Broadband Terahertz Frequency Multipliers

The spectral band from 1 - 5THz contains a wealth of information about the chemistry of the upper atmosphere and the structure and evolution of the Universe. The recent development of superconductive hot electron bolometers (HEBs) has made it possible for NASA to cover this frequency band with high-resolution heterodyne receivers with exceptional sensitivity. As a critical additional benefit, the HEB mixers require extremely low levels of local oscillator (LO) power. In fact system requirements of as little as one to ten microwatts make it feasible for the mixers to be pumped with solid-state sources based on a fundamental oscillator and a cascaded chain of frequency multipliers. However, multipliers for above 1 THz, even at these power levels, remain a formidable challenge. In fact, a frequency multiplier for Band 6 of the Heterodyne Radiometer for Herschel, spanning from 1,410 - 1,910 GHz, has not yet been demonstrated. Thus, the problem we propose to solve is the lack of a source of terahertz power suitable for preent and future NASA missions. This will be achieved through the use of our innovative and unique frequency quintupler circuit design and our proprietary GaAs-on-quartz circuit integration process.