Lenses - RP Photonics

What are Lenses?

Physical Origin of Wavefront Changes

The Focal Length

Lensmaker's Equation

Conjugate Ratio

Thin and Thick Lenses

The Lens Equation

Focusing a Collimated Beam

Numerical Aperture and f Number of a Lens

Biconvex, Plano-convex, Biconcave, Plano-Concave and Meniscus Lenses

Centration of Lenses

Aberrations Caused by Lenses

Laser-induced Damage and Thermal Effects

Aspheric Lenses

Achromatic Lenses

Cylindrical and Astigmatic Lenses

Infrared Lenses

Multiple Element Lenses

Fabrication of Lenses

Coatings for Lens Surfaces

Lens Types According to Applications and Optical Functions

Standard Lenses versus Custom Lenses

Specialty Lenses

Frequently Asked Questions

What is an optical lens?

What is the focal length of a lens?

What is the difference between converging and diverging lenses?

What are optical aberrations?

How can chromatic aberrations be corrected?

What is an aspheric lens?

What is the difference between a spherical and a cylindrical lens?

What is the numerical aperture (NA) of a lens?

Summary:

An optical lens is a transparent component, typically made of optical glass or polymer, which uses curved surfaces or a varying refractive index to modify the wavefront curvature of light, causing it to focus or defocus. The primary characteristic of a lens is its focal length ($f$), and its focusing power can be calculated with the lensmaker's equation.

Lenses come in various shapes like biconvex, plano-convex, and meniscus, each suited for different applications. The article discusses key concepts such as the lens equation for imaging, the numerical aperture (NA) which limits resolution, and the f-number used in photography.

A major topic is optical aberrations, including spherical aberrations, which can be corrected with aspheric lenses, and chromatic aberrations, which are minimized with achromatic lenses like doublets. Other types covered are cylindrical lenses for astigmatic focusing and lenses for infrared optics.

The article also explains multi-element lenses (objectives), anti-reflection coatings, and the differences between thin and thick lenses, with applications ranging from simple laser beam focusing and collimation to complex imaging systems.

(This summary was generated with AI based on the article content and has been reviewed by the article’s author.)