Temperature Influence On Photoluminescence And Optical Properties Of PYN-PLZT Ceramics

Electrooptic ceramic PYN-PLZT is the solid solution of PYN and PLZT, the transparency remains high when high concentration of Yb3+ ions is high. The high concentration of Yb3+ make it promising in making multifuncational light sources(lasers and optical amplifiers). Because Yb3+ ions possess only two manifold 4f energy levels, the excited state absorption, transformation and concentration quenching effect do not exist, which are the important factors adversely influencing the Nd3+ ions laser performance. Besides, Yb3+ ions possess longer level lifetimes, which are highly desirable in developing high power lasers. All these merits associated with are behind the intensive research and development activities with Yb3+ ions based gain media in recent years. Owing to the Yb3+ ions’ quasi-three level feature, the laser material performance was influenced greatly by ambient temperature. To analyze the influence, this work focuses on varying of luminescence of PYN-PLZT ceramics with temperature. The aim of the work is to seek an appropriate working wavelength for lasers and amplifiers under different temperature, and to offer the theoretical guidance in improving the performance of the Yb3+ ions doped laser materials. To know the potential of electrooptic PYN-PLZT ceramic in making multifunctional light sources(lasers and optical amplifiers), we studied its optical, electrical, thermal and light emission properties and also explored the impact of elevated temperature on some associated properties.The transmission spectrum of the material was measured to know the spectral range and capability of the host material-PYN-PLZT. After this, dielectric constants vursus temperature was measured experimentally, from which Curie temperature was determined. The quadratic electro-optic coefficient of material was measured with single beam methodology, along with temperature stability of the material. The high transparency in the waveband of interest revealed its suitability as host materials in making light sources. The relatively broad ferroelectric spectrum implied the much relaxed temperature control to the circuit. The high electrooptic coefficient over abroad temperature range guaranteed low applied voltage.To get an idea about the phonon modes and absorption peaks in the PYN-PLZT ceramic material host material, we obtained the Raman spectrum and absorption spectrum. Through the measurement, we understood the material internal lattice vibration levels, which is key in understanding the thermal properties of the gain medium, and determined appropriate pump wavelength. Several key factors, such as absorption cross section, spontaneous emission coefficient and the stimulated emission section were evaluated by the expanded J-O theory. Variation of luminescence of gain medium with the temperature was discuss ed theoretically.To learn the suitable waveband and associated thermal feature, in the last part of the work, the photoluminescence spectrum was measured while the temperature was changed. The quasi-three level system was evaluated using the "energy level" theory which deals the laser materials. Based on the experimental results obtained, light emission dependence on temperature were discussed in details. All these works help us determine optimal waveband in developing light sources with the gain medium.