Full-Field Optical Coherence Tomography Based on a MII-4 Microprofilometer Using Microlenses with Air Immersion

A modernized Linnik microprofilometer (MII-4) allowing the performing of tomographic investigation of transparent and relatively turbid media by the methods of low-coherence interferometry has been presented. The design of the reference channel of the standard MII-4 has been revised. A dynamic adjustment of the reference arm length has been added to compensate for the effect of divergence between focal and coherent volumes, as well as spherical aberration that occurs when the optical system is focused into the deep layers of the object without the use of immersion microlenses. The analysis of the existing technical solutions of the reference arm designs has been carried out and their main drawbacks have been indicated. All stages of assembly and alignment of the complex have been described, and the device operation during visualization of transparent and turbid layered objects has been demonstrated.