Thermo-optic nonlinear response of silver nanoparticle colloids under a low power laser irradiation at 532 nm

Abstract

The thermo-optical properties of silver nanoparticles (AgNPs) in the water are investigated under irradiation of a continuous wave (CW) laser at 532 nm. Thermal conductivity of the AgNP colloids is estimated using the Maxwell model. The closed Zscan measurements reveal thermal contribution for the nonlinear refractive index of the AgNPs. The Z-scan behavior is investigated based on nonlocal thermo-optic process. It is shown that the aberrant thermal lens model is in excellent agreement with the Z-scan experimental results of the sample. A fit allows extracting the values of nonlinear refractive index and thermo-optic coefficient to be À1.0 Â 10 À8 cm 2 /W and À0.99 Â 10 À4 W/mK, respectively. Our results suggest that thermal nonlinear effects play an important role in the development of photonic application involving metal nanoparticle colloids and in the investigation of nonlocal nonlinear processes. , and cooling systems [10], where a temperature change within and around metal nanoparticles may alter the characteristics of their functionality. This may lead to a large spatial nonlocality on the refractive index changes of the medium. The thermal lens phenomenon has been shown to contribute to significant extent to the nonlinear optical response of composite media containing metal nanoparticles [11][12][13]. Large enhancement factors were observed for thermal nonlinear refractive index and thermo-optic coefficients of the colloid due to the presence of gold nanoparticles [11,12]. Recent works predicted and observed optical nonlocal effects exploiting the thermal nonlinearity in dye materials [14,15], polymers [16][17][18], phthalocyanines [19,20] Thermal lensing occurs as energy absorbed from a Gaussian laser beam produces heating of an absorbing medium about the beam axis. A radially dependent

Large thermally induced nonlinear refraction of gold nanoparticles stabilized by cyclohexanone

“…Our results show that the presence of the AuNPs enhances optical properties of the colloids as summarized in Table 1. The measured values of nonlinear refraction coefficients of the AuNPs are compared with the recently reported values of nonlinear refraction coefficient of different materials 30, 33, 36, 52–57 and listed in Table 2. In Ref.…”

Optical limiting response of Ag2S nanoparticles synthesized by laser ablation of silver target in DMSO

“…A similar optical geometry to that given in Ref. [28] was used for nonlinear transmittance measurement. An attenuator and a beam splitter were used to control the single-pulse energy of the laser beam.…”

“…The details of the experimental procedure have been given in Ref. [28]. The crystal structure of the Ag 2 S NPs was investigated by a Bruker D8 ADVANCE X-ray diffractometer with high-intensity Cu Ka radiation (l ¼ 1.5406 Å ).…”

Optical and Structural Properties of Silver Nanoparticles Embedded in Indium Oxide Films

“…The values reported here are higher by two orders than the reported value for Au and Ag colloids. 44,45 The di®erences may rise to larger thermal contribution in the case of the colloidal solutions.…”