Dye lasers use an organic dye as the lasing medium, usually in liquid solution, which allows lasing over a wide range of wavelengths. The dye molecules absorb light, becoming electronically excited into a singlet state, and then fluoresce to emit stimulated radiation. Within microseconds, the molecules transition to a triplet state where they absorb light and inhibit lasing. Flashlamp or external laser pumping provides enough energy before triplet absorption occurs. Dye lasers require pumping light, mirrors to oscillate fluorescence, and a prism or grating to tune the wavelength output.

1. MOHD FAIZ ‘IZZUDDIN B ZAMURI
MOHD ZAIRUL IZDWAN B ZULKIFLI
MUHAMMAD HAFIZUDDIN B MOHAMAD AMINUDDIN
MOHD ASYRAF B AZEMI
FAIZZWAN B FAZIL

2. A laser which uses an organic dye as the lasing medium, usually as
a liquid solution. A dye can usually be used for a much wider range
of wavelengths

3. The dyes used in these lasers contain rather large organic
molecules which fluoresce. The incoming light excites the dye
molecules into the state of being ready to emit stimulated radiation,
the singlet state.
In this state, the molecules emit light via fluorescence, and the dye
is transparent to the lasing wavelength. Within a microsecond, or
less, the molecules will change to their triplet state.

4. In the triplet state, light is emitted via phosphorescence, and the
molecules absorb the lasing wavelength, making the dye opaque.
Liquid dyes also have an extremely high lasing threshold.
Flashlamp pumped lasers need a flash with an extremely short
duration, to deliver the large amounts of energy necessary to bring
the dye past threshold before triplet absorption overcomes singlet
emission.
Dye lasers with an external pump laser can direct enough energy
of the proper wavelength into the dye with a relatively small amount
of input energy, but the dye must be circulated at high speeds to
keep the triplet molecules out of the beam path.

6. All dye lasers share the same active medium,they differ
widely in internal structure.
The pump source strongly influences design of dye laser
because of the energy transfer kinetic of the dye
The upper laser level has a lifetime of a few
nanoseconds,making the pulsedye laser a high gain high
loss system when it is pumped by pulses with high peak
power.
Pumping is more difficult with a continuous wave laser
which does not generate high peak power in pulses
To reach the high power densities needed to exceed laser
threshold, the moderate power beam from continuous
wave pump laser must be focused very
tightly,concentrating its power in a small volume.
The continuous wave pumped dye laser remains a low
gain low loss system .
Mode locking or cavity dumping allow a continuously
pumped dye laser to generate pulsed output.

7. flashlamp or an external laser is usually used for “pump”
purpose.
Mirrors are also needed to oscillate the light produced by the
dye’s fluorescence, which is amplified with each pass through the
liquid.
prism or diffraction grating is usually mounted in the beam path,
to allow tuning of the beam. (which consists of two mirrors, which
may be flat or curved, mounted parallel to each other with the laser
medium in between. Tuning is used to adjust the wavelength)
The dye cell is usually side-pumped, with one or more flashlamps
running parallel to the dye cell in a reflector cavity. (dye-container)
dye is a colored substance that has an affinity to the substrate to
which it is being applied as lasing medium
(ex: Rhodamine 6G)

8. The reflector cavity is often water cooled, to prevent thermal
shock in the dye caused by the large amounts of near-infrared
radiation which the flashlamp produces.
output coupler (OC) is a partially reflective mirror used in lasers to
extract a portion of the laser beam from the optical resonator.
etalon forms the basis of wavelength locking system that can be
used to stabilized the wavelength of a laser
Beam expanding optic illuminates the whole width of a diffraction
grating
A cylindrical lens (focusing optic) is used to focus light which
passes through on to a line instead of on to a point

9. Low cost
Tuning possible with multiple means
No degradation of the optical properties of
the organic dye
More robust and compact systems

10. limited lifetime.
limited output power