# Interference pattern from a plano-concave lens

• Joans
In summary, the conversation discusses a set-up involving a HeNe laser and a plano-concave lens, where interference between the two reflections on the lens can be observed on a reflection screen. The person is trying to determine the radius of curvature (RoC) from the observed pattern and notes that the pattern is sensitive to the orientation and position of the lens. The other person explains that the lens used is a three-dimensional spherical lens and the central dark spot is the point of tangency between the lens and the plane, with the other points forming the dark rings. They apologize for the delay in responding.
Joans
Hello. I need some sort of explanation. I was unsuccessfully trying to find information on the web and derivation by hand seems rather complicated for me. So I have a such set-up:

HeNe laser ->> plano-concave lense )], light is incident by some angle (NON 0°). then looking to reflection screen I clearly see two reflections and one of them (smaller) having clear Newton's rings pattern. As I understand it is interference between the first surface (concave) and the second surface (plane) reflections. My question is: can I somehow determine RoC from this pattern (attached)?

The pattern seems to be sensitive to orientation and position of the lens.

#### Attachments

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i had the problem for some time too
the key is to realize that the lens is not just two dimensional circle if that was the case what you said about forming straight line interference would be true but the lens used in the Newton ring experiment is a three dimensional spherical lens so you can imagine the central dark spot as being the point of the sphere that is tangent to the plane and the all the other points which are of the same height from the plane as forming those dark rings hope this helps sorry for the very very late reply

## What is an interference pattern?

An interference pattern is a phenomenon that occurs when two or more waves interact with each other. This results in the waves either reinforcing or canceling each other out, creating a pattern of alternating bright and dark spots.

## How does a plano-concave lens create an interference pattern?

A plano-concave lens is a type of lens that has one flat side and one concave side. When light passes through this lens, it causes the light waves to diffract, or bend, resulting in an interference pattern being created.

## What factors can affect the interference pattern from a plano-concave lens?

The interference pattern from a plano-concave lens can be affected by various factors such as the wavelength of the light, the curvature of the lens, the distance between the lens and the light source, and the angle at which the light enters the lens.

## How can the interference pattern from a plano-concave lens be used in scientific research?

The interference pattern from a plano-concave lens can be used in various scientific research, such as in the study of optics, diffraction, and wave interference. It can also be used in the development of technologies such as holography and interferometry.

## Are there any practical applications for the interference pattern from a plano-concave lens?

Yes, there are several practical applications for the interference pattern from a plano-concave lens. For example, it is used in the manufacturing of diffraction gratings, which are used in spectroscopy and laser technology. It is also used in the production of lenses for cameras and telescopes.

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