Researches on millimeter wave imaging in State Key Lab of Millimeter Waves are described. The researches mainly focus on the analysis and design of optical components or various lenses of imaging system. It is a base for getting good imaging quality. The field distribution in focal space of various lens including refractive lens and diffractive lens are analyzed and computed to show their imaging performance. The approaches to reduce the aberration of lens and expand the field-of-view of imaging system are studied and ameliorative results are obtained. Imaging experiment of concealed object is carried out to show the imaging ability of diffractive lens.

Bessel beams are a family of diffraction-free beams. They have many unique properties and prospective applications. Much attention has been focused to this subject in optics. Recently, the studies of such beams at mm- and submm- wavebands have been carried out in our group. The investigation results, including their theories, generation, propagation and potential applications, are presented in this paper.