Full-field optical coherence tomograph based on MII-4 micro interferometer with air-immersion objectives

A modernized Linnik micro profilometer (MII-4) is introduced for the tomographic studies of transparent and relatively turbid media using air-immersion objectives. The construction of the reference channel in standard MII-4 is reworked by adding the dynamic adjustment of reference arm length to compensate for the effect of the divergence between focal and coherent volumes, as well as spherical aberration arising from the focusing of the optical system into the deeper layers of an object without using immersion. An analysis of existing technical solutions for the reference arm is done, their main disadvantages are indicated. All stages are described including assembling and adjusting the system. The device was able to perform a tomographic studies transparent and turbid layered objects.