Remote control of heat nanosources motion and thermal-induced fluid flows by using light forces

November 22, 2020

Today, optofluidics is one of the most representative application of photonics for biological/chemical analysis. The ability of plasmonic structures (e.g., colloidal gold and silver nanoparticles, NPs) under illumination to release heat and induce fluid convection at the micro-scale has attracted high interest over the past two decades. Their size- and shape-dependent as well as wavelength-tunable optical and thermal properties have paved the way for relevant applications such as photothermal therapy/imaging, material processing, biosensing and thermal optofluidics to name a few. In-situ formation and motion control of plasmon-enhanced heat sources could pave a way for further harnessing their functionalities, especially in optofluidics. However, this is a challenging multidisciplinary problem combining optics, thermodynamics and hydrodynamics.

In a recent paper published in Light Science & Application, Professor Jose A. Rodrigo and co-workers from Complutense University of Madrid, Faculty of Physics, Department of Optics, Spain, have developed a technique for jointly controlling the formation and motion of heat sources (group of gold NPs) as well as of the associated thermal-induced fluid flows created around them. The scientists summarize the operational principle of their technique:

"The technique applies a structured laser-beam trap to exert an optical propulsion force over the plasmonic NPs for their motion control, while the same laser simultaneously heats up them. Since both the shape of the laser trap and the optical propulsion forces are easily and independently tailored, the hot NPs can be optically transported along reconfigurable routes with controlled speed according to the standing application."

They underline the main achievement:

"Based on this remote light-driven manipulation mechanism, we report the first evidence of thermal-induced fluid flow originated by a moving heat source with controlled speed along the target trajectory. This contactless manipulation of a fluid at the microscale provides a versatile optofluidic actuation enabling new functionalities, for example, to deliver nano-objects and analytes selectively to target locations as chemistry and biology research demand. Moreover, we experimentally demonstrate that the spatial and temporal control of the optical propulsion force allows changing the fluid streams as well as in-situ dividing/merging the dynamic group of NPs comprising the heat source. The reported results have fundamental and practical significance in the field of optical manipulation of nano-structures and thermal optofluidics. This is a nice example of the synergy between optical manipulation, thermoplasmonics and hydrodynamics."

The physicists envision: "The achieved combination of optical-induced heating of plasmonic NPs and their simultaneous programmable optical transport breaks ground for light micro-robotics and, in particular, for the creation of future thermal optofluidic tools."

Light Publishing Center, Changchun Institute of Optics, Fine Mechanics And Physics, CAS

Related Optical Manipulation Articles from Brightsurf:

Can memory manipulation help treat alcohol addiction?
BU researchers were able to artificially dampen fear responses in mice and mitigate addiction-related behaviors.

Common liverwort study has implications for crop manipulation
A new study on genetic pathways in the common liverwort could have future implications for crop manipulation.

Asymmetric optical camouflage: Tuneable reflective color accompanied by optical Janus effect
Deliverying viewing-direction sensitive information display across single sheet of transreflective window is introduced.

One more hit from rare Earth: Efficient coherent spin manipulation by the electric field
Researchers used rare earth ions to efficiently couple the electric and magnetic behaviors of material.

A survey on optical memory and optical RAM technologies
The ability to store with light and built promising optical memories has been an intriguing research topic for more than two decades.

Thermal manipulation of plasmons in atomically thin films
Nanoscale photothermal effects can induce substantial changes in the optical response experienced by the probing light, thus suggesting their applications in all-optical light modulation.

New discovery advances optical microscopy
New Illinois ECE research is advancing the field of optical microscopy, giving the field a critical new tool to solve challenging problems across many fields of science and engineering including semiconductor wafer inspection, nanoparticle sensing, material characterization, biosensing, virus counting, and microfluidic monitoring.

From digital to optical
Scientists have demonstrated how to create, using a femtosecond laser, an all-optical switch based on a metal-organic framework which can be synthesized in vitro and is usually used in chemistry for gas absorption.

All-fiber optical wavelength converter
Wavelength conversion in all-fiber structure has extensive applications in new fiber-laser sources, signal processing, and multi-parameter sensors.

Colliding solitons in optical microresonators
Solitons in optical microresonators are frequently used to generate frequency combs, which have found applications in sensing, telecommunication, and metrology.

Read More: Optical Manipulation News and Optical Manipulation Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to