Optical depth sectioning with quantum interferometry
Rojas Santana, Jorge Arturo
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The optical depth sectioning is a methodology to study the internal structure of semitransparent materials. Optical coherence tomography (OCT) is the standard technique for this purpose. Recent advances on OCT based on quantum principles transform the technique's physics, giving potential capabilities to develop more robust systems. OCT has demonstrated exceptional performance; however, the demand for increasingly precise systems encourages new developments. The challenge is to eliminate the effects that distort images, such as chromatic dispersion or low resolution. A potential solution is found in new OCT systems considering non-classical light sources, nonlinear interferometers, and singular photon detection systems. The development of these systems poses challenges in multiple aspects such as theoretical, experimental, and technical. This thesis gives three main contributions. The first is developing a detection methodology to use an oscilloscope as a cost-effective solution for counting and timing photons.The second contribution is a theoretical framework to realize optical coherence tomography using nonlinear interferometers such as OCT in an SU (1,1) interferometer, OCT based on induced coherence, and quantum-OCT working in the Fourier domain. We deduced general expressions for the output spectrum and focused our analysis on the particular case of a bi-layer sample. Our formulation allows us to perform a peer comparison, showing the main similarities and differences between the techniques. These results add valuable information to the growing body of literature concerning applications of nonlinear interferometers. Finally, we study an experiment of the induced coherence tomography to understand the role of the pump pulses in defining the spatial resolution of the system. We found the possibility of achieving high spatial resolutions and high emission rates by combining ultrashort pumping with millimeter-length crystals maintaining its advantageous features, i.e., probing the sample with a high-resolution ideal wavelength and using the optimum wavelength for detection.