What is a zone plate discuss its theory compare its action with that of a convex lens?

It is a transparent plate on which circles whose radii, proportional to the square roots of natural numbers 1, 2, 3… are drawn. The alternate annular zones thus formed are blocked. Such a plate behaves like a convex lens and produces an image of a source of light on the screen placed at a suitable distance.

What is a zone plate and how is it made derive an expression for its focal length?

The focal length of a zone plate is given by the relation f = rn2/n٨, Focal length of a zone plate is the distance measured along its axis at which the maximum is produced when the source of light is located at infinity i. e., when a plane wave front is incident on the zone plate.

Does zone plate behave like?

lens
zones, behaves like a lens which is simultaneously both converging and diverging. Improvements in the performance of such zone plates has recently led to some attention being given to their potential use as lenses in certain applications. of the zone plats and a hologram may be considered as a generalized zone plate.

What is the focal length of zone plate?

Fresnel zone plates

What is half period zone plate?

The distance between wavefront and point P is OP = b. point O is called the ‘pole’ of the wavefront corresponding to P. To find resultant intensity at point P due to wavefront, we divide the wavefront into a concentric half period zone. These period zone are known as fresnel’s half period zone.

What are the positive and negative zone plates?

(2) Positive zone plate : When odd zones are kept transparent to the light and even zones are made opaque, then it is called positive zone plate. (3) Negative zone plate : when even zones are kept transparent to light and odd zones are made opaque, then it is called negative zone plate.

What is positive zone plate?

(2) Positive zone plate : When odd zones are kept transparent to the light and even zones are made opaque, then it is called positive zone plate.

What is Zone Plate justify the name of Fresnel half period zones?

According to Fresnel’s the entire wave front can be divided into a large number of parts of zones which are known as Fresnel’s half period zones (HPZ’s). The resultant effect at any point on screen is due to the combined effect of all the secondary waves from the various zones.

Why are half period zones called so?

It is called half period because light reaching to observation point from each of that zone has period of π which is half of full period i.e 2π so called half period zone plate.. in case of zone plate we use black paint to cover alternative zones so that period became 2π so called zone plate or full period.

What is a zone plate justify the name of Fresnel’s half period zones?

What is the difference between positive and negative zone plate?

What is area of half period zone?

According to a very famous scientist named Fresnel, the entire area of wavefront can be divided into be ‘n’ number of smaller regions of zones and these zones are referred to as half period zones. Formula for area of Half Period Zone: π { pλ+λ2(2n-1)/4} = πpλ

What is a zone plate used for?

A zone plate is a diffractive optic that consists of several radially symmetric rings called zones. Zones alternate between opaque and transparent, and are spaced so that light transmitted by the transparent zones constructively interferes at the desired focus. One common use of a zone plate is to bring light from a distant source to focus.

What is zone plate theory in Fresnel?

Fresnel zone plate theory and equations. Learn about zone locations, resolution, bandwidth restrictions, and field of view. A zone plate is a diffractive optic that consists of several radially symmetric rings called zones.

What is the focusing ability of zone plates?

The zone plate’s focusing ability is an extension of the Arago spot phenomenon caused by diffraction from an opaque disc. A zone plate consists of a set of concentric rings, known as Fresnel zones, which alternate between being opaque and transparent. Light hitting the zone plate will diffract around the opaque zones.

What is plate tectonics theory?

Plate tectonics is a scientific theory that explains how major landforms are created as a result of Earth’s subterranean movements. The theory, which solidified in the 1960s, transformed the earth sciences by explaining many phenomena, including mountain building events, volcanoes, and earthquakes.