We have studied the emission properties of combined intrinsic Josephson junction (IJJ) stacks. The IJJ THz oscillators were fabricated by two different methods : standard Ar ion milling and hydrochloric acid modification processes. We observed that the series connection of two stacks improves the heating problem. For the stacks with a large number of IJJs, intense emissions were observed only in the low-bias regime and it was found that such emission corresponds to the in- phase cavity resonance mode of a mesa. Furthermore, the obtained result showed the possibility of the synchronized emission from the series-connected stacks.
Yuimaru KuboYamaguchi TakahideTakayoshi TanakaShinya UedaSatoshi IshiiShunsuke TsudaATM Nazmul IslamIsao TanakaYoshihiko Takano
Shin–ichi KarimotoShugo KuboMikitaka ItohMinoru Suzuki
J. A. SternH. G. LeDucJ. Žmuidzinas