Development of Biphoton Entangled Light Spectroscopy (BELS) using Bell pairs

Quantum Physics [Submitted on 23 Mar 2026] Development of Biphoton Entangled Light Spectroscopy (BELS) using Bell pairs V. V. Desai, N. P. Armitage We introduce Biphoton Entanglement Light Spectroscopy (BELS), a quantum spectroscopic technique that employs polarization entangled Bell pairs and two photon interference to probe material properties. In BELS, the measured signal arises not from single photon intensities but from changes in the joint polarization and path correlations of biphoton Bell pairs transmitted through or scattered by a sample and analyzed via cross channel coincidences. A key concept of BELS is the explicit mapping between Jones matrix operations and transformations within the Bell state manifold. Optical elements that are equivalent under classical polarization optics can produce qualitatively distinct signatures in the coincidence landscape when interrogated with entangled photons. We demonstrate that linear birefringence and Faraday rotation generate orthogonal admixtures of Bell states, yielding experimentally distinguishable coincidence channels within a single measurement. We measure birefringence in an anisotropic dielectric and Faraday rotation in \text{Tb}_3\text{Ga}_5\text{O}_{12}. By mapping the changes to the photonic entanglement, BELS establishes a new framework for future entanglement enhanced spectroscopy, a potentially powerful approach in characterizing quantum materials, nanophotonic devices, and light matter interactions perhaps eventually at a fundamentally quantum level. Comments: 9 pages, 5 figures Subjects: Quantum Physics (quant-ph); Materials Science (cond-mat.mtrl-sci); Optics (physics.optics) Cite as: arXiv:2603.22547 [quant-ph]   (or arXiv:2603.22547v1 [quant-ph] for this version)   https://doi.org/10.48550/arXiv.2603.22547 Focus to learn more Submission history From: Vishal Desai [view email] [v1] Mon, 23 Mar 2026 20:11:56 UTC (570 KB) Access Paper: HTML (experimental) view license Current browse context: quant-ph < prev   |   next > new | recent | 2026-03 Change to browse by: cond-mat cond-mat.mtrl-sci physics physics.optics References & Citations INSPIRE HEP NASA ADS Google Scholar Semantic Scholar Export BibTeX Citation Bookmark Bibliographic Tools Bibliographic and Citation Tools Bibliographic Explorer Toggle Bibliographic Explorer (What is the Explorer?) Connected Papers Toggle Connected Papers (What is Connected Papers?) Litmaps Toggle Litmaps (What is Litmaps?) scite.ai Toggle scite Smart Citations (What are Smart Citations?) Code, Data, Media Demos Related Papers About arXivLabs Which authors of this paper are endorsers? | Disable MathJax (What is MathJax?)