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

本课题的研究目的是研制一种新型的毫米波和亚毫米波干涉仪，它与该波段常用的干涉仪相比，具有更大的带宽、更高的灵敏度和更宽的视场。我们将马丁-普普莱特型傅里叶变换光谱仪应用于孔径综合系统中，实现了这种干涉仪。这是迈克尔逊型测辐射热干涉仪的具体实现。理论基础在发表在《应用光学》上的论文中进行了总结。实验室实验成功地获得了0.1THz-1.05THz极宽波段的源图像，在每0.01THz的模拟中的结果总结在一篇提交给应用光学的论文中。我们在大气条件适合毫米和亚毫米观测的野边山射电天文台安装了我们的仪器，并且进行实验的基础设施非常发达。我们已经成功地用该仪器在0.1THz-0.36THz范围内对太阳进行了观测。这是一个非常宽的带宽相比，通常的干涉仪在这个波段，最多是几个0.01THz。开发了PC控制系统，天文目标的指向和引导精度得到了显着提高。由于这种改进，我们最近成功地观测了月球。我们研制的测辐射热计探测器，其灵敏度比通常干涉仪中使用的接收器可能的最高灵敏度更高。通过在我们的仪器上安装这种探测器，我们得出结论，我们的仪器的灵敏度能够显着增加，通过降低来自我们的仪器内部的噪声，通过冷却整个仪器。从理论上考虑并提出了将探测器阵列应用于我们的仪器中来扩展干涉仪视场的方法。

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.