Dual-beam heterodyne Fourier domain optical coherence tomography

We report on a novel method combining achromatic complex FDOCT signal reconstruction with a common path and dual beam configuration. The complex signal reconstruction allows resolving the complex ambiguity of the Fourier transform and to enhance the achievable depth range by a factor of two. The dual beam configuration shares the property of high phase stability with common path FDOCT. This is of importance for a proper complex signal reconstruction and is in particular useful in combination with handheld probes such as in endoscopy and catheter applications. The advantage of the presented approach is the flexibility to choose arbitrarily positioned interfaces in the sample arm as reference together with the possibility to compensate for dispersion. The method and first experimental results are presented and its properties concerning SNR and dynamic range are discussed.