Chen Xian, Jin Limin, Kong Wei, Sun Tianying, Zhang Wenfei, Liu Xinhong, Fan Jun, Yu Siu Fung, Wang Feng
Department of Physics and Materials Science, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong SAR, China.
Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR, China.
Nat Commun. 2016 Jan 7;7:10304. doi: 10.1038/ncomms10304.
Manipulating particle size is a powerful means of creating unprecedented optical properties in metals and semiconductors. Here we report an insulator system composed of NaYbF4:Tm in which size effect can be harnessed to enhance multiphoton upconversion. Our mechanistic investigations suggest that the phenomenon stems from spatial confinement of energy migration in nanosized structures. We show that confining energy migration constitutes a general and versatile strategy to manipulating multiphoton upconversion, demonstrating an efficient five-photon upconversion emission of Tm(3+) in a stoichiometric Yb lattice without suffering from concentration quenching. The high emission intensity is unambiguously substantiated by realizing room-temperature lasing emission at around 311 nm after 980-nm pumping, recording an optical gain two orders of magnitude larger than that of a conventional Yb/Tm-based system operating at 650 nm. Our findings thus highlight the viability of realizing diode-pumped lasing in deep ultraviolet regime for various practical applications.
控制颗粒大小是在金属和半导体中创造前所未有的光学性质的有力手段。在此，我们报道了一种由NaYbF4:Tm组成的绝缘体系统，其中可以利用尺寸效应来增强多光子上转换。我们的机理研究表明，该现象源于纳米结构中能量迁移的空间限制。我们表明，限制能量迁移是一种操纵多光子上转换的通用策略，证明了在化学计量比的Yb晶格中Tm(3+)的高效五光子上转换发射，而不会受到浓度猝灭的影响。在980 nm泵浦后，在311 nm左右实现室温激光发射，记录到的光学增益比在650 nm工作的传统Yb/Tm基系统大两个数量级，从而明确证实了高发射强度。因此，我们的发现突出了在深紫外区域实现二极管泵浦激光用于各种实际应用的可行性。
