The autocollimator is an optical instrument for noncontact angle measurement with high resolution and a long detection range. It measures two-dimensional angles, i.e., pitch and yaw, but not roll. In this paper, we present a novelly structured autocollimator capable of measuring three-dimensional (3D) angles simultaneously. In this setup, two collimated beams of different wavelengths are projected onto a right-angle prism. One beam is reflected by the hypotenuse of the prism and received by an autocollimation unit for detecting pitch and yaw. The other is reflected by the two legs of the right-angle prism and received by a moiré fringe imaging unit for detecting roll. Furthermore, a prototype is designed and fabricated. Experiments are carried out to evaluate its basic performance. Calibration results show that this prototype has angular RMS errors of less than 5 arcsec in all 3Ds over a range of 1000 arcsec at a working distance of 2 m.

Curved compound eyes, i.e. microlens arrays on curved surfaces, are highly desirable for their unique optical properties including wide field of view, tracking of fast moving objects and so on. However, it is technically challenging to fabricate biomimetic gapless microlens arrays. In this work, we report a simple method for fabricating close-packed microlenses in a kind of stretchable polymeric material PDMS on curved surfaces inspired by the vertebrate eyes. The successfully fabricated polymeric curved compound eye consists of more than 6000 closepacked ommatidia with an average diameter of 600 µm for each ommatidium. The ommatidia are located on a convex surface with a diameter of 40 mm and thus a total field of view of about 180° has been obtained. The optical test on ommatidia shows that the NA for each ommatidium is about 0.21 and the imaging result of the whole compound eye is also given. Furthermore, an optical relay system is introduced to integrate with the compound eye to form a biomimetic compound eye camera. The formed camera is shown to have a great potential for a broad range of optical imaging applications, such as surveillance imaging, target detection and tracking, surveying and mapping, collision-free navigation of terrestrial and aerospace vehicles.

We investigate, through numerical calculation and experiments, the incoherent combination of a 2D Airy beam array (ICCAB) and the coherent combination of a 2D Airy beam array (CCAB), respectively. Excellent experimental results are obtained for both ICCAB and CCAB. The on-axis scintillation indices of ICCAB and CCAB at the receiver plane in atmospheric turbulence are also compared experimentally. It is shown that ICCAB has a smaller scintillation index than that of CCAB in the same turbulent condition due to the coherence reduction of the constituent beamlets. The results obtained in this paper are useful for the development of beam propagation through atmosphere turbulence.