An Atomic Force Microscope (AFM) consists of a nanometer sized needle that is very close to the surface of a sample (without touching). The needle is close enough that it feels the electrostatic force of the sample. As the needle moves along over the surface (without touching), it "sees" the bumps on the surface by feeling a force and moving up and down. The movement is captured using a laser and a detector, and a high resolution image of the surface profile is created.
Photonic crystals are materials with a periodic dielectric pattern such that light of a particular frequency is forbidden to travel through the material. By introducing a defect into the material, the forbidden frequency can only travel along this defect in the material, essentially creating a loss-less waveguide. It is possible to build a resonator out of these materials where light of the particular frequency is effectively trapped.
Scientists have now used the AFM (which feels forces) on these Photonic Crystals resonators with light in them to "map" the light in the material. They also found they could change properties of the light in the material with the AFM tip. Really a very interesting article.
Here is the story.
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Oh what became of the Likely Lads? What became of the dreams we had? Oh what became of forever? Oh what became of forever? We'll never know! - The Libertines
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Using a Photonic Crystal and AFM to Map Light
