Lasers usually conjure up the image of bulky devices with mirrors inside that shine a coherent beam out one end. However, scientists from Kent University have created a model that's just a flat piece of stretchy LCE (liquid crystal elastomer) film. That material is like a rubberized version of the liquid crystals used in displays and is often used to make artificial muscles. When hit with a simple laser light source, the film produces a new laser beam that changes frequency when force is applied. That alone is cool (to laser people), but the new material may also result in a new class of sensors that can measure forces with extreme accuracy and relay the results over fiber optic cables.
Scientists created a specially tunable piece of glass-encased LCE material to "bounce" laser light internally, in much the same way that mirrors do in a regular laser. When factors like strain and temperature changes are introduced, the frequency of the LCE laser can be tuned between 370 to 705 nanometers, spanning most of the visible light range. That makes it useful as a fine-tuned laser, but could also result in a new class of sensors.
"In principle, it could be put into a shoe, to measure shear stress on a diabetic foot, and it could be interrogated by an optic fiber; a pulse of light could be sent in the fiber, and the color of the returning light from the laser emission would carry information about the strain," said Kent research lead Dr. Peter Plaffy-Muhoray. It could also be used to measure stresses and strains on remote objects using networks of optical cables -- giving engineers a new way to detect abnormal forces on critical infrastructure, for instance.