Synthesis and estimation of third order non linear optical parameters of silver nano

colloids using Z- Scan technique.

Nonlinear Optics is the study of various phenomena related to the interaction of intense electromagnetic radiation with matter

Introduction

Telecommunications

Optical switching

Sensor protections

Optical information storage

Optical computing.

Applications of NLO

Materials which are chosen for these applications require excellent optical quality with large and stable optical nonlinearity in the solid state form. So the present need is to identify such materials

Requirements

Recently there has been a growing interest in the nonlinear optical properties of metal nanoparticles particularly of metal nanoparticles in colloidal solutions doped composite films.

Nonlinear optical properties of metal nanoparticles

Laser ablation.

Z- Scan Techniques.

Metal nanoparticles in colloidal solutions can be prepared by

Laser ablation is the process of removing material from a solid surface by irradiating it with a laser beam.

Laser ablation technique

Experimental set up

The Z-scan technique is to measure intensity dependent nonlinear susceptibilities of materials .

The technique is particularly useful when the nonlinear refraction is accompanied by nonlinear absorption and it allows the simultaneous measurement of nonlinear refractive index and nonlinear absorption coefficient.

The sample is translated in the Z-direction along the axis of a focused Gaussian beam and the far field intensity is measured as function of sample position.

The interaction of the medium with the laser light changes as the sample is moved. This is because the sample experiences different intensities, dependent on the sample position relative to the focus.

By measuring the transmittance through the sample as a function of the -position of the sample, information about the light-matter interaction can be extracted.

Z-Scan

Experimental set up

Preparation of Silver Metal nanocomposites

SEM Image of Ag.

UV-Visible spectra of Ag nanocolloid

In the present work, metal nanoparticles of silver prepared by laser ablation technique and nonlinear characterization were performed using Z-scan experiment using a pulsed laser.

RESULT

The nanoparticle formation through laser ablation techniques was confirmed with SEM and UV-Visible images .

The result suggests that silver nanocolloids are one of the suitable candidates for photonic applications.

Future directions are to executing the time-resolved studies of all these molecules to ascertain the response times.

model the nonlinear absorption behavior based on a five level model including all the possible absorption mechanisms such as excited state absorption, 2PA, 3PA etc.

fabricating the actual devices and testing their performance.

CONCLUSIONS AND FUTURE SCOPE