Development of super broad band, ultra-high sensitivity, ultra-wide field of view interferometer in milli-meter and submilli-meter wave bands

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Aim of our researches were development of a new type of millimeter and submillimeter interferometer which has much larger bandwidth, much higher sensitivity and much wider field of view compared with usually used interferometer in this wavebands. We have realized this type of interferometer by applying Martin-Puplett type Fourier transform spectrometer to aperture synthesis system. This is an concrete realization of the Michelson type bolometeric interferometer. Theoretical fundamentals were summarized in the paper published in Applied Optics. The results of laboratory experiments which had succeeded in obtaining source images in extremely broad band of 0.1THz-1.05THz in every 0.01THz simuletaneously was summarized in a paper which was submitted to Applied Optics. We have installed our instruments in Nobeyama Radio Observatory in where atmospheric condition is suited to millimeter and submillimeter observations and infrastructures for performing experiments are well developed. We have succeeded in observations of Sun in 0.1THz-0.36THz with our instrument. This is an extremely wide bandwidth compared with usual interferometer in this wavebands that is at most a few 0.01THz. PC control systems were developed and accuracies of pointing and guiding of astronomical objects were dramatically improved. Because of this improvement, we have recently succeeded in observations of Moon. We developed bolometer detectors which has a higher sensitivity than possible highest sensitivity of receiver used in usual interferometer. By installing this detector on our instrument, we have concluded that the sensitivity of our instrument is able to increase dramatically by reducing the noise originated from inside of our instruments by cooling down the whole instrument. The way of extending FOV of interferometer by applying detector array to our instruments were theoretically considered and proposed.