MOHD FAIZ ‘IZZUDDIN B ZAMURI

MOHD ZAIRUL IZDWAN B ZULKIFLI

MUHAMMAD HAFIZUDDIN B MOHAMAD AMINUDDIN

MOHD ASYRAF B AZEMI

FAIZZWAN B FAZIL

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

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.

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.

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.

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)

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

Low cost

Tuning possible with multiple means

No degradation of the optical properties of

the organic dye

More robust and compact systems

limited lifetime.

limited output power