Wavelength

• Wavelength is defined as the difference between two successive crust or trough. It is denoted by λ.
• Wavelength is nothing but length of a full cycle of a wave from one point to the next same point.

Finding Wavelength

• Wavelength formula for any wave given by

• These are the wavelengths in electromagnetic spectrum.

Subwavelength

• A subwavelength-diameter optical fibre (SDF or SDOF) is an optical fibre whose diameter is less than the wavelength of the light being propagated through it.
• An SDF usually consists of long thick parts (same as conventional optical fibres) at both ends. A subwavelength-diameter fibre wraps light around human hair.

Angular wavelength

• A quantity related to the wavelength is the angular wavelength (also known as reduced wavelength), usually symbolized by ƛ (lambda-bar).
• It is equal to the "regular" wavelength "reduced" by a factor of 2π (ƛ = λ/2π).