去氧核醣核酸 (deoxyribonucleic acid,DNA)為生命中傳遞遺傳資訊的重要分子。由於DNA分子如自組裝及分子辨識能力等數種特點,DNA在奈米科技領域的應用已日趨廣泛。近年來, DNA生物高分子聚合物已被研究出具有獨特的光學及電學性質,並運用在很多光電元件進而提升元件效率。 在本研究中我們利用光還原方式製備DNA-銀奈米粒子複合物並探究其非線性光學性質。我們使用波長532 nm 奈秒雷射脈衝為光源,利用Z scan技術獲得DNA奈米複合物之雙光子吸收係數(β)大於DNA生物高分子的β值。此結果顯示出由於銀奈米粒子的表面電漿共振效應,能增強其DNA奈米複合物非線性特性。而光學限制的應用也被研究及討論。
Deoxyribonucleic acid (DNA) is an important molecule carrying genetic information in organisms. Due to several features of DNA molecule, such as self-assembly and molecular recognition capabilities, DNA has found broad applications in nanotechnology. Recently, DNA biopolymer has also been reported to exhibit unique optical and electrical properties. Many optoelectronic devices have been implemented using DNA biopolymer with enhanced efficiency. In this study, we used a photochemical method to fabricate DNA-silver nanoparticles nanocomposite and investigated its nonlinear optical properties. A Z scan technique with nanosecond laser pulses at 532 nm was employed to obtain two-photon absorption coefficient. The value of DNA nanocomposite is larger than the value of DNA biomaterials.The results show that the nonlinear properties of DNA nanocomposite can be enhanced due to the surface plasmon resonance effect of silver nanoparticles. And the application in optical limiting was also studied and discussed