Vladimir G. Niziev NATIONAL UNITED UNIVERSITY Miao-li, Taiwan Selected slides from course of lectures

Head of laboratory Institute on Laser and Information Technologies RUSSIAN ACADEMY OF SCIENCES Vladimir G. Niziev Citizen of RUSSIA

5 Making substitution E(r,,z,t) ~ E(r,,z) exp(-i t); H(r,,z,t) ~ H(r,,z) exp(-i t) ;k= /c Maxwell equations E and H are vectors.0 c 4 c 1,4,0 c 1 Hj,EH EHE If a wave propagates in free space external charges and currents are absent = 0, j = 0.00 c 1,0,0 c 1 H,EH EHE Wave equation E and H are vectors EE tc 1 HH tc 1 0HH 2 k.00 c 1,0,0 c 1 H,EH EHE 0EE 2 k0EE 2 k

6 TEM 00 TEM 10 TEM 20 TEM 11 TEM 21 TEM 01 TEM 02 TEM 12 Laguerre – Gauss transverse modes of stable resonators for round mirrors TEM p1 p = 0,1,2…

7 t Perfect temporal coherence t Wavefront Direction of wave propagation t t Bad (limited) temporal coherence Temporal coherence

8 Perfect temporal coherence Bad (limited) temporal coherence Time of coherence

9 E The main reason of bad (limited) temporal coherence Coherence

10 Discharge pulse duration ~ 1 s Laser pulse duration ~ 0.03 s Time Typical time of gas dynamic processes ~ 30 s Variable delay time Screen Partial mirror Total mirror Ruby laser Objective Interferometry Mach-Zehnder interferometer

11 Interferometry Sound speed ~ cm/s Time of formation of sound wave ~ 30 s Size of heated region is ~ 1cm

12 Lidar (detection of leakage in gas pipeline)

13 Lidar of differential absorption

n n tg = Brewster angle Fresnel law

15 Linear amplification Stationary state of inversion population. It is dynamic but not static Pumping Spontaneous emission or/and collisions Pumping

16 Atom-photon interaction Only resonance interaction is possible ! No excitation ! Excitation of atom Atom in the ground state Interaction with photons Excitation of atom

17 Nd:YAG laser Logarithmic scale Crystal Flash lamp or diode lasers pumping Main wavelength 1064 nm Output power Watts CW, pulse, pulse periodic

18 Damage of eyes by laser radiation The range of wavelength Direct hit of laser beam to eyes is very dangerous VISIBLEULRAVIOLETINFRAREDULRAVIOLETINFRAREDVISIBLE Safety first !

19 Computer model Military plane Drafts Plastic copy Laser stereo lithography

20 Laser stereo lithography Resolution is 10 m Micro models

21 Operation on heart Transmyocardial revascularization (scheme of procedure) Lasers for cardio surgery

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