Feed-back by the cavityMirrorMirror1E
Ei Ef Mirror Mirror Feed-back by the cavity
After several round trips...MirrorMirrorS1>SS1>S1>S>1>1>12S>>1E,Laser beamPhotons with:- same energy : Monochromatic- same direction of propagation : Spatial coherence- all in synchrony: Temporal coherence
Ei Ef Mirror Mirror Laser beam After several round trips. Photons with: - same energy : Monochromatic - same direction of propagation : Spatial coherence - all in synchrony: Temporal coherence
EnergyinputbypumpingTotalPartialreflectorreflectorOutputAmplifying mediumbeamLasercavityBroadRapidnon-radiativeFlevelstransitionsMetastablelevelsPumping lightLasertransition(694.3nm)GroundstateEnergylevelsofchromiumionsinruby
TherubylaserRuby is corundum ( one form of Al,O3 ) with 0.04~0.5%Cr3+ ion as an impurity replacing aluminium ions. Thealuminium ions, and hence the chromium ions, occupydistorted octahedral sites.When light is absorbed, one of these electrons can undergoa transition to a higher energy 3d level. The chromium ioncould now simply emit radiation of the same wavelengthand return to the ground state
The ruby laser Ruby is corundum ( one form of Al2O3 ) with 0.04~0.5% Cr3+ ion as an impurity replacing aluminium ions. The aluminium ions, and hence the chromium ions, occupy distorted octahedral sites. When light is absorbed, one of these electrons can undergo a transition to a higher energy 3d level. The chromium ion could now simply emit radiation of the same wavelength and return to the ground state
The interaction of light with atomsTi3+ is an ion with one d electron outside a closed shell. Inthe free ion the five 3d orbitals all have the same energy.(3d,2-y2, 3d2)egEA3d12(3dxy,3dyz,3dxz)3doninIon in sphericalFreeionoctahedralcrystal sitesite
The interaction of light with atoms Ti3+ is an ion with one d electron outside a closed shell. In the free ion the five 3d orbitals all have the same energy