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Quantum Optics

Author: the photonics expert Dr. Rüdiger Paschotta

Definition: the part of optics which deals with quantum effects

More general term: optics

Category: article belongs to category quantum optics quantum optics

DOI: 10.61835/stw Cite the article: BibTex plain text HTML Link to this page LinkedIn

Quantum optics is the part of optics (the science and technology of light) which deals with quantum effects. In many cases, such effects are studied in the context of fundamental research. However, they are also very important in laser physics:

Fundamental quantum-mechanical processes such as spontaneous and stimulated emission are of basic importance for the general operation and the performance of lasers.
Quantum effects introduce laser noise, e.g. cause a finite linewidth and a finite level of intensity noise even if all technical noise sources are suppressed. Similarly, they set a lower limit to the amplifier noise of optical amplifiers.

Another area of quantum optics involves nonclassical light, such as squeezed states of light, having unusual quantum noise properties. This area is somewhat related to the topic of quantum nondemolition measurements, which make it possible, e.g., to determine the intensity of a light beam without altering it.

Quantum Technologies

Quantum optics has practical applications, e.g. quantum cryptography, which is the use of quantum effects for secure transmission of information, and quantum metrology. Particularly the applied fields are also called quantum photonics as a field within quantum technology and within photonics. The following types of products are specific for those fields:

single-photon emitters
photon pair sources
low-noise photodetectors, e.g. for photon counting
optical traps
systems for quantum cryptography including quantum key distribution
parts for scientific research on quantum computing

More to Learn

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Suppliers

The RP Photonics Buyer's Guide contains six suppliers for quantum cryptography systems. Among them:

TOPTICA Photonics

Enabling quantum technology for demanding applications

When transferring scientific achievements into real life applications one needs an accompanying partner with expertise in fundamental research and industrial/oem capabilities. TOPTICA uniquely unifies both of these usually contradictory competences.

Coming out of the scientific quantum technology environment, TOPTICA has mastered the transition to a reliable and highly appreciated oem supplier. We still share the language, application know-how and passion with scientists but also understand and fulfill the specific requirements of industry.

TOPTICA is capable of converting scientific/research grade products into industry-grade instruments. And we are used to ramp-up production to high volumes. We can modify existing products or undertake new product developments and even higher level system integrations. So better choose the right partner right from the beginning!

Bibliography

[1]	D. L. Andrews et al., “Quantum electrodynamics in modern optics and photonics: tutorial”, J. Opt. Soc. Am. B 37 (4), 1153 (2020); https://doi.org/10.1364/JOSAB.383446
[2]	W. P. Schleich et al., Quantum Optics in Phase Space, Wiley-VCH Verlag GmbH, Weinheim (1999)
[3]	D. F. Walls and G. J. Milburn, Quantum Optics, Springer, Berlin (1994)
[4]	R. Loudon, The Quantum Theory of Light, 3rd edition, Oxford University Press, New York (2000)

(Suggest additional literature!)

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