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

[9410795] Gayen提出的研究目标是开发可调谐的固体激光器，它将在近紫外和蓝绿光谱区域工作。在三价稀土离子掺杂晶体中，由5d到4f的振动跃迁产生的强、宽波段荧光特别适合于这些波长的四能级激光操作模式。由于5d电子与宿主晶格强耦合，因此需要仔细选择活性离子（Ce3+, Pr3+）和宿主晶体来优化5d- 4f荧光，同时将激发态吸收的有害影响降至最低。利用吸收、激发和荧光光谱的性质、荧光寿命和强度提取与激光作用相关的关键光谱参数，如吸收和发射截面、振荡器强度、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。目标是能够制定这些晶体的选择和设计标准。该项目的成果将影响水下激光通信、光存储、细胞计数和生物技术等多个领域，以及用于放射成像的荧光粉和用于辐射探测的闪烁体的发展。＊＊＊

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. ***