Optical technology is about the manipulation of light. It is about devices and mechanisms to change the direction of light, to store light, to slow light. The branch of physics that deals with investigating these phenomena is generally called optics.
Although nature is able to evolve optical devices such as lenses, optical technology is more about the devices and tools that humans have created to manipulate light.
A newton telescope that uses a curved mirror to collect and focus light. image: wikipedia
Examples include:
- Lenses, such as microscopes and telescopes
- Mirrors, prisms, diffraction gratings.
- Cameras (these are composite devices)
Visual technologies are about how light can get to our eyes using technology. Visual technologies can be combined with audio technology to produce TV or film projections. This is usually called Audio Visual technology.
The creation of light is a type of energy technology.