RESEARCH INITIATION AWARD: Short-Wavelength Tunable Solid-State Lasers

9410795 Gayen拟议研究的目标是开发工作在近紫外线和蓝绿光谱区域的可调谐固体激光器。三价稀土离子掺杂晶体中5d到4f振动跃迁产生的强宽带荧光特别适合于在这些波长下的四能级激光运转。由于5d电子与主体晶格的强耦合，为了优化5d-4f荧光，同时最小化激发态吸收的不利影响，应谨慎选择活性离子(Ce3，Pr3)和主体晶体。吸收光谱、激发光谱和荧光光谱的性质、荧光寿命和强度将被用来提取与激光作用有关的关键光谱参数，如吸收和发射截面、振子强度、辐射和非辐射衰减率以及谱线强度。将进行激光泵浦激光实验，以演示激光在有希望的晶体中的作用。将对输出特性、量子电子性质和损耗机制进行详细测量。我们的目标是能够制定这些晶体的选择和设计标准。该项目的成果将对水下激光通信、光存储、细胞学和生物技术等多个领域以及辐射成像用荧光粉和辐射探测用闪烁体的开发产生影响。***

9410795 Gayen The objective of the proposed research is to develop tunable solid- state lasers which will operate in the near-ultraviolet, and blue- green spectral regions. The strong, broad-band fluorescence that results from 5d-to-4f vibronic transitions in trivalent rare earth ion-doped crystals is particularly suitable for the four-level mode of laser operation in these wavelengths. Since the 5d electrons are strongly coupled to the host lattice, a careful choice of active ions (Ce3+, Pr3+) and host crystals would be used to optimize the 5d-to-4f fluorescence, and to simultaneously minimize the detrimental effect of excited-state absorption. The properties of the absorption, excitation, and fluorescence spectra, fluorescence lifetime and intensity would be used to extract key spectroscopic parameters which are pertinent to laser action, such as absorption and emission cross sections, oscillator strengths, radiative and nonradiative decay rates and line strengths. Laser-pumped lasing experiment would be conducted to demonstrate laser action in promising crystals. Detailed measurements of output characteristics, quantum electronic properties and loss mechanisms would be undertaken. The goal is to be able to formulate the selection and design criteria for these crystals. The results of this project would have an impact on such diverse areas as underwater laser communication, optical storage, cytometry and biotechnology, as well as the development of phosphors for radiologic imaging and scintillators for radiation detection. ***