新型中红外激光晶体Er^(3+)/Ho^(3+)/Eu^(3+)∶PbF_(2)的生长和性能

Growth and Properties of Novel Mid-infrared Laser Crystal Er^(3+)/Ho^(3+)/Eu^(3+)∶PbF_(2)

采用垂直布里奇曼法成功生长了Er^(3+)/Ho^(3+)/Eu^(3+)三掺杂PbF_(2)的中红外激光晶体。该晶体在980 nm泵浦下,首次获得了从2600~3200 nm的宽带中红外发光,其半高宽(FWHM)为300 nm,这是Er^(3+)的2.7μm发射峰(2600~2950 nm)和Ho^(3+)的2.9μm发射峰(2800~3200 nm)叠加的结果。此外,失活离子Eu^(3+)的引入可以有效克服Er^(3+)和Ho^(3+)离子的自终止瓶颈效应。研究发现,与Er^(3+)/Ho^(3+)∶PbF_(2)晶体相比,Er^(3+)/Ho^(3+)/Eu^(3+)∶PbF_(2)晶体具有更高的荧光分支比,在Er^(3+):^(4)I_(11/2)→^(4)I_(13/2)跃迁为18.7%和Ho^(3+):^(5)I_(6)→^(5)I_(7)跃迁为18.0%;以及有更大的发射截面,在2745 nm时为0.621×10^(-20) cm^(2),在2905 nm时为0.728×10^(-20) cm^(2)。这些有利的光谱特性表明,Er^(3+)/Ho^(3+)/Eu^(3+)∶PbF_(2)晶体在商用980 nm激光二极管泵浦下,可能是2.6~3.2μm中红外激光器的一种有前景的材料。

In this work,Er^(3+)/Ho^(3+)/Eu^(3+) tri-doped PbF_(2) mid-infrared laser crystal was successfully grown using the vertical Bridgman method.As far as we know,it is the first time to obtain a broadband mid-infrared luminescence extending from 2600 nm to 3200 nm with a full width at half maximum(FWHM)of 300 nm under 980 nm pump,which is the result of the superposition of the 2.7μm emission peak of Er^(3+)(2600-2950 nm)and 2.9μm emission peak of Ho^(3+)(2800-3200 nm).What's more,the introduction of deactivation ions Eu^(3+) can conquer self-termination bottleneck of both Er^(3+) and Ho^(3+) ions effectively.It is found that,compared with the Er^(3+)/Ho^(3+)∶PbF_(2) crystal,the Er^(3+)/Ho^(3+)/Eu^(3+)∶PbF_(2) crystal has higher fluorescence branching ratio 18.7%of Er^(3+):^(4)I_(11/2)→^(4)I_(13/2) transition and 18.0%of Ho^(3+):^(5)I_(6)→^(5)I_(7) transition,and larger emission cross section 0.621×10^(-20) cm^(2) at 2745 nm and 0.728×10^(-20) cm^(2) at 2905 nm.These advantageous spectroscopic characteristics suggest that the Er^(3+)/Ho^(3+)/Eu^(3+)∶PbF_(2) crystal may be a promising material for 2.6-3.2μm mid-infrared lasers under the pump of a commercial 980 nm laser diodes(LDs).