Laser

Kind of Laser

The laser is often called by name of material used as laser medium.

kind		wave length[�ʂ�]	Oscillation method	Output	Efficiency[%]	Application
Solid laser	Ruby	0.694	P		-1	Machining
	glass	1.06	P	10TW	-4	Machining�CNuclear fusion
	YAG	1.06	P CW	P:10kW CW:400W Q-switch:10MW	-3	Machining, welding
Semiconductor laser	GaAs InGaAsP	1.0	P CW	P:10W CW:100mW	-100	Communication�CMeasurement�CInformation processing
Liquid laser	dye laser	0.3-0.9	P CW	P:10W CW:1W	-0.3	Spectrum�CResearch
Gas laser	He-Ne	0.633	CW	10mW	-1	Measurement�CDisplay
	Ar	0.514 0.488	CW	10W	-0.1	Machining�CMeasurement
	excimer	0.19-0.32	P	100W	-15	Chemistry�CMedicine�CMachining�COther many
	CO2	10.6	P CW	P:10MW CW:20kW	-20	Machining�Cwelding�Cheat treating

Solid laser

The density of the solid is higher than that of the liquid and the gas. In a word, a lot of atoms will be blocked with the unit volume inside. Therefore, the output of the laser for each unit volume of Solid laser is large. Therefore, even if it is small, Solid laser is a big output.

The YAG laser is a representative of Solid laser. Because the output is large, the YAG laser is used by the laser beam machining and the laser welding. Additionally, the CO2 laser (gas laser) is used in this field.

When solid laser is continuously used, heat is accumulated in the laser medium. The laser medium expands because of this heat, and it comes to have working as the lens. Therefore, the optical path of the laser might be negatively affected. This is called the lens effect. The conduction of heat of the glass is bad. Therefore, it becomes easy to receive the influence of the lens effect especially when the glass is used as a laser medium.

Semiconductor laser

The semiconductor is a kind of the solid. However, the semiconductor is a classification in the field of the laser technology besides the solid. There are two groups of the semiconductor laser. It is the one using the III-V family semiconductor, and the one with IV-VI family semiconductor. Both, it is small and highly effective. The technology of the III-V family semiconductor is advanced.

The semiconductor laser is used for the optical communication, CD, DVD, and the laser printer, etc. When the electron and the hole are injected into the PN junction, the reversing distribution is generated.

Liquid laser

Laser that used liquid as laser medium is Liquid laser. Light is often used for excitation. Liquid laser is divided roughly into three (an organic chelate compound laser, an inorganic laser, and the organic dye laser) by the difference of the medium. However, an organic chelate compound laser and an inorganic laser have the problem of safety and efficiency.Only the organic dye laser has been put to practical use.

More than 500 kinds of media that can be used as a dye laser are confirmed. The excitation source is an ionlaser in case of a continuous oscillation. In the pulse oscillation, the flashlamp, the YAG laser, and the excimer laser are used.

Gas laser

Laser that used atom, molecule, and ion of gas as laser medium is gas laser.

In the method of exciting gas laser, the electrical discharge method is a main current. In addition, heat, the electron beam, light, and the chemical reaction are used though it is a little.

The density of the gas is lower than that of the liquid and the solid. In a word, the number of atoms in the unit volume is little. Therefore, the output of the laser for each unit volume of gas laser is small. The gas of the high pressure and the gas with large capacity are used to solve this problem.

We see red light sometimes radiated from the scanner of the POS cash register in super or the convenience store. This light is He-Ne laser that is one of the representatives of gas laser.

The CO₂ laser that used carbon dioxide as a laser medium can oscillate continuously a high output. Therefore, it is used on an industrial road (laser beam machining and laser welding) where large energy is required. The wavelength of the CO₂ laser is almost 10.6��m. The CO₂ laser cannot be looked at because the range of visible light is 0.4-0.8��m. The output of the CO₂ laser is large, and is invisibility. The great caution and measures for safety are necessary for you for handling.

There is a method of a high peaking output named TEA(Transversely Excited Atmospheric), too.

The Ar laser is a laser to which the gas of the argon ion is excited by the arc discharge. In general, the glow discharge is used for the excitation of gas laser. However, the arc discharge is used as for many of gas laser that uses the ion.

Excimer is abbreviation of excited dimer. Excimer can exist as a molecule while excited. It cannot exist as a molecule in the ground state.

<<PREVIOUS---NEXT>>

to TOP

to HOME