All electronic devices consist of billions of transistors, the key building block invented in Bell Labs in the late 1940s. Early transistors were as large as one centimeter, but now measure about 14 nanometers. There has also been a race to further shrink devices that control and guide light. Light can function as an ultra-fast communication channel, for example, between different sections of a computer chip, but it can also be used for ultra-sensitive sensors or novel on-chip nanoscale lasers.