Optoelectronics is the study and application of electronic devices that interact with light, and thus is usually considered a sub-field of photonics. In this context, light often includes invisible forms of radiation such as gamma rays, X-rays, ultraviolet and infrared. Optoelectronic devices are electrical-to-optical or optical-to-electrical transducers, or instruments that use such devices in their operation.

Electro-optics is often erroneously used as a synonym, but is in fact a wider branch of physics that deals with all interactions between light and electric fields, whether or not they form part of an electronic device.

Optoelectronics is based on the quantum mechanical effects of light on semiconducting materials, sometimes in the presence of electric fields.

• Photoelectric or photovoltaic effect, used in:
  • photodiodes (including solar cells)
  • phototransistors
  • photomultipliers
  • integrated optical circuit (IOC) elements
• Photoconductivity, used in:
  • light-dependent resistors
  • photoconductive camera tubes
  • charge-coupled imaging devices
• Stimulated emission, used in:
  • lasers
  • injection laser diodes
• Lossev effect, or radiative recombination, used in:
  • light-emitting diodes or LED
• Photoemissivity, used in
  • photoemissive camera tube

Important applications of optoelectronics include:

• Optocoupler
• optical fiber communications