【摘要】 以K2O为助熔剂,在较大的温度梯度(60～80℃/cm)条件下进行引种和晶体生长,应用坩埚下降法技术生长了Cr3+掺杂的近化学计量比的LiNbO3晶体。采用电感耦合等离子体原子发射光谱法(ICP-AES)分析了晶体的主要成分,其中Cr3+、Li2O、Nb2O3的含量分别为0.62mol%、49.23mol%和50.15mol%,并在FT-IR谱中观察到了因组分变化引起的OH-伸缩振动的变化。测定了晶体的吸收与发射光谱,观测到Cr3+在晶体中有两个宽且强的吸收带及两个微弱的吸收线,两宽带中心波长分别为480nm与658nm,对应于Cr3+的4A2→4T1与4A2→4T2两个具有相同的总自旋能级之间的跃迁,并观测到了微弱的684nm和728nm的R线吸收。同时测定了Cr3+∶LiNbO3晶体在670nm激发下的荧光光谱,是由4T2→4A2跃起所产生的850～1150nm的宽带荧光发射发光带,此发光带是由于取代Li+与Nb5+格位的Cr3+的4T2→4A2能级跃起的复合发光所致,并计算了该晶体的晶场强度以及Racah参数等。更多还原

【Abstract】 The near-stoichiometric LiNbO3 single crystals doped Cr3+ in the raw compositions were grown by Bridgman method using K2O as flux,and taking high temperature gradient of about 60~ 80 ℃/cm of the interface as seeding and growing of the crystal. The composition of as-grown crystal were analyzed by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES),the content of Cr3+,Li2O and Nb2O3 were 0.62 mol%、49.23 mol% and 50.15 mol%,respectively. The FT-IR indicated that stretching vibration of OH- changes as the composition changing. The absorption and fluorescence were also measured,two wide absorption band centered at 480 nm and 658 nm which corresponded to the 4A2→4T1 and 4A2→4T2 level transition,and two weak absorption of R-lines were at 684 nm and 728 nm were observed. The fluorescence spectrrum showed a emission wideband ranging from 850 nm to 1150 nm excited by 670 nm pulse laser in room temperature. It was to note that the wide emission assigned to the Cr3+Ni and Cr3+Nb transition of 4T2→4A2 level. The crystal field and Racah parameters were also calculated.更多还原