Tunable optical Kerr effects of DNAs coupled to quantum dots

Yang Li,Ka-Di Zhu

doi:10.1186/1556-276x-7-660

Abstract

The coupling between DNA molecules and quantum dots can result in impressive nonlinear optical properties. In this paper, we theoretically demonstrate the significant enhancement of Kerr coefficient of signal light using optical pump-probe technique when the pump-exciton detuning is zero, and the probe-exciton detuning is adjusted properly to the frequency of DNA vibration mode. The magnitude of optical Kerr coefficient can be tuned by modifying the intensity of the pump beam. It is shown clearly that this phenomenon cannot occur without the DNA-quantum dot coupling. The present research will lead us to know more about the anomalous nonlinear optical behaviors in the hybrid DNA-quantum dot systems, which may have potential applications in the fields such as DNA detection.

Highlights

Biomaterials are drawing more and more attention since they often present special properties which are not obtained from traditional inorganic or organic materials
The DNA molecules in solution form can be distorted in mess, one can extend these molecules into linear form with electromagnetic field or fluid force [28]
The importance of the coupling between quantum dot and DNA molecules is obvious since the enhancement of optical Kerr effect could not occur in such a system when λ = 0

Summary

Introduction

Biomaterials are drawing more and more attention since they often present special properties which are not obtained from traditional inorganic or organic materials. Researches have been interested in DNA for various reasons, such as potential applications of DNA assembly in molecular electronic devices [1], nanoscale robotics [2], and DNA-based computation [3]. Thin film of DNA-CTMA has been used successfully in various applications such as organic light emitting diodes, a cladding and host material in nonlinear optical devices, and organic field-effect transistors because of its nature of large dielectric constant and large band gap [4]. A better understanding of the nonlinear optical properties of DNA materials will undoubtedly lead us to more exciting applications. Many researches on nonlinear optical properties of DNA materials have been undertaken. Samoc et al have studied the nonlinear refractive index and the two-photon absorption coefficient of native (sodium salt)

Methods

Results

Conclusion