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

9410795 Gayen拟议的研究的目的是开发可调谐固态激光器，将在近紫外线和蓝-绿色光谱区工作。 在三价稀土离子掺杂晶体中，由5d到4f的电子振动跃迁产生的强宽带荧光特别适合于这些波长的四能级激光操作模式。 由于5d电子强烈耦合到主晶格，因此将使用活性离子（Ce 3+，Pr 3+）和主晶体的仔细选择来优化5d到4f荧光，并同时最小化激发态吸收的有害影响。 吸收，激发和荧光光谱，荧光寿命和强度的属性将被用来提取关键的光谱参数，这是相关的激光作用，如吸收和发射截面，振子强度，辐射和非辐射衰减率和线强度。 将进行激光泵浦激光实验，以证明激光在有前途的晶体中的作用。 将对输出特性、量子电子特性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、细胞计数和生物技术等不同领域产生影响，并对放射成像荧光粉和辐射探测荧光剂的开发产生影响。 ***

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. ***