Lecture 3

Question 1

wave equation?

Answer 1

-light is a wave and can be described using wave equation

A=Ao cos (kx-wt+phase shift)

(wave vector) k=2pi/lambda (wavelength)
(angular freq) w=2pi/T (period)

Question 2

what is the superposition principle?

Answer 2

waves will combine, overlapping eachother and propagating on top of each other:
constr int in phase bigger amplitude
destru int out of phase no signal

Question 3

what is huygens-fresnel principle?

Answer 3

shows us how light behaves as a wave.when light interacts with material at an interface, points of interaction will be sources for new circular waves which will then interact with eachother creating a wave front

Question 4

snells law?

Answer 4

fermats principle:light travels path of shortest time not distance
snells law:
n1sin1=n2sin2

Question 5

total internal equation?

Answer 5

Theta critical = sin **-1(n2/n1)
Total internal reflection usually takes place when light moves into a medium that is less dense than incident medium. No refraction takes place

Question 6

Brewster’s angle?

Answer 6

Occurs when angle between relflected and refracted rays is 90 degrees. Reflected ray is polarized and refracted ray is slightly polarized.
Brewster Angle= Tan**-1(n2/n1)

Question 7

Pinholes and irises?

Answer 7

mimic eye
pinhole effect: smaller the pupil size the less defocus from spherical aberrations are present
all unfocused rays are blocked leaving only focused light to land on retina to form clear image

Question 8

mirrors?

Answer 8

reflect light
broadband or narrowband
flat or curved
dielectric mirrors: light interferes with itself constr and/or destru.
metallic mirrors: silver and alum

Question 9

beam splitters?

Answer 9

optical device that splits beam of light into two

Question 10

filters?

Answer 10

control intensity of light and spectral characteristics. wavelengths can be filtered.

Question 11

prisms?

Answer 11

different colors of light travel at diff speeds inside the glass.bent and spread out as they leave

Question 12

gratings?

Answer 12

disperses light composed of lots of diff wavelengths (white light) into light components by wavelength. Angles of diffracted light components determined by wavelgnths

Question 13

polarizers

Answer 13

applied to transverse waves and specifies the geometrical orientation of oscillations.