Classification of Optical Materials

CLASSIFICATION OF OPTICAL MATERIALS

Optical materials can be classified into three categories, based on their interaction with visible light, viz.

1. Transparent materials

2. Translucent materials

3. Opaque materials

1. Transparent materials

Materials that are capable of transmitting almost all light, with very little absorption and reflection are called transparent materials. Therefore using these material we can see the objects clearly.

Examples

Plain glass, clear water, etc

2. Translucent materials

Materials that allow only certain amount of light to pass through it and absorbs rest of the light are called translucent materials. Therefore, using these materials we can see the object diffusely (or) not clearly.

Examples

Butter paper, plastic covers, trace paper, frosted glass, hydrogel and colloidal materials.

Smoke, fog and clouds can also be considered as translucent materials.

3. Opaque materials

Materials which doesnot allow any light to pass through it and absorbs (or) reflect almost all the light are called opaque materials. Thus, we can't see the objects through these materials.

Examples

Metal is the best example, other materials such as wood, brick, stone, etc are also good examples for opaque materials.

Note: Metals when exposed to high frequency X-rays (or) y-rays, are considered to be transparent