Energy hn Photon Electron Frequency n “Size”? l = c/n momentum? wave: each particle responsible for the wave motion stays at the same average position, just inducing the motion of the next particle. (case of light wave in a dielectric) TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AAAAAAA

Nature of light, polarization Light wave: electric-magnetic field oscillating transverse to the propagation direction Medium? Quantized amplitude Zero-energy? Photon: no mass, but an angular momentum and a linear momentum

+ - E E Notion of the “ether”: a (fictitious?) medium to support the propagation of light waves. Today the“ether” has simply given way to vacuum, but it does not mean that the understanding of the nature of light has become simpler. + E E - The “neutral” gear is missing The minimum energy state of the quantum harmonic oscillator is not zero, but (1/2)hn.

Doppler Shift Wave propagating to the right

E l e m e n t a r y E n e r g i e s (e V ) An attosecond is to the second, as a second is to the age of the Universe (0:4 1018s). Atomic motion on molecular scale Nuclear motion in nuclei Electronic motion on atomic/molecular scales Words in speech zepto atto femto pico nano micro mili second 10-21 10-18 10-15 10-12 10-9 10-6 10-3 Time ( s ) Electrical network Gamma-ray X-ray Microwave Radio Infrared 50 Hz fm mm pm nm m m Mm km 10-15 10-12 10-9 10-6 10-3 103 6000 km W a v e l e n g t h ( m ) Pev Gev Mev keV eV meV meV neV peV 106 103 10-3 10-6 10-9 10-12 1012 109 E l e m e n t a r y E n e r g i e s (e V ) The higher the frequency, the higher the precision, stability, accuracy (?????)

The more confined the wave, the stronger its elementary energy

+ + + (d) - - - Tunneling Multi Photon -E -E -E t t t e e e High intensity! ?? MD? Chemist? NL optics? Filaments in air? Multiphoton ionization? Tunneling Tunneling Multi Photon -E -E -E (d) t t t - e + + + - e - e

Quarter wave to change from linear to circular POLARIZATION Changed by a wave plate Quarter wave to change from linear to circular Half wave plate to turn linear 90 degrees y y y x x x Linear polarization Quarter wave plate circular polarization

Photon momentum: SPIN ANGULAR MOMENTUM Of light Mechanical Kinetic Energy 5 pJ 20 kW Green beam Circularly polarized laser

Photon momentum: Kinetic energy ORBITAL ANGULAR MOMENTUM Linear momentum Kinetic energy

If there is a linear momentum of the photon, there is also an angular momentum A mechanical gyroscope is based on the conservation of angular momentum Best description of a laser gyro: DOPPLER SHIFT SEEN BY THE OBSERVER RW n(1 - ) c R W n(1 - ) RW c 4A n R W W Dn = 2RW = = Pl c l/2

If there is a linear momentum of the photon, there is also an angular momentum Comptes rendus de l’academie des sciences pp1410-1413 (1913) M2 F M1 M3 B M4 L

The Fiber Optic Gyroscope or FOG is nothing more than the Sagnac interferometer LASER D FIBER

Radiation pressure Mariana Trench: 1000 Bar Plasma physicist: accelerate an electron to mass increase of 50% (1018 W/cm2)

Representation of the field - notations

Constructive and destructive Waves of the same k vector, same frequency Superposition is just like adding two vectors , Constructive and destructive constructive destructive

Waves of the same k vector, same frequency Example of a laser: Constructive interference: adding two co-propagating beams of amplitude The intensity in each beam is Incoherent sum: the total intensity is I = 2I0 Coherent constructive sum: the total intensity is I = 4I0 Coherent destructive sum: the total intensity is I = 0 What happened to energy conservation???