Remote controls work through sending electro magnetic waves through the air that the TV can pick up. The control sends out infrared waves which is a type of electromagnetic radiation, which includes radio, gamma, and micro waves, as well as all visible light.

We can not see the infrared light, as its frequency is a little too low for humans to detect, however it is sent out using a Light Emitting Diode, (or LED) that works in the same way an LED TV screen sends out light. These infrared waves are sent spherically in all directions, and a sensor in front of the TV picks up the wave traveling at light speed.

The remote does not just send a single infrared wave. In a way similar to morse code, the TV remote sends out a burst of multiple energy waves. The TV detector picks up these waves in succession, and based on the configuration, performs the desired task.

The remote emits a radio signal, and the receiver contains a radio receiver. In more modern systems, I think that the signal might be a laser instead of an ordinary flash. Basically it works the same way that a radio does.

Most television remotes use IR (infrared) waves to send signals. These waves behave just like visible light, except that humans can't see them. This is because they have a different, longer wavelength than visible light.

Using our knowledge of this wavelength, we can still make electronic sensors to detect infrared light. There are quite a few ways to do this, and they usually involve a special material that behaves differently when hit by infrared light. These sensors, or photodetectors, are in the receivers that pick up television remote signals.