9303448 Sardar Research on this grant aims to investigate the optical properties of rare earth ions doped in crystalline host materials using the techniques of laser spectroscopy. Two important neodymium-based single crystals: YVO4:Nd3+ (1 %) and CaMgZnY2Ge3012:Nd3+ (2%) will be studied initially. There have been some studies on the first material, but none on the second. In the final phase of the project, a more complex, triply-doped material: YAG: Cr3+ (1%), Tm3+ (5%), Ho3+ (1%) will be investigated. A complete and systematic spectroscopic investigation of these materials will be performed, their optical and laser properties will be compared with those of existing laser materials, and the potential of these materials as lasers will be evaluated. The measurements will include absorption, emission, and excitation spectra and fluorescence lifetimes at different temperatures. %%% These materials have received much attention in recent years since their emission wavelength falls in the 2um range, which has proven to be very attractive for a number of medical applications because of the strong water absorption at this wavelength. The 2.1um 5I7 - 5I8 laser transition in Ho3+ is attractive because of its long upper laser level lifetime, of the order of 5 ms, permitting larger energy storage than Nd:YAG, and its eye-safe wavelength. Study of the important mechanism of energy transfer from Cr3+ to Tm3+ and finally to Ho3+ in this crystal will provide an excellent educational experience for undergraduates involved in the project; this grant is part of NSF's Research in Undergraduate Institutions(RUI) activity. The proposed work is in an area of current scientific interest in the field of photonics, is technologically relevant, and has excellent potential to provide a rewarding educational opportunity for the participating undergraduates who will be exposed to modern spectroscopic equipment, techniques, and theories. ***
