We are advancing the measurement of dimension and function of engineered nanoparticles for biomedical research, manufacturing, and environmental health & safety impact studies through the development of validated physical measurement and particle manipulation methods.
Engineered nanoparticles are a key component of biomedical research, advanced manufacturing, and a major issue for environmental health & safety impact studies. The size and shape of nanoparticles provide the basis of their functional properties, so dimensional measurements of nanoparticles (NP) and complex NP assemblies are required to understand their behavior in changing environments. The primary goal of this project is to develop the necessary, sufficient, and validated physico-chemical measurement and particle manipulation methods that will enable nanoparticle-based applications to move forward.
Atomic force microscopy images of nanoparticle reference materials. Gold nanoparticles (left) and polystyrene latex spheres (right).
Trapping single particles allows particle properties and interactions to be precisely measured and enables the assembly of complex nanoparticle structures for applications in sensing, computation, and photonics. The ability to fully manipulate a particle’s position and orientation in three dimensions also offers new routes to test and fabricate nanodevices that may have no other path to manufacturing.
Levitating particles in air or vacuum provides nearly perfect isolation from environmental disturbance and allows precision measurement of dimension, shape, surface chemistry and optical properties of particles. These measurements can be made extremely sensitive by using surface resonances (whispering gallery modes or plasmons) of the light interacting with the particle.
Laser trapping of a 100 nm gold nanoparticle is improved by a factor of 20 under controlled conditions.
Trapping in water allows more effective manipulation of nanoparticles and intrinsic compatibility with the most highly developed methods of particle preparation, storage and transport. This also provides a natural interface to biological systems.
We have recently developed counter propagating beam-based traps to balance the optical scattering forces that destabilize particles in traps. This also improves trapping performance significantly, and may be used simultaneously with both the controlled trapping developed here, and ultra-resolution microscopy techniques developed in other labs.
This technique will be used to assemble and test nanophotonic devices that can not be made by other means, and to examine the emergence of quantum phenomena in plasmonic devices. This work also allows measurement of particle-beam interactions and metrology of the beam itself. The results highlight important aspects of the beams that are frequently neglected (such as the existence and behavior of cross-polarized components in linearly-polarized Gaussian beams) and are highly relevant to areas such ultra-resolution microscopy.
Start Date:January 29, 2010
Lead Organizational Unit:pml
100 Bureau Drive, M/S 8212