Fluorescent Nanodiamonds

11Nanoscale Quantum Sensing

Richard Feynman predicted in his 1959 speech, There’s Plenty of Room at the Bottom (Section 1.1), “When we get to the very, very small world – say circuits of seven atoms – we have a lot of new things that would happen that represent completely new opportunities for design. Atoms on a small scale behave like nothing on a large scale, for they satisfy the laws of quantum mechanics. … We can use, not just circuits, but some system involving the quantized energy levels, or the interactions of quantized spins, etc.” [1]. Indeed, 60 years later, Feynman’s “quantized spins” is today’s quantum reality.

As the name suggests, a nanoscale sensor (or nanosensor) is a device that can detect events or changes in its surrounding environment at the nanoscale or within a distance range of 1–1000 nm. The events or changes detected may be physical, chemical, or biological in nature. Examples of the use of nanosensors in the life sciences include high‐sensitivity detection of DNA and measurement of local temperature changes in living cells. In order to serve as an effective nanosensor, the device must be smaller than 100 nm and the output signals should be detectable with high sensitivity, preferably, at the single molecule or particle level. Once properly conjugated with biologically important molecules or other functional nanomaterials, these devices can be designed for use in nanomedicine such as to identify and destroy cancer cells as well as repair abnormal or ...