1. SPLASH FALL 2016 2016-12-04 ALEXANDRE GAUTHIER
LASERS
SPLASH FALL 2016
ALEXANDRE GAUTHIER

2. WHERE CAN YOU FIND LASERS?

4. DIRECTIONAL
MONOCHROMATIC
COHERENT

5. DIRECTIONAL Laser light propagates in beams
Gives you lots of power in a small area

6. MONOCHROMATIC White light is made up of many colors
Laser light is all one color / energy
Allows for well-controlled science experiments

7. COHERENT
Light is a wave
Coherent waves are completely in phase

8. DIRECTIONAL
MONOCHROMATIC
COHERENT
Make you look cool

9. INTERFERENCE

10. DEMO: INTERFEROMETER

11. LIGO
PRL 116, (2016)

12. BUILDING A LASER
1. Pump
2. Lasing Medium
3. Optical Cavity
Simulation

13. STIMULATED EMISSION
Source

14. NIF

15. ULTRAFAST LASERS Pulsed laser: ~10s of fs, ~100s of kHz
10 fs -> light travels 3 um
High peak power; more dangerous

16. ULTRAFAST LASERS
Camera has to integrate, electronics ~ ns timescale at best
Camera only sees signal for duration of light pulse
Can resolve femtosecond dynamics

17. MOLECULAR MOVIE
PRL 114, (2015)

18. MOLECULAR MOVIE https://www.youtube.com/watch?v=HhmBKd-_sRM
LCLS pulse: 40fs – 300fs
PRL 114, (2015)
More details on scattering

19. LASER CLASSES Class 1 – Always safe
Class 2 – Safe if you blink (visible light only)
Class 3 – Scattered light safe; beam can injure you
Class 4 – Scattered light dangerous
Also 1M, 2M, 3R

21. DEMO: DIFFRACTION