Construction and test of a GRIN-based optical objective.

Optical fibres with their unique ability to transport light even in a coherent way (fibre bundles) and the possibility to build small volume optical pieces (Graded Index Fibres, GRIN) have a dominant role in the assembly of probes and objectives for microscopy applications requiring noninvasive and flexible operation in small and crowded spaces (in vivo microscopy, endoscopy, inspection). Nowadays, even complex observing procedures like confocal, two-photon and optical coherence tomography can be approached with fibres, making possible in vivo applications and also in place decision and processing. We present here a series of analytical simulations and practical tests made on an experimental GRIN fibre objective light fed through an adaptive optics system aimed to verify the practical possibility to correct a focalized beam of light. We intend this as a first step to the implementation of non-invasive probes making use of forthcoming optical devices (scanners, deformable mirrors) based on MEMS technology.