The Studies On Femtosecond Coherent Spectroscopy And Nonlinear Optical Properties Of Several New Optical Materials

The femtosecond coherent spectroscopy and coherent control are coming out as scientific research hot-spots in recent years. Although the work of the coherent control is conducted most extensively in chemistry, the most possible application of the field is expected to be in optoelectronics. Rare-earth (RE) solid is among the most widely used materials in optoelectronics. However, it is rarely reported on the systematic investigations for the femtosecond coherent spectroscopy on rare earth ions. On the other hand, coherent control has been applied to gas, liquids, semiconductor quantum well and crystal. However, it is difficult to apply this technique to disordered solids because of fast-dephasing nature in them. Up to now, no result has been reported about the temporal coherent control in the disordered solids. Moreover, Due to the present development of optoelectronics, it becomes essential to prepare the new material and investigate its nonlinear optical properties. So, the relative research in the new materials are important to both fundamental and applied research.The thesis deals with two respects of new materials: 1) the femtosecond coherent spectra and the coherent control with femtosecond optical pulses. The femtosecond coherent spectra include free-induction decay (FID) and photon echo. 2) Other nonlinear optical properties including photon avalance upconversion and optical limiting. The main contents are as following.Firstly, coherent spectra of free-induction decay (FID) are studied for ZnO-Nb₂O₅-TeO₂:Er₂O₃ at room temperature using femtoseeond laser pulses with the excitation wavelength of 800 nm. Coherent dephasing times of 300 fs are measured. Moreover, frequency upconversion spectra are studied in the FID experiment. It is observed that the quantum yield efficiencies for the upconversion can be manipulated by controlling the delay time between the two laser pulses. The coherent control is successfully applied to the ZnO-Nb₂O₅-TeO₂:Er₂O₃ at room temperature which is the first time for coherent control to be applied to the disorded solid. The coherent-control all-optical switching based on ZnO-Nb₂O₅-TeO₂:Er₂O₃ is proposed.Secondly, coherent spectra of photon echo are studied for...