CO2 Laser Engraving and Cutting Machine
The active laser medium (laser gain/amplification medium) is a gas discharge which is air or water cooled, depending on the power being applied. The filling gas within the discharge tube consists of around 10–20% carbon dioxide (CO2), around 10–20% nitrogen (N2), a few percent hydrogen (H2) and/or xenon (Xe) (usually only used in a sealed tube), and the remainder of the gas mixture helium (He) The specific proportions vary according to the particular laser.
The population inversion in the laser is achieved by the following sequence: electron impact excites vibrational motion of the nitrogen. Because nitrogen is a homonuclear molecule, it cannot lose this energy by photon emission, and its excited vibrational levels are therefore metastable and relatively long-lived. Collisional energy transfer between the nitrogen and the carbon dioxide molecule causes vibrational excitation of the carbon dioxide, with sufficient efficiency to lead to the desired population inversion necessary for laser operation. The nitrogen molecules are left in a lower excited state. Their transition to ground state takes place by collision with cold helium atoms. The resulting hot helium atoms must be cooled in order to sustain the ability to produce a population inversion in the carbon dioxide molecules. In sealed lasers, this takes place as the helium atoms strike the walls of the container. In flow-through lasers, a continuous stream of CO 2 and nitrogen is excited by the plasma discharge and the hot gas mixture is exhausted from the resonator by pumps.
Because the energy levels of molecular vibration and rotation are similar, the photons emitted due to transition between these levels have comparatively low energy, and longer wavelength, than visible and near-infrared light. The 9-12 μm wavelength of CO 2 lasers is useful because it falls into an important window for atmospheric transmission (up to 80% atmospheric transmission at this wavelength), and because many natural and synthetic materials have strong characteristic absorptions in this range.
Because CO 2 lasers operate in the infrared, special materials are necessary for their construction. Typically, the mirrors are silvered, while windows and lenses are made of either germanium or zinc selenide. For high power applications, gold mirrors and zinc selenide windows and lenses are preferred. There are also diamond windows and lenses in use. Diamond windows are extremely expensive, but their high thermal conductivity and hardness make them useful in high-power applications and in dirty environments. Optical elements made of diamond can even be sand blasted without losing their optical properties. Historically, lenses and windows were made out of salt (either sodium chloride or potassium chloride). While the material was inexpensive, the lenses and windows degraded slowly with exposure to atmospheric moisture.
The most basic form of a CO 2 laser consists of a gas discharge (with a mix close to that specified above) with a total reflector at one end, and an output coupler (a partially reflecting mirror) at the output end.
The CO 2 laser can be constructed to have continuous wave (CW) powers between milliwatts (mW) and hundreds of kilowatts (kW).  It is also very easy to actively Q-switch a CO 2 laser by means of a rotating mirror or an electro-optic switch, giving rise to Q-switched peak powers of up to gigawatts (GW).
Because the laser transitions are actually on vibration-rotation bands of a linear triatomic molecule, the rotational structure of the P and R bands can be selected by a tuning element in the laser cavity. Prisms are not practical as tuning elements because most media that transmit in the mid-infrared absorb or scatter some of the light, so the frequency tuning element is almost always a diffraction grating. By rotating the diffraction grating, a particular rotational line of the vibrational transition can be selected. The finest frequency selection may also be obtained through the use of an etalon. In practice, together with isotopic substitution, this means that a continuous comb of frequencies separated by around 1 cm −1 (30 GHz) can be used that extend from 880 to 1090 cm −1. Such “line-tuneable” carbon dioxide lasers are principally of interest in research applications.
One facet of output wavelength is due to the particular isotopes contained in the carbon dioxide molecule. Since various combinations of isotopes can produce wavelengths from 8.98 to 10.2 μm, precision laser fabricators must take this factor into account when selecting the gas for their products.
Industrial (cutting and welding)
Because of the high power levels available (combined with reasonable cost for the laser), CO 2 lasers are frequently used in industrial applications for cutting and welding, while lower power level lasers are used for engraving.
Medical (soft-tissue surgery)
Carbon dioxide lasers have become useful in surgical procedures because water (which makes up most biological tissue) absorbs this frequency of light very well. Some examples of medical uses are laser surgery and skin resurfacing (“laser facelifts”, which essentially consist of vaporizing the skin to promote collagen formation).  CO 2 lasers may be used to treat certain skin conditions such as hirsuties papillaris genitalis by removing bumps or podules. CO 2 lasers can be used to remove vocal fold lesions such as vocal fold cysts. Researchers in Israel are experimenting with using CO 2 lasers to weld human tissue, as an alternative to traditional sutures.
The CO 2 laser remains the best surgical laser for the soft tissue where both cutting and hemostasis are achieved photo-thermally (radiantly).CO 2 lasers can be used in place of a scalpel for most procedures, and are even used in places a scalpel would not be used, in delicate areas where mechanical trauma could damage the surgical site. CO 2 lasers are the best suited for soft tissue procedures in human and animal specialties, as compared to other laser wavelengths. Advantages include less bleeding, shorter surgery time, less risk of infection, and less post-op swelling. Applications include gynecology, dentistry, oral and maxillofacial surgery, and many others.
Sealed Fiber Laser Marking Machine
With fiber lasers, the benefits can be blinding. But what users think they want and what actually they need can be two different things. While there are compelling reasons to choose fiber lasers and the trend is ever more bucking in their direction, it’s worth remembering that sometimes the older alternatives offer a better solution. Lamp pump lasers are still great for laser welding; the wavelength of light from CO 2 lasers is still great for laser cutting certain materials; and, even when it comes to marking, other laser technologies can perform better with plastics. It’s all about the task at hand.
MOPA Laser Machine
The term MOPA is actually an acronym for Master Oscillator Power Amplifier. This type of technology was a breakthrough in DUV (Deep Ultraviolet) light source design. In traditional, single-chamber light sources, there is a trade-off between bandwidth and power, forcing you to choose between compromising performance or cost effectiveness. But with MOPA technology, you no longer have to compromise. The MOPA design has two gas discharge chambers: the master oscillator and the power amplifier. The master oscillator generates light with a low amount of energy in a tight spectrum. From this point, the light is then passed through the second chamber, the power amplifier, which intensifies the light to reach the necessary power levels.
The difference between traditional TIG and micro welding is that micro welding is done at extremely low amperage (usually less than 10 amps) in combination with fine control of the amperage range, along with the aid of a high-powered (10X-20X or more) microscope. In the micro welding process, the technician performing the weld repair – in combination with the welding equipment controls and the weld wire selection – is absolutely critical to the end result.
UV Laser Machine
The UV marking lasers with a wavelength of 355 nm are suitable for marking plastics but also for typical laser marking applications and micromaterial processing. The wavelength permits very small spot diameters and thus character heights < 100 μm. Due to the high repetition rates, ITI UV lasers are highly suitable for marking plastics (ABS, PA) at extremely high processing speeds, as required for rapid industrial production processes, as well as high-precision marking/structuring on glass and/or ceramics with high peak performance without thermal impact.