Polarization reference imaging systems: Basic principles

Oliver Graydon

Dong-Hoan Seo, Soo–Joong Kim

An improved image decryption system is proposed that is based on phase-encoded images and the principle of interference and uses a reference wave. A novel technique for generating intensity patterns from the decrypted phase information consists simply of interfering a reference wave with the wave passing through the encrypted image and a phase-only decrypting key. Optical experiments have confirmed the proposed technique as a simple and robust architecture for optical encryption.

D. Clarke, J. F. Grainger

Tsz Kit Yung, Hong Liang, Jiawei Xi +2 more

Two-photon interference is an important effect that is tightly related to the quantum nature of light. Recently, it has been shown that the photon bunching from the Hong-Ou-Mandel (HOM) effect can be used for quantum imaging in which sample properties (reflection/transmission amplitude, phase delay, or polarization) can be characterized at the pixel-by-pixel level. In this work, we perform Jones matrix imaging for an unknown object based on two-photon interference. By using a reference metasurface with panels of known polarization responses in pairwise coincidence measurements, the object's polarization responses at each pixel can be retrieved from the dependence of the coincidence visibility as a function of the reference polarization. The post-selection of coincidence images with specific reference polarization in our approach eliminates the need in switching the incident polarization and thus parallelized optical measurements for Jones matrix characterization. The parallelization in preparing input states, prevalent in any quantum algorithms, is an advantage of adopting two-photon interference in Jones matrix imaging. We believe our work points to the usage of metasurfaces in biological and medical imaging in the quantum optical regime.

T.S. Loth

Bose-Einstein condensates are interesting systems for studying quantum mechanics. Absorption imaging and phase-contrast imaging are two methods that are often used to determine the absolute number of atoms in a condensate. This thesis proposes a third method: holographic imaging. This method relies on the interference of a probe beam, which passes through the condensate, and a reference beam. The phase shift of the light due to the atoms and the optical density of the condensate are reconstructed with the use of Fourier transformation. Up to 300 images can be taken \\textit{in situ}.\n\nThere are two interesting applications of holographic imaging. The first is the refractive index, which can be measured directly with holographic imaging. The Hartree-Fock model is used to relate the real and imaginary part of the refractive index to the degeneracy of the condensate. However, the preliminary results are ambiguous and require further study.\n\nThe second is spin-dependent imaging, in which two orthogonally polarized reference beams are used to reconstruct polarization dependent information. This can be applied to study the dynamics of spinor condensates. In this thesis, a proof of concept for this method is given.