While cameras and cutting-edge microscopes have come on leaps and bounds in recent years, the optical technology these kind of products use hasn't really changed since the mid-1700s. Even the highest spec gear relies on compound lenses, which were invented around 1730. Their main function is to bring together different wavelengths of light that otherwise focus in different spots. This corrects what's called "chromatic aberrations," or in other words, the purple halo that appears in images when the wavelengths are focused at different points. The problem is, these lenses are bulky, expensive and not as effective as they could be. But researchers at Harvard have found a solution with its newly-developed "metacorrector".