Photonics: Computing At Light Speed
Brrring, Brrrring! The phone rings and it's your friend Raj, calling you from India, thousands of miles away. Have you ever wondered how your voices travel so fast on a telephone or how speedy e-mails travel from computer to computer? The high-speed secret lies in the fastest thing we have in the universe: light. The speed of light can be as fast as 186,000 miles per second. This means that in one second, light can travel about seven times around the Earth.
Many decades ago, scientists developed the use of light for telephone and Internet technologies, or optical communication. Within this field, scientists also study how to transmit, control, and detect particles of light called photons. This is the...
The Full Spectrum of Light
Light comes in a wide range of wavelengths—a term used to measure the length of the light wave from peak to peak. The wide range of light wavelengths is called the electromagnetic spectrum (a combination of electric and magnetic waves). Human eyes can only see a very small part of this range, called visible light. When you glimpse a rainbow, you're seeing a range of wavelengths in the visible light spectrum—the colors red through violet.Just beyond the visible light range is the infrared range. We can't see infrared light, but we can feel it through heat from sunlight, a fire, or a heat lamp. On the other side of visible light range is the ultra-violet range. Because ultra-violet light has a shorter wavelength and therefore more energy, we put on sunscreen to protect our skin from the damaging radiation of ultra-violet light.Image: Click here to view a larger version of the electromagnetic spectrum.