Amplified Spontaneous Emission Of Fluorescent Dye-doped DNA-CTMA Thin Films

As the application of DNA biological materials in photonics and optical electronics,and DNA has an unique structure with double helix,makes it attract scientists'attentions.An ordinary polymer has some advantages,such as the various structures,inexpensive,obtaining easily and big crossing sectional areas.But DNA having unique optical properties,is an excellent photoelectron materials.high optical transmission,high thermal stability and low optical loss are all the advatages of DNA.The preparation of the fluorescent dye(rhodamine-6G and rhodamine-B)doped DNA-CTMA copmplex thin films and research the phoenomenon of amplified spontaneous emission(ASE) in the thin films are mainly studied in this thesis.The Rh6G/RhB/DNA-CTMA thin films was fabricated by spin-coating method.The optical propertiesof the thin film,such AFM photo and spectrum,were taken. the phoenomenon of amplified spontaneous emission was observed and discussed using experimental device.The optical properties and component application of DNA-lipid compound thin films are described in the first part of the thesis.The spectral properties of dye doped compound thin films are reviewed.Because of the double helix structure in DNA,it can make many functional dyes insert in it,resulting in the enhanced fluorescence intensity.The basic principle of laser,the structure of dye laser,and some parameters comparison of the common dye laser are taken in the second part. Amplified spontaneous emission is a transition state between laser and fluorescence . The population of laser material has not reached the reversal degree of laser oscillation threshold,and laser oscillations has not been formed.The difference of amplified spontaneous emission and fluorescence is the distribution.The former is no longer uniform. The amplified spontaneous emission laser with no cavity and tenuous has better spatial coherence.The third part and the forth part are the experiment. The fluorescent dye rhodamine-6G and rhodamine-B doped DNA-CTMA thin films were prepared by spin-coating technology. The quality and optical spectra properties of Rh6G/RhB/DNA-CTMA thin films were characterized by the measurements of surface morphology, UV/Vis/Infrared absorption spectra and fluorescence spectra. The amplified spontaneous emission of dye-doped DNA-CTMA thin films with different dye ratios was researched experimentally by pumping of Nd:YAG pulse laser at wavelength 532nm, and was explained theoretically. The experiment results show that the narrowing phenomenon of emission spectra of Rh6G/RhB/DNA-CTMA thin films is very clear and strong when increasing the laser energy density. Comparing to single dye doped DNA-CTMA thin films, the hybrid Rh6G/RhB/DNA-CTMA thin films is a potential candidate as an organic polymer laser material because it exhibits more wider tuning range of the ASE spectrum..