A radial sine phase filter is introduced in optical systems to control and alter the optical system focusing properties with incident Gaussian beam. It was found that the radial sine phase filter can induce tunable multiple foci in focal region, which means that the several field distances can be imaged clearly simultaneously with this kind of filter in imaging optical system. And the point of absolute maximum intensity does not coincide with the geometrical focus but shifts along the optical axis; this phenomenon is referred to as focal shift. Focal shift distance and direction can be altered by a sine parameter in the sine term of the phase distribution function. In addition, focal shift may be accompanied by an effective permutation of the focal point, namely, maximum intensity can jump from one position to other position for certain sine parameter, this effect is referred to as focal switch, which also can also be used to adjust imaging clearly field distance in-continuously. The radial sine phase filter can adjust and optimizing the focusing and imaging properties of the optical systems considerably, waist width and section shape of incident Gaussian beam also affect multiple foci.

Date Published: 30 October 2009
PDF: 6 pages
Proc. SPIE 7497, MIPPR 2009: Medical Imaging, Parallel Processing of Images, and Optimization Techniques, 74970K (30 October 2009);

Published in SPIE Proceedings Vol. 7497:
MIPPR 2009: Medical Imaging, Parallel Processing of Images, and Optimization Techniques
Faxiong Zhang; Faxiong Zhang, Editor(s)