True-spectroscopic dual mode high resolution full-field optical coherence tomography using liquid crystal devices

An interference microscopy three dimensional imaging system comprising:

• a) a light source;
• b) a diffuser adapted to diffuse light received from the light source;
• c) a condenser lens adapted to condense diffused light received from diffuser;
• d) one of an aperture stop or an optical mask adapted to extend the depth of field of the objective lenses of a sample arm and a reference arm of said system respectively;
• e) a field stop;
• f) a projecting lens adapted to image one of aperture stop or optical mask to the back aperture planes of objective lenses and to image field stop to the plane of the object and to the plane of reference mirror;
• g) a linear polarizer adapted to polarize the light transmitted through projecting lens;
• h) a liquid crystal tunable filter adapted to receive light that has passed through linear polarizer;
• i) a first voltage supply unit adapted to control liquid crystal tunable filter;
• j) a beam splitting device adapted to split the light passing through tunable filter into two beams;
• k) achromatic quarter wave plates in the reference and sample arms, respectively, the achromatic quarter wave plates adapted to rotate, upon double pass, the linear polarization of the transmitted light by 90°,
• l) a dispersion compensating plate inserted in the reference or sample arm of the system;
• m) a liquid crystal retarder (LCR) positioned in one of the following locations:
• before the polarization beam splitter or after the beam splitter in either the sample arm or in the reference arm;
• wherein, when positioned before the polarization beam splitter, the LCR is adapted to align the extraordinary axis 45 degrees with the direction of the incident polarization and, when located after the beam splitter, the LCR is adapted to align the extraordinary axis with the direction of the incident polarization;
• n) mirrors in the reference arm, the mirrors adapted to direct light from beam splitting device through objective lens and back to beam splitter;
• o) a mirror in the sample arm, the mirror adapted to allow a sample to be attached to its front surface and to direct light from beam splitting device through objective lens and back to beam splitting device;
• p) an analyzer adapted to receive the two beams returning from mirrors and sample after they are recombined by passing through beam splitting device;
• q) a tube lens adapted to receive an interference signal from analyzer;
• r) a parallel detector adapted to receive the interference image projected onto it by tube lens;
• s) a motorized stage adapted to scan sample mirror;
• t) a controller adapted to control motorized stage;
• u) a second voltage supply adapted to control liquid crystal retarder;
• v) a TTL unit adapted to control first voltage supply unit, second voltage supply, and controller;
• and
• w) a PC connected to TTL unit.