Quantum Theory of Light and Its Application

Yanhua H. Shih

In the beginning of 20th century, the successful introduction of the concept of light quantum, or photon, inspired a new foundation of physics, namely, the quantum theory. Today, quantum theory has turned out to be the overarching principle of modern physics. It would be difficult to find a single subject among the physical sciences which is not affected in its foundations or in its applications by quantum theory.

Gajendra Gadkar

The transmission of light through optical fibre has traditionally been governed by classical electromagnetic theory. However, increasing interest in quantum communication, quantum-limited amplification, and photonic quantum technologies necessitates a quantum mechanical treatment of guided light. This study presents a theoretical investigation into the application of quantum field theory and quantum noise models to light propagation in optical fibres. We formulate a quantized waveguide model, examine decoherence and photon statistics, and analyse implications for quantum communication and sensing. The results demonstrate that quantum theoretical approaches provide deeper insights into noise limits, entanglement preservation, and nonlinear photon interactions, offering pathways for next-generation quantum-enabled fibre networks.

Marc-Oliver Pleinert

Richard M. Sillitto

Jianjun Li

Spontaneous parametric down-conversion is a non-classical optical field,which is generated by the interaction on nonlinear crystal of monochromatic flux of pumping photons and quantum vacuum noise.In this paper,the generation mechanism of spdc light field is interpreted by theory of quantum mechanics;the interpretation by classical theory is also given here.The paper also introduces roundly the non-classical characteristics and application advances of spdc light field in laser,remote sensing and quantum communication.Last but not least,SPDC′s application prospect and its developing direction are also given in this paper.