Multiple Projection Laser Microscopy in the Ulbricht Integrating Sphere (MPLM-UIS) using lens-less microscopes with CCD and CMOS (active-pixel) sensors, including angle sensitive ones.

Abstract

Microscopy with an integrating sphere (also known as the photometric Ulbricht sphere) is rarely used in histological and cytological practice due to the difficulties in manufacturing the integrating chamber with the technological holes for the sample placing, as well as the high cost of the modern commercially available Ulbricht spheres. The additional difficulties appear at the ultrastructural / submicroscopic level, especially when using near-field optical microscopy (SNOM) techniques determining the size of the integrating sphere. The required correspondence between the radius of the integrating sphere and the size of the specific sample / sample stage results in a physical and technical contradiction, which in principle can be overcome only if a number of conditions are met. The first and obvious one is the equal dimensions of the transmission window of the sample stage and the sample itself. The final condition is obtaining a wide-field image at the stationary position of the stage, since its displacement inside the integrating sphere will lead to the changes in the light-shadow (schlieren) structure of the registrogram. The same is true for the movement of the coordinate stage or a slide / sample itself, but for the sample in vivo / in situ perturbations of the optical field of the isotropic-integrating sphere can be used as an analytical signal. In a general case, when all the above planes and sections are located at the stationary position at the center of the Ulbricht sphere, the only possible solution is to use CCD / CMOS sensors with a simple printed circuit board, which act as an analytical chip with a function of a lensless projection microscope instead of the reduced conventional optical microscope.