Types of Lasers: 8 Common Classifications of Laser

Light wavelength distribution map

Green lasers, also known as second-harmonic lasers, are notable for their specialized ability to process at a micron level. The laser begins at a 1064 nm wavelength and then passes through a nonlinear crystal for conversion into a 532 nm wavelength. With the much shorter wavelength that appears green to the human eye, intricacy is a green laser's special power. Green lasers are used as pointing devices and for micron-level marking and processing.

UV lasers, also known as third-harmonic lasers, are a specialized type of solid-state laser that uses “cold marking.” Cold marking refers to a UV laser's strength of absorption that produces very little heat when marking. These lasers start at a 1064 nm wavelength and then pass through two nonlinear crystals to transition to a 355 nm wavelength.

Because of the extremely small beam, small processing and minimal damage are two key components of a UV laser. UV lasers are powerful enough to create high contrast marks on highly reflective materials like copper, gold, and silver.

Solid-state fiber lasers are highly regarded for their high average power, fast speed, and excellent cooling efficiency. With the ability to mark on metal, plastic, and ceramic with a 1030-2100 nm wavelength, it's even more impressive that fiber lasers can engrave, anneal, mark, etch, cut, and remove burrs. Fiber lasers have the smallest marking unit size, making them the easiest to retrofit or integrate in production settings with limited space.

Fiber systems handle demanding production schedules without frequent downtime. The sealed optical path prevents contamination that plagues open-beam configurations. Operators spend less time on calibration and more time running parts. Metal marking applications benefit from fiber technology's ability to create permanent, high-contrast identification codes that withstand harsh environments.

Fiber lasers have an edge over earlier technologies due to their energy efficiency. Wall-plug efficiency is 30%, while CO₂ systems have an efficiency of 10%. Over the course of the equipment's lifetime, lower power consumption results in lower operational expenses. Facilities also appreciate the reduced cooling requirements, which simplify installation planning.

CO₂ gas lasers have the longest wavelength compared to fiber, YAG, and YVO₄. CO₂ lasers have a wavelength of 10600 nm. Because of the long wavelength, there is more heat transfer than other lasers. Moreover, CO₂ lasers are commonly used for cutting materials.

CO₂ lasers excel at cutting plastic materials and processing organic compounds. Their longer wavelength generates more heat, which penetrates materials differently than shorter wavelengths. These systems require proper ventilation and gas supply management for optimal performance.

Packaging industries rely on CO₂ technology for laser marking dates, lot codes, and graphics on cardboard, wood, and paper products. The infrared beam creates clean marks without contact, preventing material distortion. Food and beverage manufacturers use these systems for expiration date coding on bottles and containers.

Maintenance requirements include periodic gas refills and mirror alignment checks. Optics cleaning schedules depend on environmental conditions in the production area. Dust and airborne particles can degrade beam quality if not properly managed.

He-Ne gas lasers have a wavelength of 630 nm and appear red to the human eye. He-Ne lasers are commonly known for their use as pointing devices in classrooms or during presentations. These laser types are also used in store barcode scanners and measurement devices. Unlike many other types of lasers, He-Ne lasers do not do manufacturing processing.

He-Ne systems offer affordability for basic applications but lack the power needed for heavy manufacturing. Their visible red beam makes alignment and setup straightforward for operators.

Surveying and construction teams use He-Ne lasers for establishing level reference lines across job sites. The stable, continuous beam maintains accuracy over long distances. Machine tool manufacturers incorporate these lasers into equipment for precision positioning tasks.

Excimer gas lasers use inert gas and hydrogen gas to produce a short UV wavelength of 193 nm. These lasers are commonly used for dermatology and optometry treatments. In fact, excimer lasers are proven to treat skin conditions like alopecia, psoriasis, leukoderma, and more. These lasers are also used in optometry to vaporize the lens of human eyes.

Excimer technology is essential to photolithography procedures in semiconductor fabrication. The short wavelength makes it possible to transfer patterns at the nanoscale sizes needed for contemporary microchips. This level of precision in laser etching propels advancements in processing power and device downsizing.

Similar to excimer lasers, argon gas lasers are also used for various health conditions, scientific applications, and biomedical research. Argon lasers use a 488 to 514 nm wavelength, and one popular type of argon laser treatment is for glaucoma or diabetic eye disease treatment.

Research laboratories employ argon lasers for fluorescence microscopy and flow cytometry. The blue-green output excites fluorescent markers in biological samples. Spectroscopy applications take advantage of the pure wavelength for chemical analysis work.

Dye lasers are liquid lasers with a wavelength of 330 to 1300 nm, commonly used for scientific applications. These lasers use organic liquid dyes to power their wavelengths and produce fluorescent light.

Tunable wavelength capability sets dye lasers apart from fixed-wavelength systems. Researchers adjust output across a broad spectrum by changing dye solutions. This flexibility supports diverse experimental needs without purchasing multiple laser types. Academic institutions value this adaptability for teaching and investigation purposes.