297Thermal Nanosensors
have carved their niche because of the merits of noninvasivity, accuracy, and
robustness in even strong electromagnetic elds. Fluorescence is a process
distinct from incandescence (i.e., emission of light due to high temperatures).
Heating is generally detrimental to the process of uorescence, and most
substances, when uorescing, produce very little heat. Due to this reason,
uorescence has commonly been referred to as “cold light.” In the standard
conceptual model of molecules, the electrons occupy distinct orbits and thus
energy levels. When light falls on a molecule that absorbs rather than trans-
mits, one or more of the electrons of the molecule are “kicked” into a higher
energy state. All these excited elect