Laser optics is a very helpful tool in laser application. If designed and applied correctly, they can help to achieve a 100% transmission rate. Laser optics should be of very high quality. To guarantee this quality, there are several features that laser optics should have, each carefully adapted to the goal of the laser.
Keep on reading to find out what laser optics are and what quality requirements they should adhere to.
What Are Laser Optics?
Laser optics are applied to optical elements and systems that use lasers. They are used to transmit, focus, filter, redirect or manipulate laser light. Light from a laser is usually more intense than a normal light source and moves uni-directional. Laser optics are designed for the purpose of the instrument it is applied to. Since each instrument is different, each laser optic is different as well. For example, optics for a 266nm laser may not fit a 1064nm laser. There are lots of instruments and applications that use laser optics.
A good overview of the different kinds of laser optics can be found at https://www.pleiger-laseroptik.de/en/. Some examples are as follows:
- Laser mirrors (redirects and distributes beams)
- Laser lenses (focused beams)
- Laser windows (protects optical equipment)
- Laser filters (improve quality or intensity of the beam)
- Laser beamsplitters (splits laser beams into several beams)
Requirements of Laser Optics
Laser optics have a very short bandwidth and power. They are much more complex than regular light and therefore need special laser optics. Normal optics will not work properly with laser light. Laser optics usually need to be of impeccable quality and simple glass won’t always be enough. It is therefore held to the highest standard regarding quality.
Laser-Induced Damage Threshold (LIDT)
Laser Induced Damage Threshold refers to the amount of energy that an optical element can take without damage. It is expressed in J/cm2. This LIDT is important for high-power lasers and should be designed for a certain wavelength. During the designing process, it is important to know whether the laser is CW or Pulsed.
Laser optics try to achieve a 100% transmission rate. To reach this perfect rate, a number of things can be done: For example, the material that is used to make the laser optics should be very pure. Lasers will destroy impurities and therefore damage the glass. The optics should also be polished very well to reduce adsorption. Also, the element should be clean at all times, and should preferably be cleaned in clean rooms.
Another very important thing is to add a coating to the optics. Anti-reflection coating helps tremendously to improve transmission. The best coating is an IBS coating because it can enable a higher layer density.
Laser Optics Material
There are a handful of materials that are most suitable for manufacturing laser optics. Since laser optics should be made of pure material, manufacturing them is not an easy task. The most common material that is used to produce laser optics is fused silica. This material is praised for its purity, as it is more than 99,99% pure. The chance that laser optics made with this material will deteriorate because of impurities is less than 1%.
Other materials that are often used for the production of laser optics are CaF2 Nd (high LIDT and is therefore used for high-power lasers), MgF2 (UV and Excimer lasers), and N-BK7/ H-K9L (cannot be used for high power lasers).
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