STE 15091 Experiment Pack - Wave Optics

INTRODUCTION

This advanced Experiment Pack covers optics topics through to A level. It comes with an extremely helpful, fact filled 32 page Instructions and Teaching Guide to assist in setting up and teaching 12 wave optics experiments including interference, diffraction and polarisation using white light and monochromatic laser light. The optical bench and lenses can also be used for basic geometrical optics experiments.

TOPICS COVERED

1. Optical waves
2. Dioptrical projector
3. Diode laser
4. The speed of optical wave fronts
5. Polychromatic and monochromatic sources
6. Emission spectra
7. The diffraction of light
8. Diffraction through a hole
9. Diffraction through a slit
10. How to measure the wavelength
11. Light interference
12. Young’s interference experiment
13. How to measure the wavelength
14. The diffraction grating
15. Linear polarization
16. Polarised light
17. Polarisation through reflection
18. Brewster’s angle

EQUIPMENT

EXAMPLE EXPERIMENT

(all worksheets have necessary diagrams) 

14) The diffraction grating

It is possible to obtain more evident fringes than with Young’s apparatus by using diffraction gratings which are made of many parallel slits (figure 31).

The directions of the diffracted rays where intensity maximums are found, expressed by the angles α_k with respect to the grating’s normal, can be determined from the distance p between any two consecutive slits (the step of the grating) and the wavelength of  radiation:

P sin α_k = k λ              (k=0, 1, 2, …)

The wavelength can be derived when distance d from two consecutive intensity maxima(corresponding, for example, to k=0 and k=1) is measured, using the following relation (figure 32)

λ= P. d/D

where D is the distance from the grating to the screen.

Experiment 9

Equipment:

Step 1:

Set up the apparatus as shown in figure 33, paying attention to distances as indicated.

Step 2:

Switch on the laser. A central bright spot appears and, laterally and symmetrically, a sequence of diffraction spots with large gaps between them.

Step 3:

Measure the distance between the central spot (maximum of intensity) and the first lateral maximum and calculate wavelength λ. The value of   p = 1/80 mm.