Lesson 2: Theoretical Optics Terminologies

Unit of wavelength: 1 billionth of a meter

Nanometer

Number of full wavelengths passing a point per second

Frequency

Spatial distance for one complete wave cycle: crest or crest or trough to trough

Wavelength

Maximum displacement or distance a wave particle moves from its resting point: wave intensity

Amplitude

How fast the wave disturbance travels through the medium

Speed

The time it takes for one complete wave cycle to pass a given point: inverse of frequency

Period

Highest point or peak

Crest

Lowest point or valley

Trough

Fundamental waves phenomena that bouncing off surfaces

Reflection

Fundamental waves phenomena that bending as they pass through different mediums

Refraction

Fundamental waves phenomena that bending around obstacles or through openings

Diffraction

Fundamental waves phenomena that waves combining to either amplify or cancel each outher out

Interference

The transvers, non-mechanical waves composed of oscillating electric and magnetic fields perpendicular to each other and the direction of propagation

Electromagnetic Waves

The properties of electromagnetic waves are:

1. Velocity

2. Amplitude

3. Frequency

4. Phase Angle

5. Direction of propagation

It travels in a straight line and can spread, scatter, and bend when they reach an obstacle, causing to either of this (diffraction, reflection, refraction)

Light

A substance where light travels

Medium

A smallest unit of light, it shows direction of propagation

Ray

Speed of light in vacuum

299,792,458km/s, 186,000 miles

It is the group of rays

Pencil of light

It is the group of pencils of light

Beam of light

A phenomenon where white light splits into its constituent colors (a spectrum, a rainbow) as it passes through a medium because different color bend or refract at different angles. It occurs because the refractive index of the material changes for each color

Dispersion of light

A law when light passes between different media, the angle of incidence and angle of refraction equals the respective refractive indices

Law of refraction

An optical flaw where a lens fails to focus all wavelengths of light onto a single point. The color fringing or purple fringing. It is caused by light dispersing through glass, it produces color fringes, commonly red/blue

Chromatic Aberration

Type of CA where the colors focus at different distances from the lens (axial), causing colored blurring in front of or behind

Longitudinal Chromatic Aberration

Type of CA where the colors focus at different positions on the image plane (lateral) resulting in color shifting, often at the corners of the frame

Lateral Chromatic Aberration

A converging lenses. It is thicker in the middle (positive focal length). It bends parallel light rays inward causing them to converge at a single point. e.g. (magnifying glasses, camera lenses, projectors, microscopes, and telescope) Used to correct hyperopic

Convex Lens

Image formation in convex lens where the object is outside the focal point

Real and inverted

Image formation in convex lens where the object is placed inside the focal point

Virtual and upright

A diverging lenses. It is thinner in the middle (negative focal length). It bends the parallel light rays outward or diverge them. The rays appear to originate from a virtual focal point on the same side as the object. Always produce virtual and upright. e.g. (peepholes, flashlight). Used to correct myopic

Concave Lens

CX-CC Optical lens that thicker in the center, converges light and steeper the CX side: designed to minimized spherical aberration. It is widely used to improve image quality in cameras, microscopes, and telescopes.

Positive Meniscus Lens

CX-CC Optical lens that is thinner at the center. It increases the divergence of the beam without introducing any significant spherical aberration when used in combination with another lens

Negative Meniscus Lens

Optical lens that the curvature in only one direction; transform a point source of light into a line image

Cylindrical lenses

Optical lens that use a series of concentric rings to reduce material thickness while acting as a large-aperture lens (lighthouse and spot lamps)

Fresnel lenses

Optical lens that is non-spherical surfaces that correct for spherical aberration to provide sharper, more accurate focus

Aspherical lenses

What is this type of lens?

Biconvex

What is this type of lens?

Plano-convex

What is this type of lens?

Positive-meniscus

What is this type of lens?

Negative-meniscus

What is this type of lens?

Plano-concave

What is this type of lens?

Biconcave