We report on a conceptual design and feasibility demonstration for a scanned beam endoscope, with advantages over present CCD imaging technology in image resolution and quality, light source power, and package diameter. Theoretical calculations were made by optical modeling and finite element analysis of the performance projected for a design meeting size constraints. To verify the design target of 5 mm for the endoscope diameter, we conducted a design study of the deformation and resolution characteristics of a scan mirror small enough to fit within a 2.5 mm capsule within the endoscope. The results show that performance similar to the test system can be achieved. A functional prototype was then built and tested to validate the theory used. The test system consisted of a photonics module with red (635 nm), green (532 nm) and blue (473 nm) lasers, combined by dichroic mirrors and launched to a single mode fiber. The light emerging from the fiber is formed into a beam and reflected from a commercially available bi-axial MEMS scanner with a 1.56 mm square mirror, and a scan angle of 6 degrees zero to peak mechanical, at a frequency of 19.7 kHz. Scanned beam power from 1 to 3 mw impinges the test object at a range from 10 to 100 mm, and the scattered light is collected by several 3 mm diameter multimode fibers and conducted one-meter to detectors. The detected light was digitized and then reconstructed to form an image of the test object, with 800 by 600 output pixels. Several such images will be presented.
An optical configuration and measurement algorithm are outlined for producing semi-automated Near to Eye Display measurements of the Michelson Contrast versus varying spatial frequencies. The input patterns measured include line on-line off (LOLO) images from a single LOLO to eight LOLO, in both the horizontal and vertical direction. These measurements result in a Contrast Transfer Function of the display under test, revealing information on the image quality of the display system.
Uncertainty in tip morphology of aluminum coated, fiber-optic near-field probes, and the large difference between the physical probe diameter and (smaller) optical diameter, lead to serious imaging artifacts in transmission mode near-field microscopy. Various dielectric materials of different topographies have been studied to develop an understanding of normal and anomalous contrast modes mainly characterized by topographically induced contrast.