Photonic Crystal

Why in news?

• A soft tunable photonic crystal with enhanced thermal stability and optical purity developed by researchers that reflects vivid colours in the visible spectrum has potential applications in making more durable and better reflective displays and laser devices.

About Photonic Crystals:

• Photonic crystals are optical nanostructures in which the refractive index changes periodically.
  • Refractive index, also called index of refraction is the measure of the bending of a ray of light when passing from one medium into another.
• This affects the propagation of light in the same way that the structure of natural crystals gives rise to X-ray diffraction and that the atomic lattices (crystal structure) of semiconductors affect their conductivity of electrons.
• Photonic crystals occur in nature in the form of structural coloration and animal reflectors.
• Examples found in nature include
  • Opal, butterfly wings, peacock feathers, etc., exhibiting distinct iridescent colours.

Applications of photonic crystals:

• Photonic crystals can, in principle, find uses wherever light must be manipulated.
• For example, dielectric mirrors are one-dimensional photonic crystals which can produce ultra-high reflectivity mirrors at a specified wavelength.
• Two-dimensional photonic crystals called photonic-crystal fibers are used for fiber-optic communication, among other applications.
• Three-dimensional crystals may one day be used in optical computers, and could lead to more efficient photovoltaic cells.

PRACTICE QUESTION:

With reference to ‘photonic crystals’, consider the following statements:

1. They doesn’t occur in nature

2. They are used for fiber-optic communication

Which of the statements given above is/are correct?

(a) 1 only

(b) 2 only

(c) Both 1 and 2

(d) Neither 1 nor 2

Answer