We report that gallium nanoparticles, prepared by light-assisted self-assembly, show a nonlinear response to low-power optical excitation. Reversible reflectivity changes of several percent are induced as the result of light-induced structural transformations in the meta

Fedotov, V.A.

MacDonald, K.F.

Pochon, S.

Stevens, G.C.

Zheludev, N.I.

English

Southampton (e-Prints Soton)

 Fig. 2. Results of transient pump-probe experiments on the optical nonlinearity of gallium nanoparticles manufactured on the end of an optical fiber using the light-assisted self-assembly technique. Temperature dependencies of (a) reflectivity, (b)  induced  reflectivity  change,  (c)  relaxation  time.  Four  sets  of  experimental  data  are  shown:  ¾¨¾  increasing temperature for the first time after deposition; ¾▲¾ decreasing temperature; ---□--- increasing temperature again; ---○--- decreasing temperature again. The inset to (b) shows a typical reflectivity response curve from which the magnitude of the induced change (DR) and the relaxation time (Dt) are obtained. The inset to (c) illustrates how the metallization of a particle may occur by formation of: (i) a metallic shell; (ii) metallic inclusions; or (iii) both. 01234595 140 185 230 275 320Temperature, KRelaxation time, s(d)16 msat 171K-0.500.511.522.533.5Induced reflectivity change, % (b)0.940.9711.031.061.091.12Reflectivity, arb. units(a)(c) (i) (ii) (iii)Ground-stateMetallicExcitation5 msDtDR

Optical nonlinearity and light-induced structural transformations in gallium nanoparticles

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