  The appearance of a Nano-jet in the micro-sphere optical experiments is
analyzed by relating this effect to non-diffracting Bessel beams. By inserting
a circular aperture with a radius which is in the order of subwavelength in the
EM waist, and sending the transmitted light into a confocal microscope, EM
fluctuations by the different Bessel beams are avoided. On this constant EM
field evanescent waves are superposed. While this effect improves the
optical-depth of the imaging process, the object fine-structures are obtained,
from the modulation of the EM fields by the evanescent waves. The use of a
combination of the micro-sphere optical system with an interferometer for phase
contrast measurements is described.
