Tunable Dye Laser Scheme The dye is a large molecule with strong electronic absorption and many closely spaced internal (vibrational) states – essentially a continuum of internal states Tunable Dye Laser Scheme The pump pulse populates resonant internal states of the excited electronic singlet states S1 and also possibly S2. S2 Fast internal conversion occurs down to the lowest state of S1 (radiationless transitions in which energy is dissipated thermally) T2 This state lases down to an excited internal state of the ground electronic state So. S1 Fast internal conversion occurs down to the ground state of So so maintaining population inversion. T1 Care needs to be taken maintain population inversion by ensuring internal conversion to the triplet state T1 does not deplete S1 to quickly So

High power fixed-frequency laser beam is split and focused by cylindrical lenses to pump both the dye laser cell (~40%) and an amplifier cell (~60%) Pump Laser Stimulated emission occurs in the volume at the focus Cylindrical lense The grating is rotated gradually to tune the resonant cavity and so scan across the required frequency range Second dye cell –amplifies the output Beam splitter Cylindrical lense Dye Cell Output coupler Beam expanding telescope and grating

Rhodamine 6G

Tuning ranges of various laser dyes Stilbene 3 C102 Argon C102 Krypton C30 C8 Rn 110 R6G Kilon Red DCM Pyridine 2 LD700 400 450 500 550 600 650 700 750 800 Tuning ranges of various laser dyes

http://www.fineartradiography.com/hobbies/lasers/dye/

http://en.wikipedia.org/wiki/File:Coherent_899_dye_laser.jpg

http://technology.niagarac.on.ca/sop/SOP-DyeLaser.html

Stilbene 3 C102 C102 Krypton C30 C8 Rn 110 R6G Kilon Red DCM Pyridine 2 LD700 400 450 500 550 600 650 700 750 800

http://physics.nist.gov/Divisions/Div842/Gp1/laser.html