhabditis elegans embryogenesis by third-harmonic generation microscopy,” Micron 41(5), 444–447 (2010). [CrossRef] [PubMed]

14.

G. W. White, “Improving the accuracy of vertical measurements under the microscope,” Microscope 18, 51–59 (1970).

15.

G. Paltauf and P. E. Dyer, “Photomechanical processes and effects in ablation,” Chem. Rev. 103(2), 487–518 (2003). [CrossRef] [PubMed]

16.

S. Lazare, I. Elaboudi, M. Castillejo, and A. Sionkowska, “Model properties relevant to laser ablation of moderately absorbing polymers,” Appl. Phys., A Mater. Sci. Process. 101(1), 215–224 (2010). [CrossRef]

17.

M. Strauss, Y. Kaufman, M. Sapir, P. A. Amendt, R. A. London, and M. E. Glinsky, “Self-consistent coupling of cavitation bubbles in aqueous systems,” J. Appl. Phys. 91(7), 4720–4725 (2002). [CrossRef]

18.

J. P. Frank and J.-M. Mishel, Fundamentals of Cavitation (Kluwer Ac. Publ., 2004).

19.

I. Avramov, “Viscosity in disordered media,” J. Non-Cryst. Solids 351(40-42), 3163–3173 (2005). [CrossRef]

20.

Ya. B. Zeldovich, “Theory of new phase formation. Cavitation,” J. Exp. Theor. Phys. 12, 525–538 (1942).

OCIS Codes
(140.3390) Lasers and laser optics : Laser materials processing
(140.6810) Lasers and laser optics : Thermal effects
(160.5470) Materials : Polymers
(190.1900) Nonlinear optics : Diagnostic applications of nonlinear optics
(180.4315) Microscopy : Nonlinear microscopy

ToC Category:
Microscopy

History
Original Manuscript: November 23, 2011
Revised Manuscript: January 12, 2012
Manuscript Accepted: January 12, 2012
Published: February 2, 2012

Citation
Alexandros Selimis, George J. Tserevelakis, Sotiria Kogou, Paraskevi Pouli, George Filippidis, Natalia Sapogova, Nikita Bityurin, and Costas Fotakis, "Nonlinear microscopy techniques for assessing the UV laser polymer interactions," Opt. Express 20, 3990-3996 (2012)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-20-4-3990


Sort:  Author  |  Year  |  Journal  |  Reset  

References

  1. D. Bäuerle, Laser Processing and Chemistry (Springer-Verlag, 2000).
  2. T. Lippert and J. T. Dickinson, “Chemical and spectroscopic aspects of polymer ablation: special features and novel directions,” Chem. Rev.103(2), 453–486 (2003). [CrossRef] [PubMed]
  3. G. Bounos, A. Selimis, S. Georgiou, E. Rebollar, M. Castillejo, and N. Bityurin, “Dependence of ultraviolet nanosecond laser polymer ablation on polymer molecular weight: Poly(methyl methacrylate) at 248 nm,” J. Appl. Phys.100(11), 114323 (2006). [CrossRef]
  4. N. Bityurin, “Model for laser swelling of a polymer film,” Appl. Surf. Sci.255(24), 9851–9855 (2009). [CrossRef]
  5. A. Vogel and V. Venugopalan, “Mechanisms of pulsed laser ablation of biological tissues,” Chem. Rev.103(2), 577–644 (2003). [CrossRef] [PubMed]
  6. S. Georgiou, “Laser cleaning methodologies of polymer substrates,” Adv. Polym. Sci.168, 1–49 (2004).
  7. P. Pouli, A. Nevin, A. Andreotti, P. Colombini, S. Georgiou, and C. Fotakis, “Laser assisted removal of synthetic conservation materials from paintings using UV radiation of ns and fs pulse duration: morphological studies on model samples,” Appl. Surf. Sci.255(9), 4955–4960 (2009). [CrossRef]
  8. N. Hutchings, T. L. Simpson, C. Hyun, A. A. Moayed, S. Hariri, L. Sorbara, and K. Bizheva, “Swelling of the human cornea revealed by high-speed, ultrahigh-resolution optical coherence tomography,” Invest. Ophthalmol. Vis. Sci.51(9), 4579–4584 (2010). [CrossRef] [PubMed]
  9. Y. Barad, H. Eisenberg, M. Horowitz, and Y. Silberberg, “Nonlinear scanning laser microscopy by third harmonic generation,” Appl. Phys. Lett.70(8), 922–924 (1997). [CrossRef]
  10. M. Müller, J. Squier, K. R. Wilson, and G. J. Brakenhoff, “3D microscopy of transparent objects using third-harmonic generation,” J. Microsc.191(3), 266–274 (1998). [CrossRef] [PubMed]
  11. D. Débarre and E. Beaurepaire, “Quantitative characterization of biological liquids for third-harmonic generation microscopy,” Biophys. J.92(2), 603–612 (2007). [CrossRef] [PubMed]
  12. N. Olivier, F. Aptel, K. Plamann, M. C. Schanne-Klein, and E. Beaurepaire, “Harmonic microscopy of isotropic and anisotropic microstructure of the human cornea,” Opt. Express18(5), 5028–5040 (2010). [CrossRef] [PubMed]
  13. G. J. Tserevelakis, G. Filippidis, A. J. Krmpot, M. Vlachos, C. Fotakis, and N. Tavernarakis, “Imaging Caenorhabditis elegans embryogenesis by third-harmonic generation microscopy,” Micron41(5), 444–447 (2010). [CrossRef] [PubMed]
  14. G. W. White, “Improving the accuracy of vertical measurements under the microscope,” Microscope18, 51–59 (1970).
  15. G. Paltauf and P. E. Dyer, “Photomechanical processes and effects in ablation,” Chem. Rev.103(2), 487–518 (2003). [CrossRef] [PubMed]
  16. S. Lazare, I. Elaboudi, M. Castillejo, and A. Sionkowska, “Model properties relevant to laser ablation of moderately absorbing polymers,” Appl. Phys., A Mater. Sci. Process.101(1), 215–224 (2010). [CrossRef]
  17. M. Strauss, Y. Kaufman, M. Sapir, P. A. Amendt, R. A. London, and M. E. Glinsky, “Self-consistent coupling of cavitation bubbles in aqueous systems,” J. Appl. Phys.91(7), 4720–4725 (2002). [CrossRef]
  18. J. P. Frank and J.-M. Mishel, Fundamentals of Cavitation (Kluwer Ac. Publ., 2004).
  19. I. Avramov, “Viscosity in disordered media,” J. Non-Cryst. Solids351(40-42), 3163–3173 (2005). [CrossRef]
  20. Ya. B. Zeldovich, “Theory of new phase formation. Cavitation,” J. Exp. Theor. Phys.12, 525–538 (1942).

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.

Figures

Fig. 1 Fig. 2
 

« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited