Quantum Optical Sensing

Quantum optical sensing is a technique that utilizes quantum mechanics to enhance, sensitivity and precision to a level considered unparalleled so far. This chapter attempts to introduce the reader to the basics of this fast-growing field along with various technologies and applications. It begins with an explanation of quantum mechanics, superposition, entanglement, and quantum coherence that allow sensors to go beyond classical performance. One of the central technologies is quantum entanglement – the phenomenon whereby several particles become instantaneous spouses and are measured with utmost precision, for instance, distance, time, and magnetic fields. Entanglement Interferometry is entanglement applied in the detection of gravitational waves and high-resolution imaging. Squeezed light, the other area of interest, is a method that removes some of the fluctuations in one parameter of light, to increase the interferometer sensor, to measure small movements and low-frequency gravitational waves. Single photon emitting devices and detectors enable high-sensitivity measurements in applications such as bioimaging and quantum-securing communication. The chapter also illustrates the usage of this technology in practice in healthcare, environment, and navigation, like the examination of biomarkers and pollutants. Last is the discussion of issues such as quantum coherence and issues of scalability and development of QTs, as well as the proposed further development and more potential advances for QTs as a medium for mass use.