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TWO-PHOTON IONIZATION OF SILVER CLUSTERS

V.Paployan, K.Madoyan, A.Melikyan,Russian-Armenian (Slavonic) State University, Yerevan,

Armenia

H.Minassian Yerevan Physics Institute, after A. Alikhanian,

Yerevan, Armenia

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Two-photon ionization (TPI) of metal clusters

Ultrahigh sensitivity of TPI can be used: • shape, rotational and vibrational temperatures

of the clusters with high accuracy• optical power limiting• nanolithography• biosensing

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,pump pr I I ionization potential

prhpumph

1. D. Bohm, D. Pines, Phys. Rev. 1953 2. I.E. Protsenko, A.V. Uskov, Physics-Uspekhi 2012

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Pump and Probe Electric FieldStrengths

int 03

2m

pump pumppump m

E E

03

2m

pr pr prpr m

E E

m dielectric functionof host medium

dielectric function

of metal

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Enhancement of Pump Wave

2pump i 0f E E

Ag m, 1

, 3Au Ag m Ag Auf f for the same because

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Approximations

301

30

Fermi

Drude

Drude

Drude

R nmvR

eER

for Ag fs

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TPI Probability

0,TPI pump probe TPIW g W

2 2

3 3,2 2

m mpump pr

pump m pr m

g

5 2prI eV eV

0TPI pump prW I I:

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Enhancement factors

,pump probe pump pump pr prg f f

2

32

mpr pr

pr m

f

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Internal field enhancement of the pump wave Ag m, 2.56

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Quality factor

, 3 , 0.04

75

SPSPQ eV eV

Q

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Conclusion

Surface plasmon assisted probability of TPI in SC is 400 times stronger as compared to the case when SP resonance is absent

High quality factor of TPI process Q ~ 75

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