Lasers MOD 3

Geometrical Optics

A branch of optics that models light propagation using rays

rays

straight lines representing the
path of light

rectilinear propagation

light travels in straight lines in a uniform
medium

Geometrical Optics Key principles

rectilinear propagation reflection, and refraction

Light ray

represent the direction of energy flow in light
waves

Ray Tracing

A method used to determine the path of
light rays after they reflect from a mirror surface

Ray Tracing key reference
points

focal point and the center of curvature

Reflection on Curved Surfaces

Apply the law of reflection to determine the direction of reflected
rays.

Reflection On Plane Surfaces

angle of
incidence equals the angle of reflection,
and all involved rays lie in the same
plane

Total Internal Reflection

When light moves from a denser to a less dense
medium and strikes at an angle greater than the
critical angle, it is entirely reflected back into the
denser medium

Refraction

When light transitions between media of
different refractive indices, it bends according to
Snell’s law

Concave Mirrors images

Can form both real and virtual
images

Concave Mirrors beyond the focal point

produces a real, inverted image that can
be projected onto a screen

Concave mirror focal point

No image is formed

Concave Mirrors within focal point

a virtual, upright image
appears behind the mirror

Convex Mirrors

Always produce virtual, upright,
and reduced images that appear behind the mirror,
regardless of the object's position.

Plane Mirror Images

image distance equals the object distance, and the image is
upright and of the same size as the object

Plane Mirror

form images by reflecting light rays, creating virtual
images that appear behind the mirror

Magnification is determined by

ratio of the image height to the object height.

Positive
magnification indicates

upright image

negative magnification indicates

inverted image.

Specular reflection

smooth

Diffuse reflection

rough

Plane Mirror incident and reflected ray

Always equal

At each point on the curved surface one can draw

a surface tangent (a plane
surface).

REFRACTION Lower to higher:

refracted ray
bends toward the normal

REFRACTION Higher to lower:

refracted ray
bends away from the normal

CRITICAL ANGLE

The angle of incidence at which light, moving from a denser to a less dense medium,
refracts along the boundary, leading to total internal reflection if exceeded

Object and image distances p and q curved

Left of vertex

both positive

Object and image distances p and q curved

Right of vertex

both negative

Radius when center of curvature C is to the left

positive

Radius when center of curvature C is to the right

negative

Vertical dimensions above optical axis

are positive

Vertical dimensions below optical axis

are negative

focal length for concave mirrors

is positive

focal length for convex mirrors

is negative