Reflection based highly nondegenerate Bi-photon HOM interferometry
A thesis on setup design and Fisher information based optimization
F.A.W. Looman (TU Delft - Applied Sciences)
S.F. Pereira – Mentor (TU Delft - ImPhys/Pereira group)
A.J.L. Adam – Graduation committee member (TU Delft - ImPhys/Adam group)
S. Stallinga – Graduation committee member (TU Delft - ImPhys/Stallinga group)
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Abstract
The goal of this thesis is to investigate the viability of reflection-based biphoton Hong-Ou-Mandel Interferometry (HOMI) for measuring a sub-nanometer step size. We attempt to push this technology forward by designing for larger separation than has been done before in the literature, resulting in higher possible precision.
This is a Fisher-information-based estimation method. We show that the Quantum Cramér-Rao (QCR) bound can be saturated with our proposed measurement. We propose a mostly common-path interferometer design, where the two optical paths are distinct in polarization instead of spatial mode. This reduces the risk of creating accidental which-path information.
For the production of the photon superposition, we propose a novel biphoton source design specialized for large detuning between the two downconverted wavelengths, similar to the more common beamdisplacer entangled photon sources. The proposed photon source can be designed for type-0 and type-II SPDC.
We suggest a detection system based on a combination of visible and NIR single-photon detectors to handle larger detunings than is possible with a single type of detector. The best combination of detectors and type of SPDC was Si-SPAD (visible) and SNSPD (NIR) with weak downconversion focusing (ξ ≪ 1).
This experiment has an expected measurement time of 7.4 seconds for 0.1 nm precision. We conclude that biphoton HOMI is indeed feasible for high-precision metrology.