Geometrical optics is also known as ray optics considers the light as a collection of rays in which the light is supposed to travel in a straight line, where the path in which the light travels is decided by the laws of refraction and reflection at interfaces between two different mediums. The discovery of these laws happened way back in 984AD and from then till now these laws are still used to design optical components and instruments. These laws can be written as:
When a ray of light strikes the interface line/boundary line between two transparent materials, it gets divided into refracted and reflected rays.
- • The law of reflection states that the angle of reflection is always equal to the angle of incidence and the reflected ray lies in the plane of incidence.
- • The law of refraction states that the sine of the angle of incidence divided by the sine of the angle of reflection is always constant, and the reflected ray lies in the plane of incidence.
where n shows the constant for any two materials and a given color of light. If the first material is air or vacuum, then the denominator becomes 1 and the n becomes the refractive index of the second material.
Fermat’s principle can also be used to derive the laws of refraction and reflection which states that the path taken between 2 points by a ray of light is the path that can be traveled in the least amount of time. Nowadays, precision lenses and precision optics are manufactured by keeping in mind that they have to serve for a specific purpose. Custom optical prism manufacturer are hired to manufacture these precision lens and optics.
Paraxial Approximations or Small-angle approximations are often used in order to simplify the geometric optics. By considering approximations, the mathematical behavior becomes linear which helps us to describe optical systems and components in simple matrices. This resulted in the techniques of paraxial ray tracing and gaussian optics, which are used to find the optical system's basic properties, such as object position and approximate image and magnifications.
The lens can be simply defined as a device that is used to produce converging or diverging rays of light with the help of refraction. The focal length of the lens is adjusted to make it a converging lens or diverging: the diverging lens has a negative focal length and a converging lens has a positive focal length. The smaller the focal length of the lens will be, the more the converging or diverging effect of the lens will be. Lensmaker’s equation is used to calculate the focal length of a simple lens.
Description: Geometrical optics and its characteristics and use of precision lenses and optics