71

2008, , 1-16

Chinese Physics Education2008, 9(1), 1-16

2010, , 69-76

Chinese Physics Education2010, 11(1), 69-76

98 10 30 99 02 10 99 02 24

20% Fraunhofer

Fresnel

0.016 cm

652.5 nm 9 cm

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DiffractionNear-field diffractionFar-field

diffraction

70

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stream of particles

Huygens 16291695 Grimaldi

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652.5 nm

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1

L=50cm = 652.5 nm

9

0.02 cm

0.016 cm

0 cm 0.8 cm 10

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0.8

cm 9 cm 11

L=9

cm 12

12 1

10%

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400 500 600 700 800 Wavelength (nm)

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2

0 0.04 0.08 0.12 0.16 0.2 0.24 0.28 0.32

(cm)

0.1cm0.008cm0.016cm0.2cm0.3cm0.02cm0.025cm

9

74

0.075 0.080 0.085 0.090 Position (cm)

Inte

nsity

(a.u

.)

0

20

10

30

Inte

nsity

(a.u

.)

80

40

00.00 0.005 0.010 0.015

Position (cm) 10 11

0.01 0.03 0.05 0.07 0.09 Position (cm)

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nsity

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0

10

20

30

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1L= 50 cm

L(cm) n d(cm) y(cm)(cm)

%

50 1 0.01 0.45 0.00009000 0.00009111 39.63%

50 2 0.01 0.9 0.00009000

50 3 0.01 1.4 0.00009333

2L= 90 cm

L(cm) n d(cm) y(cm)(cm)

%

90 1 0.01 0.85 0.00009444 0.00009167 40.48%

90 2 0.01 1.65 0.00009167

90 3 0.01 2.4 0.00008889

90 4 0.01 3.3 0.00009167

75

13

750

652.5 nm 0.016

cm 9 cm

9 cm

10%

20%

1.

vol. 11, No. 1,

pp9-14(2002)

2. 2002

185~186.

3. 1988

1-60

4. 2006

106-119

5. Ajoy Ghatak (2009). Optics. Mcgraw-Hill,

18.3-20.20.

6. David Halliday, Robert Resnick, Jeart Walker

(2001). Fundamentals of Physics. Wiley,

861-896.

7. Harris Benson 1995 University

Physics.Wiley, 761-786.

13. 40 10

76

Study of single-slit diffraction

Cheng-Nan Tsai Shun-Hsing Wang Cheng-Han Zhou Jian-Rong Wu Yao-Tsung Lin Cheng Shiu University

Abstract

The experiment of single-slit diffraction is one of the important physics experiment to

introduce the wave optics. Using eye-measurement of tradition method to record the bright and dark point of single-slit diffraction, the experimental results indicate that the wavelength error percentages are over 20%. This analysis is the far-field diffraction (Franhofer diffraction). Another diffraction is near-field diffraction (Fresnel diffraction) which can not be analyzed by eye-measurement method.

This research analyses the conditions of influenced the single-slit using the computerization. At first, we change the distance between slit and detector to find out the relation of non-diffraction, near-filed diffraction, and far-field diffraction. For the 0.016 cm-slit width, using He-Ne laser with 652-nm wavelength to pump, the critical distance is 9 cm. If the distance less than the critical distance indicates the near-field diffraction, otherwise, it indicates the far-filed diffraction. Computerization indicates that the wavelength error percentages are less than 10%. Second, we analyze the relations between slit width and the diffraction. For the 50 cm distance, the width of slit must less than 0.02 cm which can be clear to find out the far-field diffraction. Third, the color mixture or separate experiments are good for understanding consists of three primary color. The single-frequency light can successfully structure the far-field diffraction experiment.

Key words: diffractionnear-field diffractionfar-field diffraction