Diffraciton Grating Flashcards

1
Q

When the central maxima of one image falls on the first minimum of another image, the images are said to be just resolved. This limiting condition of resolution is known as

A

Rayleigh’s Criterion

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2
Q

Rayleigh’s criterion equation?

A

Theta=1.22 lambda/d

Smallest resolvable angle
Limiting angle of resolution

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3
Q

Snellen acuity is equal to the what?

A

Reciprocal of the minimum resolvable angular detail, expressed in minutes

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4
Q

How do you convert angles to minutes

A

X 180, divide by pi

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5
Q

According to ISO standard, R. E. > ________ is an acceptable image quality standard for industry product release

A

60%

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6
Q

To remove the rings around the central maxima and concentrate energy in the central maxima is called __________

A

Apodization

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7
Q

At the center of the anodized circular pupil, the intensity transmission is ______

A

100%

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8
Q

Diffraction pattern and apodization

A

For a clear circular pattern, airy’s disk contains 84% of the intensity in the diffraction pattern

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9
Q

Gaussian filter

A

86% of the intensity is inside the circle

-there are no rings, only smooth illumination fall off

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10
Q

What kind of filters do pupils act like?

A

Gaussian filters (apodized)

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11
Q

What is the stile crawford effect?

A

The luminous efficiency of rays entering at the center of the eye pupil is greater than the luminous efficiency of the rays entering through the edge of the pupil

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12
Q

Despite its retinal origins, the stiles crawford effect is sometimes modeled optically as a filter placed in front of the eye, in which the density of the filter increases from the center toward the edge of the filter, this is known as _________

A

Apodization

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13
Q

What influences the VA and visual performance of the human eye?

A

Stiles crawford apodization

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14
Q

Distance between maxima and 1st order minima is ________. This number also tells us how many maxima there are as well

A

D-2

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15
Q

A _____________ consists of many slits with a very small slit separation

A

Diffraction grating

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16
Q

Efficiency drops with ___________ number of slits

A

Higher

17
Q

Transmission grating

A
  • acts a laser beam splitter
  • less sensitive to polarization
  • less sensitive to alignment
  • efficiency reduces with higher wavelength
18
Q

CDs are an example of what?

A

Reflection diffraction grating

19
Q

A diffraction grating that is designed to channel light away from the central maximum (oth order) into 1st or 2nd order maximums

A

Blazed grating

20
Q

Angle at which the efficiency is maximum

A

Blazing angle

21
Q

Optical device that blocks alternate zones

A

Zone plate

22
Q

Diffraction image grating creates inwardly bending spherical diffracted wave

A

Point image

23
Q

Central order (0th) goes though

A

Straight

24
Q

1st order posting image is at

A

F2

25
Q

2nd order point image is at

A

F2/2

26
Q

3rd order point image is at

A

F2/3

27
Q

Fresnel zone plate blocks wave that contribute to destructive interference at the diffraction max, making the image formation much _______

A

Dimmer