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

WHERE CAN YOU FIND LASERS?

DIRECTIONAL MONOCHROMATIC COHERENT

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

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

COHERENT Light is a wave Coherent waves are completely in phase

DIRECTIONAL MONOCHROMATIC COHERENT Make you look cool

INTERFERENCE

DEMO: INTERFEROMETER

LIGO PRL 116, 061102 (2016)

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

STIMULATED EMISSION Source

NIF https://www.youtube.com/watch?v=yixhyPN0r3g

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

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

MOLECULAR MOVIE PRL 114, 255501 (2015)

MOLECULAR MOVIE https://www.youtube.com/watch?v=HhmBKd-_sRM LCLS pulse: 40fs – 300fs https://www.youtube.com/watch?v=HhmBKd-_sRM PRL 114, 255501 (2015) More details on scattering

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

DEMO: DIFFRACTION