Frequency-Specific Optical Nano-Actuators?

In order to control nanomachines via external signals, it will be necessary to use multiple actuators that can be activated independently.

Molecular structure is largely determined by where the electrons are. If the electrons can be made to move, the molecule may change shape. For some molecules, hitting them with light can make the electrons move. Thus, light-actuated molecular actuators have already been developed.

It would be nice if, instead of just "light," there was a whole palette of actuators, each activated by a different color. It would be nice if, instead of having to develop each one individually, a general approach could create a whole family of these actuators.

Nanotech solar cell research has explored ways that light energy can be transferred from one molecule to another - connect one molecule that absorbs the photon to another that creates electricity or hydrogen. So what if, instead of building an actuator molecule that both absorbs photons and moves, build one that doesn't absorb any photons - but can accept photon energy from a nanoparticle it's connected to?

It seems like this scheme would allow a variety of actuators to be built, sensitive to different frequencies of light, simply by swapping out the nanoparticles. Frequency-specific nanoparticles already exist, and the frequency can be tuned simply by adjusting the size of the nanoparticle when it's fabricated.

I'm not up to date on the relevant research, so this idea may already have been proposed elsewhere. And, of course, it may not work. But it seems plausible... and if it did work, it would provide a means of broadcast control of nanomachines, without needing physical macro/nano contact, and with multiple actuators individually controllable.

Chris Phoenix

Comments

[jim moore]

Chris,
In the nano-radio, a (charged) carbon nanotube directly turns frequency specific EM radiation (radio waves) into mechanical motion (vibration). This could be a general way to input information and power into nanosystems.

By changing the length and / or width of a sheet of graphene you change frequencies of light it absorbs, so there is an easy way to make a wide variety of frequency specific actuators.

The main unsolved problem is how to turn the vibration into useful work. Or perhaps a different design could get the carbon nanotube (or sheets of graphene) to rotate rather than vibrate.

What do you think of this idea: Charge one end of a carbon nanotube negative and the other end positive. In the center attach the "power" nanotube to a different nanotube perpendicular to the other and free to rotate. The electric and magnetic fields in light will push the positive and negative charges on the nanotube in opposite directions. For the right frequency of light you should be able to get constant rotation in the nano rotor.