Evaluation of a cheap ultrasonic stage for light source coherence function measurement, optical coherence tomography, optical coherence microscopy and dynamic focusing

We evaluate the performance of a cheap ultrasonic stage in setups related to optical coherence tomography. The stage was used in several configurations: 1) optical delay line in optical coherence tomography (OCT) setup; 2) as a delay line measuring coherence function of a low coherence source (e.g. superluminescent diode); 3) as a path length modulator in optical coherence microscopy (OCM) setup and finally 4) in a dynamic focusing arrangement. We evaluate each configuration and point to possible improvements either in setups or ultrasonic stage architecture. The results are as follows: the stage is suitable for coherence function measurement of the light source and, with some limitations, dynamic focusing. We found it unsuitable for OCT due to unstable velocity profile, while smaller step movement is required for OCM imaging