Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Optics 4 > Optics Definitions > Flashcards

Optics Definitions Flashcards

1
Q

What is diffraction?

A

Change in direction of propagation of light NOT DUE TO REFLECTION OR REFRACTION

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the phenomenon of diffraction

A

Deviation from rectilinear propagation that occurs when light advances beyond an obstruction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

If rays travel in straight lines, what should the shadow pattern look like?

A

Should have sharp edges!

-diffraction blurs the edges

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is Huygens principle?

A

all points on a wavefront can be considered as point sources for the production of secondary wavelets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Fresnel expanded Huygens principle to say…

A

-the secondary wavelets undergo MUTUAL INTERFERENCE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

for single-slit diffraction, how must d and wavelength be in relation to the width of the slit (a)?

A
  • wavelegth must be greater than or equal to a

- d must be GREATER than a

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

the angular location for the first minimum does what as the slit width increases?

A

-gets smaller!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is fresnel diffraction?

A
  • near field

- source of light and the screen are at a finite distance from the diffraction aperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is fraunhofer diffraction?

A
  • far field

- source of light and the screen are at infinite distance from the diffraction aperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

which diffraction, fresnel or fraunhofer, results in collimated light?

A

-fraunhofer (far)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

which diffraction is easy to observe and calculate?

A

fraunhofer (far)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

which diffraction can vary due to distance changes between the slit and the screen?

A

fresnel (near)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is a poisson spot?

A

bright in the center of a shadow

-present in Fresnel diffraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is Rayleigh’s criterion?

A

-when the central maximum of one image falls on the first minimum of another image, the images are said to be JUST RESOLVED

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

snellens acuity is equal to…

A

the reciprocal of the minimum resolvable angular detail

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

If you already see 20/20 and look through a pinhole, what will happen to the VA?

A

-it will reduce to 20/30

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

according to ISO standard, what resolution efficiency is acceptable for product release?

A

greater than or equal to 60%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is apodization?

A

remove the rings around the central maximum and concentrate energy in the central maximum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what kind of filter eliminates diffraction pattern?

A

gaussian filter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is the stile crawford effect?

A

-light efficiency of of rays entering at the center of the pupil is greater than the rays entering through the edges

21
Q

diffraction grating consists of what?

A

-many slits with a very small slit separations

22
Q

what is blazed grating?

A

diffraction grating that is designed to channel light away from the central max into first or second order max

23
Q

what is the blazing angle?

A

angle at which efficiency is max

24
Q

diffraction grating efficiency reduces whith what?

A

reduces with higher wavelength

25
Q

how do you determine the nummber of seconday maxima of diffraction grating?

A

number of slits-2

26
Q

what is an Airy disk>

A
  • diffraction pattern
  • bright center
  • airy pattern are the rings
27
Q

what is a zone plate?

A

-optical device that blocks alternate zones

28
Q

what is a point image?

A

-formed when a diffraction grating creates inwardly bending spherical diffraction wave

29
Q

zone plates block the wave that cotributes to destructive pattern, making the image…

A

dimmer

30
Q

phase plates contribute to constructive interference, making the image…

A

-brighter

31
Q

what is a phase plate?

A

-diffraction waves contributing to destructive interference undergo a phase change to make them constructive

32
Q

what is a hybrid lens?

A

a single refractive lens with a phase plate imbedded on one side of its surface

33
Q

the zero order on a diffractive contact lens has what power?

A

-no power! if any, it is the base power for distance

34
Q

the first and other orders for a diffractive contact lenses has what power?

A

add power for near vision

35
Q

with diffractive lenses, what is the expected VA?

A

far: 20/20
near: 20/40

36
Q

what is dysphotopsia?

A

unwanted patterns onto the retina (blur the retinal image)

37
Q

what is positive dysphotopsia?

A

bright artifacts onto the retina (halos and glare)

38
Q

what is negative dysphotopsia?

A

blockage of light onto the retina (shadows and dark spot)

39
Q

fresnel’s lens increases the luminosiy of the lighthouse lamp by a factor of…

A

4

40
Q

how does iridescence in nature work biology? chemistry?

A

biology: absorption at certain wavelengths and reflects at others
Chemistry: interference, diffraction, scattering

41
Q

what is chitin?

A

-natral diffraction grating

42
Q

strength of iridescence depends on what?

A

groove density and surface quality

-high groove density and smooth surface means stronger interference

43
Q

unlike conventional imaging, holographic imaging…

A

light from each point on the object will reach all points on the film

44
Q

for holographic imaging, what kind of image is formed at m=1? m=-1? which one is usually viewed?

A

m=1: real image, not usually viewed

m=-1: virtual image, usually viewed

45
Q

in holographic imaging, when will you see a 3D image and when will you see a rainbow image?

A

horizontally viewed: 3D

Vertically viewed: rainbow

46
Q

for a perfect eye, a larger pupil means….

A

a smaller image

47
Q

for a typical eye, a larger pupil means….

A

a larger image

48
Q

what size pupil will give you the best retinal image?

A

3mm

Optics 4 (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions