Abstract: A fiber optic needle probe is described that includes a length of optical fiber inside a hollow needle for supporting the optical fiber along its length. A distal end of the optical fiber is formed by a formed convex tip protruding beyond a distal end of the hollow needle. The distal end of the optical fiber is formed by a formed conical tip with a cone angle less than hundred degrees. The shape of the convex tip formed at the distal end of the optical fiber is found particularly suitable for repeated insertion into a tissue with minimal tendency of tissue residue sticking to the tip.

Abstract: A bidirectional fiber optic probe comprises an optical in/out coupler and a single fiber or a bundle of fibers, each fiber having a proximal end and a distal end and a numerical aperture NA=sin ?. The numerical aperture NA describes the range of angles over which the optical fiber's proximal end can accept or emit light. The numerical aperture depends on the refractive index n of the fiber core and is given by NA=n sin* ?. ? is the acceptance angle being defined as the half angle of the acceptance cone of the fiber at its proximal end.

Abstract: A bidirectional fibre optic probe comprises an optical in/out coupler and a single fibre or a bundle of fibres, each fibre having a proximal end and a distal end and a numerical aperture NA=sin ?. The numerical aperture NA describes the range of angles over which the optical fibre's proximal end can accept or emit light. The numerical aperture depends on the refractive index n of the fibre core and is given by NA=n sin* ?. ? is the acceptance angle being defined as the half angle of the acceptance cone of the fibre at its proximal end.