Laser coarse–fine coupling scanning method by steering double prisms

Abstract

Recent developments in optical communication systems have presented an emerging need for scanning and tracking dynamic targets with high accuracy. Unfortunately, conventional scanners have difficulty supplying either sufficient vision information or high scanning resolution because of the fixed optical parameters and optomechanical structure. This paper introduces a novel cascaded double-prism scanner that combines the two scanning modes of rotating and titling motions into a nested device. The analysis results show that both the vertical field angle range and the horizontal field range of the coarse scanning are no less than ±10°, with the scanning accuracy superior to 50 μrad, while the vertical field angle range and the horizontal field range of the fine scanning are, respectively, no less than 2500 μrad and 1200 μrad, with the scanning accuracy superior to 1 μrad. The scanning method not only meets the requirements of collaboratively steering the beam deviation in a large range with high accuracy but also can obtain a variety of scanning modes and trajectories, which has important engineering significance for the solution of steering a fine beam to track and position a dynamical target.

Handheld scanning probes for optical coherence tomography: developments, applications, and perspectives

“…Other types of handheld probes are in development in our groups, with 2D GSs [43], while different types of scanning devices are being explored to be included in such probes, especially Risley prisms -rotational [44,45] or oscillatory [46].…”

Laser scanners: from industrial to biomedical applications

“…The device has two (rarely three) prisms -usually optical wedges with the prism angle of up to 10°. The wedges are usually rotational [33][34][35][36][37][38][39][40], but tilting solutions [41] or combinations of rotational and tilting prisms [42] have also been explored, while we have developed a device with translational wedges for precise optical attenuation [52].…”

“…(2) refractive: with Risley prisms (double optical wedges) that are rotational [33][34][35][36][37][38][39][40], tilting [41], or in combination of those [42]; scanners with lenses are rarely used, although such solutions exist;…”

Comparison of refractive rotating dual-prism scanner used in near and far field

“…In the mechanism of universal rotating mirror, the steering of beam or optical axis is implemented by quickly wiggling the scanning mirror mounted before the laser or the detector. This kind of mechanism is only applied to the deflection of small-aperture beam since it usually takes up too much space and the deflection of beam is very sensitive to mechanical errors [7]. The rotating dual-prism scanner, in which the direction of beam is changed by rotating two prisms along the same axis independently to achieve the steering of beam or optical axis, is a simple and potential method for adjustment and scanning of beam pointing.…”

“…Communication beam usually transmits between two remote dynamic targets and high accuracy of beam pointing is one of the important factors that affect system performance [7]. Using rotating dual-prism scanner to accomplish long-distance target detecting and tracking instead of traditional system such as universal rotating bracket and universal rotating mirror can not only meet the requirements of large-aperture beam deflection to realize stable pointing with high resolution, but also make the system more compact and convenient for the structure design and installation of carrier platform.…”