Preparation And Spectrum Measurement Of PbSe Quantum-dot Doped Fibers

Studies on semiconductor nanocrystal quantum dots(QDs) develop rapidly in recent years. We can obtain variations of emission wavelengths and bandwidths of QDs by controlling the size and type of doped QDs. For IV-VI PbSe QD, the absorption-emission spectra covers a broad wideband, including the near infrared communication band(around 1550 nm). Because of the characteristics of the wavelength can be adjusted, PbSe QD has become a new researching hotspot in the field of infrared optical fiber communication devices and laser devices.This dissertation focuses on preparation and spectrum measurement of the PbSe QDF.(1) The PbSe QD doped UV gel is prepared by using a rotary evaporation method due to n-hexane, QDs and UV gel with different boiling points. Then, it is diluted to desirable concentrations in the laboratory. We measured the absorption and PL spectra of PbSe QD doped UV gel by using a Transmission Electron Microscopy(TEM), UV-visible Near-infrared Spectrophotometer and Fluorescence Spectrometer, and analyzing the absorption and PL spectra.(2) The QD doped UV gel with various doping concentrations is injected into the hollow fibers in the core diameter of 130 ?m by an air pump, and solidified with an UV light. By means of sealing, polishing the cross-sections of the fibers, the QDFs of solid core in various lengths and doping concentrations are prepared.(3) Using an optical power meter and near infrared spectrometer, we measure 980-nm pumping power and the photoluminescence(PL) spectrum varying with doping concentration and the fiber length, the measuring results show that the diameter of PbSe QD is 4.4 nm. Upon the pumping of 980 nm, the absorption coefficient of the QD doped fiber shows a linear relation with the doping concentration, and absorption cross section approximate to an exponential decrease with the increase of concentration, PL-peak intensity varying with the doping concentration and fiber length. The maximum peak intensity is determined with the doping concentration of 0.4 mg.mL-1 and the fiber length of 7 cm.The study presented in this dissertation suggests that the PbSe QDF taking UV gel as the background materials of fibers is an advisable technical way to develop novel QD doped fiber devices.