## Spontaneous Emission and Stimulated Emission

When light of suitable frequency incident on the substance, the atom of the substance go to the excited states by absorbing this light. The atom in the excited state come …

## What is Temporal Coherence

Coherence is the term used to describe the phase correlation phenomenon between two waves with respect to time or space. Temporal Coherence Temporal coherence is the correlation between the electric …

## 3 main Components of Laser

The term Laser is an acronym for Light Amplification by Stimulated Emission of Radiation. There are main 3 components of Laser device: The active Medium or laser gain medium. A …

## Properties of Photon

Before study the properties of photon we must have to know some basic introduction of photon. In 1905, Einstein explained photoelectric effect by considering light consisted of quantum of energy …

## Methods of Reducing Spherical Aberration

How to Reduce Spherical Aberration The following 5 methods are usually used to reduce the spherical aberration. By Stop Method. By using plano-convex lenses. By using two convergent lenses separated …

## Aberration in Optics and Types of Aberration

Aberration in Optics In the simple theory of image formation by lenses, it is assumed that an object is situated very close to the principal axis and each point object …

## Combination of Lenses

Suppose we have two lenses of focal lengths f1 and f2 separated by a distance x as shown in fig below. L1, L2 correspond to the position of two lenses …

## Translation Matrix

The matrix Tm is called Translation Matrix. The matrices can be used to find the position of the final image. The method of writing linear equations for the coordinates of …

## Fermat’s Principle of Least Time

What is fermat’s principle? This principle states that the light always travels that path in a medium from one point to another point which takes the minimum (i.e least) time. …

## Optical Path and Geometrical Path

The branch of physics which deals with the study of optical phenomenon like reflection, refraction, dispersion, interference, diffraction, polarization etc. is known as optics. Optics is classified into two categories: …