1. 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

2. 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

3. Rhodamine 6G

4. Tuning ranges of various laser dyes
Stilbene 3
C102 Argon
C102 Krypton
C30 C8
Rn 110
R6G
Kilon Red
DCM
Pyridine 2
LD700
Tuning ranges of various laser dyes

9. Stilbene 3
C102
C102 Krypton
C30 C8
Rn 110
R6G
Kilon Red
DCM
Pyridine 2
LD700