cLaser-"Light Amplification by The First Ruby laser Stimulated Emission of Radiation NCoherent, high intensity light beams cElectron transitions are initiated by an external stimulus (as opposed to spontaneous emission) .g. Ruby laser(Ruby 05%Cr,O The ruby laser is the first type of aCr provides electrons states for single laser actually constructed, first demonstrated in 1960 by T.H. Maiman. It is the symbol of naIssance o of laser techniques. Lasers: Light Amplification by Typical Setup of a Laser Stimulated emission of radiation Optical lification Output coupling The light from a typical laser emerges in an extremely thin nost pendular Optical Pump process more photons at the same wavelength If the light is the htest bit off axis. it will be lost from the beam Shedding Some Light Shedding Some Light How the Laser Works How the laser works cont kashItu emit photons Partially Reflective Mirror Atoms become excited matic, single-phase, columnated The flash tube fires light at the ruby rod. The light excites the ruby through the half-silvered mi the atoms laser light4 Laser¾¾“Light Amplification by Stimulated Emission of Radiation” Coherent, high intensity light beams Electron transitions are initiated by an external stimulus (as opposed to spontaneous emission) e.g. Ruby laser (Ruby is 0.05%Cr2O3 in Al2O3 ) Cr provides electrons states for single wavelength emission The First Ruby Laser The ruby laser is the first type of laser actually constructed, first demonstrated in 1960 by T. H. Maiman. It is the symbol of naissance of laser techniques. Typical Setup of a Laser Pump process Optical feedback Optical feedback Output coupling Optical amplification (Optical gain) The light from a typical laser emerges in an extremely thin beam with very little divergence. The high degree of collimation arises from the fact that the cavity of the laser has very nearly parallel front and back mirrors which constrain the final laser beam to a path which is perpendicular to those mirrors. The back mirror is made almost perfectly reflecting while the front mirror is about 99% reflecting, letting out about 1% of the beam. This 1% is the output beam which you see. But the light has passed back and forth between the mirrors many times in order to gain intensity by the stimulated emission of more photons at the same wavelength. If the light is the slightest bit off axis, it will be lost from the beam. Lasers: Light Amplification by Stimulated Emission of Radiation Shedding Some Light How the Laser Works The flash tube fires light at the ruby rod. The light excites The laser in it’s non-lasing state the atoms. Flash Tube Partially Reflective Mirror Mirrored Surface Atoms become excited Emitted Light Some of these atoms emit photons. Shedding Some Light How the Laser Works Cont. Some of these photons run in a direction parallel to the ruby's axis, so they bounce back and forth off the mirrors. As they pass through the crystal, they stimulate emission in other atoms. Monochromatic, single-phase, columnated light leaves the ruby through the half-silvered mirror ¾ laser light!