Nano Archive

Near-Field CARS with Micro- and Nano-Particle

Ooi, CHR (2010) Near-Field CARS with Micro- and Nano-Particle. XXII INTERNATIONAL CONFERENCE ON RAMAN SPECTROSCOPY . ISSN 0094-243X

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Spatial dependence of coherent anti-Stokes Raman scattering (CARS) intensity and spectra for a spherical particle are studied for different sizes, ranging from micrometers to nanometers. Effects of near field on the spectra are analyzed, showing potential application as nano-sensor in microscopy and imaging. The results can be extended to an array of nanospheres. The CARS process has been developed into a versatile real-time detection technique in spectroscopy and microscopy [1]. In particularly, backscattered ultra-violet CARS implemented on LIDAR system [2] is promising for remote detection of molecular species present in hazardous biological aerosols with microscale dimension. In practice, the aerosols could be in any dimension. Thus, we need to know study a modified the setup of the CARS technique for reliable detection of chemicals in micro- and nano-particles using near-field effects. We have developed a nonlinear semiclassical microscopic theory to describe the CARS spectra for a particle composed of a collection of arbitrarily complex molecules [3] as well as simple few levels quantum systems [2]. The theory provides useful results on the CARS spectra for any observation angle and for any form of laser pulses [3]. Here, we focus on the spectra in the near field. We wish to study how the spectra vary with the near field distance with focused laser pulses. We also analyze to what extend the dimension of the particle and the focusing laser affect the lensing effect which could enhance the backscattered light.

Item Type:Article
Subjects:Analytical Science > Nanotechnology for sensing and actuating
Physical Science > Nano objects
ID Code:9660
Deposited By:CSMNT
Deposited On:25 Sep 2010 11:11
Last Modified:25 Sep 2010 11:11

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