Think small: developing color centers in crystals for nanoscale optical sensors of fields and forces
Friday, April 12 | 12:00pm | Elings 1605
From mapping inter-cellular mechanical interactions in the immune system to imaging magnetic phenomena in condensed matter systems, there is a growing need for noninvasive sensors with high spatial resolution. Color centers in crystals such as alkaline-earth upconverting nanoparticles (UCNPs) and the nitrogenvacancy (NV) center in diamond are an exciting class of sensors for highresolution imaging because of their optical readout, nanoscale size, and robust hosts. The first part of this talk will discuss UCNPs for mechanical force sensing in biological applications. UCNPs consist of a ceramic host doped with lanthanides (Yb3+ and Er3+). They operate by absorbing low energy infrared photons and emitting higher energy visible photons. Mechanical forces cause a change in the crystal symmetry and spacing of the dopant atoms, which results in a change of emission intensity and color. We have recently detected 27 nN forces with our UCNPs, a requisite for detecting inter-cellular forces in the immune system. The second half of this talk will discuss using the NV center in diamond as a magnetic force sensor. Through careful materials science studies in the Jayich lab, we created NV ensembles approaching the NV dipolar interaction limit of sensitivity. Using these NV ensembles, we imaged magnetic structure in CoTiSb.