Instituto Nacional de Astrofísica, Óptica y

Electrónica

Ruben Ramos Garcia Julio Cesar Ramirez San Juan Enrique Aboytes Rodriguez Juan Pablo Padilla Martinez Nikolai Korneev Guillermo Aguilar (UCR)

Thermocavitation: A novel method of

cavitation produced by cw lasers

What is cavitation?

Francis turbine taken from

http://en.wikipedia.org/wiki/Cavitation

Formation of vapor bubbles

in liquids and their later

collapse.

Christopher E. Brennen “Cavitation and Bubble Dynamics” Oxford University Press, (1995).

Rayleigh Phil. Mag., 34, 94—98 (1917)

Formation of cavitation bubbles on an artificial stone in a shock

wave lithotripter. M.R. Bailey, Center for Industrial and Medical

Ultrasound, U. Washington)

Other applications: Homogenization of colloidal solutions Water purification & cleaning

Homeostasis Necrosis tumor cells

Immunotherapy Sonoporation

Phacoemulsificacion Lithotripsy

… much more!

Not all is bad news…

Hydraulic.

Acoustic

Particle

Optic

W. Lauterborn, ed., “Cavitation and inhomogeneities in underwater acoustics” Springer-Verlag (1980).

How cavitation is generated?

Cavitation in nature

Shock wave amplitude can be as large as 105 atm !!!

High velocity flow Bubble formation

Shock wave

BBC 'Weird Nature'

S. Ptterman, Phys. World May (1998)

Putterman Scientific American 1995

Laser-induced Cavitation

Vogel. et al Bubble Dynamics and Interface Phenomena

eds: J.R.Blake et al. Kluwer Acad. Publ., 105-117.

Low energy pulses produces very small

damage range and reduce undesirable

collateral damage.

Low absorption coefficient

30 ps

6 ns

50 mJ 1 mJ

1 mJ 10 mJ

30 ps & 50 mJ 30 ps & 1 mJ

6 ns & 1 mJ

6 ns & 10 mJ

vsw=2500 m/s

vb=390 m/s

Pmax=1.3GPa

vsw=2750 m/s

vb=780 m/s

Pmax=1.7GPa

vsw=3050 m/s

vb=1850 m/s

Pmax=2.4GPa

vsw=4450 m/s

vb=2450 m/s

Pmax=7.1GPa

Cavitation using CW lasers

PD

HP

Thermocavitation is attractive because it decrease costs and complexity in laser

systems.

Interesting but many questions remain to be answered

Experiment

50 100 150 200

20

30

40

50

60

70

Amplitude

Beam Power (mW)

Am

plit

ud

e (

a.u

.)

-1000

0

1000

2000

3000

4000

5000

Frequency

Fre

qu

en

cy (

Hz)

-1000 -500 0 500 1000

0

100

200

300

400

500

Frequency

Amplitude

Beam position (mm)

Am

pli

tud

e (

a.u

.)

0

1000

2000

3000

4000

Fre

qu

en

cy

(Hz)

Multibubble formation

More optical power but smaller bubbles?

Bubble’s temporal dynamics

0 20 40 60 80 100-80

-60

-40

-20

0

20

P= 69 mW

P=119 mW

velo

cit

y (

m/s

)

time (ms)

0 100 200

0

2

4

streak camera sweep

t i m e (ms )

(PD

sig

na

l)1

/2 a

.u.

collapse

0

50

100

150

200

250

Bu

bb

le ra

diu

s (m

m)

(a) (b)

JC Ramirez-San-Juan et al. "Time-resolved analysis of cavitation induced by CW lasers in absorbing liquids“ OPTICS EXPRESS 18, 8735-

8742 (2010)

[1] A. Vogel et al. , J. Fluid Mech., 206, 299-338 (1989).

Bubble is semi-spheric (g 1)

Tmax=328°C

@ tcav=2.8ms

,T

C k T Qt

Numerical Simulation

Tmax=263°C

@ tcav=40ms

120 mW Threshold power

70 mW

V.P. Skripov, P.A. Pavlov, High Temp. (USSR) 8, 782–787 (1970).

P. Kafalas, A.P. Ferdinand Jr., , Appl. Opt. 12, 29–33(1973).

T<Tsup (300 °C)

The ratio of energy deposition to heat

Diffusion determines the volume

available for vaporization

Larger volume Larger shock wave amplitude Larger bubbles

Applications: Micropatterning

Real time microhole fabrication in 60 nm Ti Optical Materials Express, Vol. 1 Issue 4, pp.598-604 (2011)

Opt. Mat Exp 2011

Applications: spatial filtering and point-

diffraction interferometers

Juan C. Aguilar et al 22nd ICO Puebla, Mexico

Jetting from cm sized drops Obreschkow et al. generated with an

electric discharge

S. T. Thoroddsen, et al. Spray and microjets produced by focusing a laser pulse into

a hemispherical drop. PHYSICS OF FLUIDS 21, 112101 2009

Laser disruption of the free surface of a hemispheric drop.

A Nd:YAG laser (532 nm) with 6 ns pulse

duration

Heijnen et al. Cavitation within a droplet. PHYSICS

OF FLUIDS 21, 091102 2009

15

THERMOCAVITATION WITHIN A DROPLET

50,000 fps

Period 20 ms

275 mW laser power

400 mm between the focal point and the

coverslip´s surface

23,000 fps

Period 43 ms

tcav ~ 82 ms

Submitted to Physics of Fluids

Liquid jet formed by thermocavitation on a thin film of solution (100 µm thickness). At different laser focus

position, a) 0, b) 100, c) 200, d) 300, e) 400 µm above the glass-liquid interface.

V= 4.8 m/s V=5.6 m/s V=32 m/s

V1=17 m/s

V2=23 m/s

Cavitation for transdermal drug delivery

Hua Tang, et al Pharmaceutical Research, Vol. 19, 1160-1169 (2002); Ahmet Tezel et al Biophysical Journal Vol 85 3502–3512 (2003)

Hideo Ueda et al Biol. Pharm. Bull. 32(5) 916-920 (2009)

Images of porcine skin sections where the FITC- Dextran FD4

solution was topically applied 2 ½ hrs. before the biopsy was

obtained.

J.P Padilla-Martínez et al, ILASS Americas, 23rd Annual Conference on Liquid Atomization and Spray Systems, Ventura, CA, May 2011

Holes (up) and depth (down) generated on agar gel (2%

concentration) by different laser powers: a) 153, b) 170, c) 180, d)

192 and e) 198 mW. The salution´s layer was ~300µm .

Percutaneous drug delivery (PDD)

is a promising alternative to

conventional routes of drug delivery,

However, the stratum corneum

(outermost layer of the skin) limits

drug delivery

Generation of ultrasound with cavitation

N Korneev et al “Ultrasound induced by CW laser cavitation bubbles” Journal of Physics: Conference Series 278 (2011) 012029

Pulsed Nd: YAG

Laser

Sample

CW laser

BS

M

M

Lens

GaAs Adaptive

photodetector

Amplifier

RF

U0

S. Stepanov, Photo-electromotive-force effect in

semiconductors, in Handbook of Advanced

Electronic and Photonic Materials and Devices,

vol. 2, ed. by H.S. Nalwa (Academic Press, New

York, 2001), pp. 205–272

Cavitation is an effective ultrasound source!!