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Sound Crystals
Description
You are looking at a silicon nitride membrane 1000 times thinner than a human hair. It is patterned with a phononic crystal, a regular arrangement of holes that shield the central region from sound waves. These devices enable experiments that test the quantum nature of all the objects around us.
Top left: optical image of a 50 nm thick silicon nitride membrane patterned with a phononic crystal. The defect region is about 250 microns wide. Top right: a similar membrane imaged through a polarizer, an analyzer and a Nomarski prism. Bottom left: optical image of a similar membrane coated with 50 Å of platinum. Bottom right: dark field optical image of a similar membrane which also has a photonic crystal patterned in the defect region to enhance the reflectivity for 1064 nm light.