THz emission characteristics from mesa arrays of Bi₂Sr₂CaCu₂O₈₊_δ single crystals

To develop the high power terahertz emission from Bi₂Sr₂CaCu₂O_8+δ (Bi2212) high-T_c superconducting THz emitters (Bi2212-THz emitters), it is very important to manage self- heating of these devices. We have developed stand-alone mesa structures (SAMs) of Bi2212 single crystals sandwiched by good thermal conducting sapphire substrates to reduce self-heating effects. These thermal managed devices enable us to extend the range of the radiation frequencies up to around 2.4 THz. For applications of THz emitters, 1 mW level of output power and 1 kHz level of radiation linewidth are required. In order to obtain such high performance characteristics from our Bi2212-THz emitters, we have studied not only about thicker SAMs but also arrays of SAMs. The SAMs up to around 8 μm thickness with keeping good shape of mesa structures can be obtained by a wet etching method so far. We made arrays of those SAMs by using the thermal managed device structures. At this moment, we observed about 10 μW level of output power from two arrays of SAMs with the dimensions of 69 × 190 × 4.2~4.4 μm³. The details of the current situation of our Bi2212-THz emitters will be discussed.