Room temperature operating continuous wave terahertz light source via shallow electronic states transitions in semiconductors

基于半导体中浅能级光跃迁的紧凑型太赫兹光源已经研制成功，其性能得到了改善。已经使用Ge和其它各种半导体晶体。使用具有1微米波长的CW半导体激光器作为激发光源。可以确认通过浅能级的光学跃迁产生THz光。晶体温度依赖性的输出强度已经显示。在GaAs的情况下，通过1微米波长的光的低于间隙的激发可以成功地用于经由EL2能级的间接双光子激发过程。这种低于间隙的激励具有上级特征，因为均匀激励是可能的。特别是，THz输出的特定温度依赖性可以很好地理解鉴于光猝灭和光恢复效应的EL 2水平在GaAs中。利用THz带通滤波器对产生的THz波长进行了较好的估算。同时实现了边缘光激发的THz面发射特性。这一结果可以成功地应用于未来太赫兹激光器的太赫兹波长选择谐振腔结构。

Compact THz light source based on the optical transitions via shallow levels in semiconductors was successfully developed and those performances have been improved. Ge and other various semiconductor crystals have been used. CW semiconductor laser with 1 micron wavelength was used as an excitation light source. The generation of THz light via optical transitions by shallow levels can be confirmed. Crystal temperature dependences of output intensity have been shown. In case of GaAs, below gap excitation by 1 micron wavelength light can be successfully used for the indirect two photon excitation process via EL2 level. This kind of below gap excitation has a superior feature in that the homogeneous excitation can be possible. In particular, the specific temperature dependences of THz output can be well understood in view of the photoquenching and photo recovery effect of EL2 levels in GaAs. Generation THz wavelength was well estimated by using THz band pass filters. THz surface emission characteristics by edge light excitation was also realized. This result can be successfully applied for the THz wavelength selective resonant cavity constructions for future THz lasers.