Preprint Article Version 2 Preserved in Portico This version is not peer-reviewed

The Quantum Regime Operation of Beam Splitters and Interference Filters

Version 1 : Received: 16 September 2019 / Approved: 17 September 2019 / Online: 17 September 2019 (12:47:42 CEST)
Version 2 : Received: 2 February 2023 / Approved: 2 February 2023 / Online: 2 February 2023 (11:24:04 CET)

A peer-reviewed article of this Preprint also exists.

Vatarescu, A. The Quantum Regime Operation of Beam Splitters and Interference Filters. Quantum Beam Sci. 2023, 7, 11. Vatarescu, A. The Quantum Regime Operation of Beam Splitters and Interference Filters. Quantum Beam Sci. 2023, 7, 11.


The presence of the quantum Rayleigh scattering, or spontaneous emission, inside a dielectric medium such as a beam splitter or an interferometric filter, prevents a single-photon from propagating in a straight-line. Modelling a beam splitter by means of a unitary transformation is physically meaningless because of the loss of photons. Additional missing elements from the conventional theory are: 1) the quantum Rayleigh stimulated emission which can form groups of photons of the same frequencies, and 2) the unavoidable parametric amplification of single-photons in the original parametric crystal. An interference filter disturbs, through multiple internal reflections, the original stream of single-photons, thereby confirming the existence of groups of photons being spread out to lengthen the coherence time. The approach of modelling individual, single measurements with statistical ensemble probability amplitudes leads to the counterintuitive explanations of the experimental outcomes and should be replaced with pure states describing instantaneous measurements which are afterwards averaged.


Quantum Rayleigh emissions, photonic beam splitters and interference filters, photon coincidence counting, HOM dip with independent photons.


Physical Sciences, Optics and Photonics

Comments (1)

Comment 1
Received: 2 February 2023
Commenter: Andre Vatarescu
Commenter's Conflict of Interests: Author
Comment: At least half of the first version's content has been published in reference [8] of this article.
New topics and analyses have been added based on recently published experimental results.
This version will be of interest to those working in the development of  photonic quantum systems and computing.
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