Light and Optics Concepts

Vocabulary flashcards covering key concepts in light and optics for exam preparation.

Specular Reflection

Occurs when light bounces off a smooth surface, resulting in a reflected ray at an angle equal to the angle of incidence.

Diffuse Reflection

Occurs when light bounces off a rough surface, scattering the light in many directions.

Snell's Law

States that n₁sinθ₁ = n₂sinθ₂, describing how light bends when passing from one medium to another with a different refractive index.

Total Internal Reflection (TIR)

Occurs when light traveling from a denser medium to a less dense medium strikes the interface at an angle greater than the critical angle, reflecting all light back.

Central Maximum

The brightest region in a diffraction pattern, located at the center, where constructive interference occurs.

Coherent Light Sources

Produce light waves with a consistent phase relationship, wavelength, and direction (e.g., lasers).

Incoherent Light Sources

Produce light waves with random phases, a range of wavelengths, and propagate in multiple directions (e.g., incandescent light bulbs).

Laser (Light Amplification by Stimulated Emission of Radiation)

Based on stimulated emission, where an incoming photon triggers an excited atom to emit a second photon with the same characteristics.

Beer-Lambert Law

States that absorbance is directly proportional to concentration, path length, and molar absorptivity, significant in quantifying light absorption.

Rayleigh Criterion

States two point sources are just resolvable when the center of one diffraction pattern coincides with the first minimum of the other.

Fluorescence

Emission of light by a substance that has absorbed light of a shorter wavelength, stops almost immediately when excitation source is removed.

Phosphorescence

Similar to fluorescence, but involves a delayed emission due to a transition through a forbidden spin state (triplet state).

Dichroic Filter

An optical filter that selectively reflects or transmits light based on wavelength, used to direct light in optical systems.

Numerical Aperture (NA)

A dimensionless number characterizing the range of angles over which an objective lens can accept or emit light.

Refractive Index

A measure of how much the speed of light is reduced inside a medium compared to its speed in a vacuum.

Resolution Limit

The smallest distance between two objects that can be distinguished as separate entities by an optical instrument.

Stimulated Emission

The process by which an incoming photon interacts with an excited atom, causing it to emit a photon with identical characteristics.