Maintenance and cleaning of the femtosecond laser optical path

Laser light path:

  Laser optical path is commonly known as the laser propagation path, in practice, the laser 80% can not be directly satisfied with the application requirements, so the need to deploy a variety of optical components. 

  Common optical components in the laser light path are beam expanders, optical mirrors, mirrors, field mirrors and so on.

Optical path problems may form the results:

  1. Laser energy attenuation: common problem, the optical path in the optical lens is dirty, the transmittance becomes larger, the overall attenuation becomes larger, resulting in the final processing power becomes lower;

  2. Aggregate spot quality deterioration: spot becomes ellipsoid, spot energy distribution is uneven;

  3. Multi-focal point: the collimation of the optical path is not calibrated well, and defocus occurs;

  4. Thermal drift: the academic equipment has advantages and disadvantages, the degree of heat deformation is different, the severity of the thermal drift phenomenon is also different.

Optical path protection and maintenance approach:

  The maintenance of the optical path, mainly for the maintenance of optical components on the optical path, optical components are very weak, in order to reach a higher level of functionality and life in the use of special procedures must be followed. In daily use, optical components will touch dust, water vapour and skin oil and other dirt. These contaminants improve the scattering of the optical surface and also absorb the incident light, creating a hot spot on the optical surface, which can lead to sexual damage. Coated optics are particularly susceptible to this damage.

Never handle the optics directly during operation, as skin grease may damage the optical surface. The correct practice is to wear gloves. For smaller optics, it is easier to use optical tweezers or vacuum tweezers. No matter what way to hold the optical components, if possible, can only hold the non-optical appearance, such as frosted edges.

 I. Blow-wiping the exterior of the optics

Before doing any other cleaning techniques, generally need to blow away dust and other loose contaminants. This approach requires the use of a lazy dusting gas canister or perhaps a blower ball. Do not blow directly into the optics with your mouth, as it will probably deposit saliva on the optics.

If you are using lazy dusting gas, keep the canister in the upright position before and throughout the application. Note: Do not shake the canister before or during use.

Please refer to the following items:

  1. Aim the nozzle far away from the optics before blowing. These steps help prevent lazy gas propellant from being deposited on the optical surface.

  2. If you are using filled gas, hold the canister approximately 6 inches away from the optics and use a short blowing method.

  3. Turn the nozzle of the lazy gas canister so that its nozzle and the optical components of the exterior form a swept angle blowing.

  4. For the large size of the optical element appearance, in the optical appearance along the following figure style blowing.

Because this cleaning method has no touch and no solvent characteristics, it should be used as almost all optical components clean the first step.

Second, cleaning optical components

If approved by the manufacturer, fingerprints and large dust particles can be removed by immersion in distilled water and optical soap. Optical components should not be soaked longer than necessary to remove contaminants. Afterwards, the optics are cleaned with clean distilled water.

Depending on the type of optics, you can choose the drag-and-drop scrubber (applicator) method, and apply acetone, methanol, or another fast-drying solvent to the optics to accelerate drying. In the drying process to prevent the formation of small droplets of cleaning solvents, as this often leaves water stains on the optical surface.

Third, drag method

Drag method can be used to clean any of the above mentioned appearance of the flat optical appearance.

The following steps can be seen:

1. Check the optics and confirm the position of the contaminants. This will enable you to plan the direction of the drag beforehand, which will help to dab the contaminants from the exterior of the optics as soon as possible, rather than dragging them across the exterior of the optics.

2. After checking, place and hold the optic firmly so that the lateral force on the exterior is weak and does not cause the optic to move. Take a new, clean piece of lens paper and place it on top of the optic (without touching it) so that it will skim over the exterior of the optic when you pull on the lens paper.

3. Then put one or two drops of rapidly evaporating solvent on the lens paper and place it over the optics. The weight of the solvent will cause the lens paper to sag and touch the optical surface. Slowly and evenly pull the wet lens paper across the exterior of the optics, taking care to prevent the lens paper from pulling up on the exterior. Keep pulling the lens paper until it leaves the optical surface.

The correct amount of solvent will keep the lens paper wet throughout the drag and will not leave any visible solvent marks on the optical surface when the drag is complete. Check the optics and repeat if necessary, but only use each lens paper once!