Oxygen ion laser

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The oxygen ion laser is one of the subtypes of gas lasers . These use gas or a gas mixture as an active medium , which consists of ions or molecules , to generate the laser beam . Oxygen-ion lasers in particular are triple-ionized oxygen atoms, O 3+ , which, in addition to some UV frequencies, can also emit strong lines in the yellow-green range at 559 nm. Ion lasers require large amounts of energy to excite the ions, only a small part of which is converted into light. This means that they have to be constantly cooled with water.

construction

The oxygen-ion laser consists of a tube with a mirror on one side and a semi-transparent mirror on the other. The semi-transparent mirror only lets light through in a certain polarization direction , so that the laser can emit coherent light (the laser beam). Since enormous temperatures are reached inside the laser, the tube must be made of a material that has both high thermal conductivity and high thermal shock resistance. The required properties for example, has beryllium - ceramic , but this material is toxic.

functionality

The gas as the active medium is in the tube. The ions are excited by an electrical gas discharge. After the gas has been put into a plasma state, the ions fall back into their basic state and emit light of different wavelengths. The light is reflected by the mirror and ejected as a laser beam through the semi-transparent mirror.

Multi-line configuration

In this way, the laser emits different wavelengths of light. The configuration is used, for example, when the laser beam is to have a certain color, which is made up of certain wavelengths. On the other hand, it is also possible to generate more power from the laser by bundling all wavelengths into one laser beam.

Single-line configuration

If only light of one wavelength is required, the single-line method can be used. To do this, the mirror is replaced by a prism that is mirrored on one side. The prism splits the incoming light into its spectral colors , which are reflected from the mirror side of the prism. So only the desired light gets back into the tube. The remaining wavelengths are scattered.

advantages

Gas lasers can currently produce the highest levels of radiation in the visible spectral range. The frequencies range from ultraviolet (UV) to infrared (IR). They can also generate wavelengths that other lasers cannot. Their structure is relatively simple, and even the gaseous mixture of air can be used as an active medium for low power.

disadvantage

Due to their high power, oxygen-ion lasers consume large amounts of energy and are therefore replaced by the much more energy-efficient solid-state lasers where possible . Oxygen ion lasers are rarely used, but are always used when a certain wavelength is desired or a very high laser power is required.

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