Photons in Natural and Life Sciences

Sergio Carbajo

Photon sciences and technologies establish the building blocks for myriad scientific and engineering frontiers in life and energy sciences.In this perspective article, we map current and emerging linkages between three intersecting areas of research stewarded by advanced photonics technologies, namely light by design, outlined as (1) quantum & structured photonics, (2) light-matter interactions in accelerators and accelerator-based light sources, and (3) ultrafast sciences & quantum molecular dynamics.In each section, we will concentrate on state-of-the-art achievements and present prospective applications in life sciences, biochemistry, quantum optics and information sciences, and environmental and chemical engineering, all founded on a broad range of photon sources and methodologies.

Robert M. Bunch

Christopher C. Gerry, Kimberley M. Bruno

This chapter begins by explaining why physics is the fundamental of all natural sciences. Throughout most its history, atoms were hardly the center of attention in physics. Once called natural philosophy, physics originated in the study of the motion of inanimate objects. From those studies emerged a body of knowledge, including various natural laws, that today we call ‘classical’ physics. Newton's laws of motion, the basis of the science of mechanics, come to mind, as does his law of universal gravitation. These laws are obeyed by objects that in some sense are ‘large’ and, in fact, the laws were discovered after careful observation of the behavior of such objects. The discussion then turns to the focus of the book—the quantum world—where the laws of physics turn out to be different from the laws of classical physics used to explain phenomena in the macroscopic world of everyday life. The book discusses a number of mostly recent experiments on quantum mechanical foundations, most of them involving light at the level of a few photons—sometimes only one.

Geoffrey Hunter, Robert L. P. Wadlinger

Aleksei M. Zheltikov, Marlan O. Scully

Abstract Quantum entanglement is a powerful resource that revolutionizes information science, opens new horizons in communication technologies, and pushes the frontiers of sensing and imaging. Whether or not the methods of quantum entanglement can be extended to life-science imaging is far from clear. Live biological systems are eluding quantum-optical probes, proving, time and time again, too lossy, too noisy, too warm, and too wet to be meaningfully studied by quantum states of light. The central difficulty that puts the main roadblock on the path toward entanglement-enhanced nonlinear bioimaging is that the two-photon absorption (TPA) of entangled photons can exceed the TPA of uncorrelated photons only at the level of incident photon flux densities as low as one photon per entanglement area per entanglement time. This fundamental limitation has long been believed to rule out even a thinnest chance for a success of bioimaging with entangled photons. Here, we show that new approaches in nonlinear and quantum optics, combined with the latest achievements in biotechnologies, open the routes toward efficient photon-entanglement-based strategies in TPA microscopy that can help confront long-standing challenges in life-science imaging. Unleashing the full potential of this approach will require, however, high throughputs of virus-construct delivery, high expression efficiencies of genetically encodable fluorescent markers, high-brightness sources of entangled photons, as well as a thoughtful entanglement engineering in time, space, pulse, and polarization modes. We demonstrate that suitably tailored nonlinear optical fibers can deliver entangled photon pairs confined to entanglement volumes many orders of magnitude smaller than the entanglement volumes attainable through spontaneous parametric down-conversion. These ultracompact modes of entangled photons are shown to enable a radical enhancement of the TPA of entangled photons, opening new avenues for quantum entanglement in life-science imaging.

Chandrasekhar Roychoudhuri