1. Wavetrains and Coherency

2. © 2006 Walter Fendt Beats Animation http://www.walter-fendt.de/ph11e/beats.htm

3. y(x) = Sin x © SPK

4. y(x) = [Sin x + Sin (1.08 x)]/2 © SPK

5. y(x) = [Sin x + Sin(1.04 x) + Sin (1.08 x)]/3 © SPK 0 < x < 200

6. y(x) = [Sin x + Sin(1.02 x) + Sin (1.04 x) + Sin(1.06 x) + Sin (1.08 x)]/5 © SPK 0 < x < 400

7. y(x) = [Sin x + Sin(1.01 x) + Sin (1.02 x) + Sin(1.03 x) + Sin (1.04 x) + Sin (1.05 x) + Sin (1.06 x) + Sin (1.07 x) + Sin (1.08 x)]/9 © SPK 0 < x < 400

8. y(x) = [Sin x + Sin(1.01 x) + Sin (1.02 x) + Sin(1.03 x) + Sin (1.04 x) + Sin (1.05 x) + Sin (1.06 x) + Sin (1.07 x) + Sin (1.08 x)]/9 © SPK

9. Solitary pulse

10. For -L +L E0E0

11. Fourier integral

13. k p =2

14. Wave packet or Wave group for k p =k

15. Frequency Bandwidth Range of frequency k (or ) in wavetrain ( k) (or

17. Temporal coherence: Coherence time: Coherence length: © SPK

18. Spectral lines from helium gas tube

19. A characteristic Spectral line

20. Spectral line broadening 1.Natural linewidth 2.Doppler broadening 3.Collision broadening 4.Pressure broadening

21. Red Cadmium= 6438 Å = 10 10 Hz, 30 cm Yellow Sodium = 10 9 3 cm = 5893 Å He-Ne Laser 6328 Å 300 m = 10 6 Hz, © SPK

22. Kr discharge lamp has roughly the following intensity distribution at various wavlengths, (in nm), Estimate the coherence length of the Kr source.

23. Coherence time Coherence length