This page provides easy-to-understand explanations of common laser marking terms.

A to C

A/O Q switch An acousto-optic method Q-switch that changes the refractive index of light by introducing ultrasonic waves.
Alignment beam Alignment beams are auxiliary laser beams used to display the position of the primary marking beam and perform position adjustments. Since the primary marking beam is invisible, alignment beams are useful for visually confirming alignment.
Aperture A device that refines the center of a laser beam by only allowing a specific diameter of laser light to pass through.
AR coating

AR is an abbreviation for Anti Reflection.

An AR coating is applied to the laser lens to prevent reflections from occurring on the lens' surface, thus improving the transmittance of the laser beam.

Attenuator An optical component or shutter that is used to adjust the intensity or power of the laser.
Beam diameter Generally speaking, this refers to the diameter of a laser beam. Normally, this is used to specify the value of a beam center at half its peak value.
Beam divergence An angular measurement of a beam diameter's growth as it leaves the oscillator.
Beam profile A cross-sectional graph of a laser beam's power distribution.
Beam profiler Instrument to measure the distribution of intensity for laser beam.
Chiller A device that chills water and keeps it at a fixed temperature.
This is used as a secondary cooling device for water-cooled YAG lasers.
CO2 laser A laser that uses carbon dioxide as a medium and oscillates at a typical wavelength of 10.6 microns.
Complete air cooling

An air-cooling method that uses radiator fins, fans, and Peltier elements to cool down laser equipment.

A system that uses a Peltier element to conduct heat away from and cool the laser oscillator. Uses air and does not require cooling water.

Continuous wave Oscillating a seamless, continuous laser beam (CW).

D to F

Deep UV

Light with a wavelength shorter than 200 nm. Difficult to propagate outside of a vacuum.

ArF (193 nm) and F2 (157 nm) excimer lasers fall under the category of vacuum ultra-violet light.

DPSS An abbreviation for Diode Pumping Solid State. Synonymous with LD pumped solid state laser.
E/O Q switch An electro-optic method Q-switch that changes the refractive index by introducing voltage.
End pumping A method where excitation light is irradiated and energized from the rear of the laser medium. Because the center of the crystal is excited, the excitation efficiency is good, and a high quality laser beam is created.
Energy output The amount energy over time (generally measured in Watts).
Feedback light Laser light that bounces off a target surface and returns to the laser oscillator.
Fiber laser A system that uses fiber for the resonator and creates an overlapping structure with fiber cladding that has been doped with Yb ions or other elements, after which it pumps laser diode excitation light inside.
First pulse suppression Suppresses the initial giant pulse that is emitted with a Q-SW laser.
Flash lamp pumping A system that uses a lamp as the excitation source of a solid-state laser.
Focusing lens A lens (or combination of lenses) that collects and focuses light onto a target surface.
F-theta lens

A correcting lens that condenses a laser beam onto a planar surface to ensure a constant scanning speed anywhere in the marking field.

[Equation for an f-theta lens]
Lenses designed so that the relationship between the image height (h) and the entry angle (θ) equals [h=fθ]. This enables constant laser scanning speeds on the surface of a target.
Fundamental wave The wavelength of a laser beam when oscillated from the laser medium. For example, YAG lasers have a fundamental wavelength of 1064 nm.


Galvanometer mirror The mirror attached to the Galvonometer scanner.
Galvanometer scanner A stepping motor used to control the mirrors that scan the laser beam across the marking field. Its can accurately control the angle of stop rotation.
Gas laser

Laser systems that arc and discharge high voltage through a gas mixture sealed inside of a tube, changing the gas to plasma.

CO2 (carbon dioxide) and He-Ne (helium-neon) are commonly used. CO2 lasers are used for marking and processing, while helium-neon lasers are used as light sources in opto-electronics.

YAG (Yttrium Aluminum Garnet)
Fundamental wavelength (1064 nm)
  • Universal marking applications
Second-harmonic (532 nm) (Green laser)
  • Used for fine marking and processing, silicon wafers, plastics and reflective metals etc
Third-harmonic (355 nm) (UV laser)
  • Used for micro-processing, LCD repair and also plastic and reflective metal marking
Nd: YVO4 (1064 nm)
YVO4 (Yttrium Vanadate)
  • Used in applications needing high peak power and extremely stable beam power
LD: (650 to 905 nm)
  • Semiconductor lasers (GaAs, GaAIAs, GaInAs)
CO2 (10.6 μm)
  • Used for marking labels, etching plastics/resins, processing and cutting applications.
He-Ne (630 nm) (red) is common
  • Most commonly found in measurement devices.
Excimer (193 nm)
  • Uses a combination of inert gas and hydrogen gas to create a shorter UV wavelength.
    Most commonly used for optometry to vaporize the lens of human eyes.
Argon (488 to 514 nm)
  • Used primarily in scientific applications and biomedical related research.
Dye (330 to 1300 nm)
  • Used more widely in scientific applications.
    Dye are energized by laser light to produce florescent light.

The optimal laser will differ depending on the desired processing application.

Giant pulse

A pulse that possesses high-energy amplified via Q-switch.

A phenomenon where excess energy accumulation in the laser medium is released all at once, resulting in deep carved sections.

Green laser A laser that oscillates green light with a wavelength in the vicinity of 532 nm.

H to I

Harmonic generation

As a laser's wavelength becomes shorter, its energy and absorption rate generally get higher. For example, a copper plate (Cu) only absorbs 10% of fundamental (1064 nm) laser light. However, the absorption rate of UV light is 50-60%.

[How Green Lasers and UV Lasers Are Created]

Green lasers are often called second harmonic generation (SHG) lasers. 1064 nm light is passed through a single oxide crystal (LBO: Lithium Borate), and between 30-40% is converted to the 532 nm wavelength.

UV laser light is produced by combining 532 nm light with 1064 nm light and then passing both through another crystal. As a result, UV lasers are sometimes called third harmonic generation (THG) lasers. Fourth harmonic generation is referred to as D (Deep) UV and produces 266 nm light.

High reflective mirror A mirror that reflects all light within the resonator.
Infrared light Non-visible light that has a wavelength longer than 780 nm.
Inner marking Transmitting a laser beam through a transparent object such as glass to perform marking or processing on the inside of the transparent object.
Ion exchange The removal of ions and impurities generated from the water used to cool certain laser markers. This process maintains system cleanliness.



Abbreviated form of Light Amplification by Stimulated Emission of Radiation. Lasers have the following qualities:

  1. (1) Monochromaticity - A pure, single wavelength of light.
  2. (2) Excellent directionality - A parallel beam that advances without spreading.
  3. (3) High coherence - Uniform light phases.
A comparison of ordinary light and laser light
Lasers emit beams of light with high directivity, which means that the component light waves travel together in a straight line with almost no spreading apart.
Ordinary light sources emit light waves that spread apart in all directions.
The light waves in a laser beam are all the same color (a property known as monochromaticity). Ordinary light (such as the light from a fluorescent bulb) is generally a mixture of several colors that combine and appear white as a result. As the light waves in a laser beam travel, they oscillate with their peaks and troughs in perfect synchronization, a characteristic known as coherence. When two laser beams are superimposed on each other, the peaks and troughs of the light waves in each beam neatly reinforce each other to generate an interference pattern.
Directivity (light waves travel in straight line) Monochromaticity Coherence
Ordinary light
Light bulb
Many different wavelengths
Laser beam
Single wavelength
Peaks and troughs align
Laser diode Lasers created using semiconductor materials.
Laser medium

The source material that produces a laser. Laser mediums include solids, liquids and gases because different sources will produce different beam characteristics.

Gas Laser
Laser Name Oscillation Wavelength Application
Helium-Neon Laser Red/Monochrome 632.8 nm
  • Optical Axis Alignment
  • Adjusted Length Measurement
Argon Ion Laser Blue to Green
  • Optical Axis Alignment
  • Laser Printing
  • High-speed Camera Light Source
Carbon Gas Laser Infrared
10.6 µm
  • Metal Welding
  • Fusing
  • Processing
Excimer Laser Ultraviolet
126 nm to 351 nm
  • Polymer Micro-processing
  • Light Source for Academic Purposes (LIF)
Nitrogen Laser Ultraviolet
337 nm
  • Low-priced UV Laser
Solid-state Laser
Laser Name Oscillation Wavelength Application
Ruby Laser Red
694.3 nm
  • Holography
YAG Laser Red
1064 nm
  • Metal Micro-processing
  • Light Source for Academic Purposes (LIF)
  • High-speed Camera Light Source
Glass Laser Infrared
1.06 to 1.08 µm
  • Holography
Nd (Neodymium) Laser (Nd: YAG, YLF, YVO4, YAlO3) 1064 nm
1047 nm
1053 nm
  • Optical Axis Alignment
  • Laser Excitation Micro-processing
  • Stage Display Light Source
Titanium: Sapphire 660 nm to 1180 nm
  • Variable Wavelength Laser
Fiber Laser 1050 nm to 1620 nm
  • Long Distance Communication
  • High Temperature Processing
Metal Laser
Laser Name Oscillation Wavelength Application
Helium-Cadmium Laser Blue
  • Medicine
  • Laser Printing
Copper Vapor Laser Dual-wavelength
511, 578 nm
  • Stroboscopic Light Source for Highspeed Cameras
  • Uranium Enrichment Pump Laser
  • Metal Micro-processing
Gold Vapor Laser Red
  • For Medicine
  • Skin Therapy
Semiconductor Laser
Laser Name Oscillation Wavelength Application
Semiconductor Laser Red to Infrared
  • Communication
  • Solid-state Laser Excitation Light Source
  • High-speed Camera Light Source
  • Metal Processing
  • Laser Pointer Optical Pickup Light Source
Liquid Laser
Laser Name Oscillation Wavelength Application
Dye Laser 300 nm to 1200 nm
  • Variable Wavelength Laser
Laser oscillator Equipment that amplifies and oscillates a laser beam through stimulated emission from an excited state.
Laser processing

Processing performed using a laser.
Primary applications include micro-processing, welding, marking, and cutting.

Types of Laser Processing
Laser processing applications fall into three categories: removal, bonding and surface reforming.
Removal processes

Heating a material above its boiling point to evaporate parts off.

  • Cutting
    Cutting thin metallic or non-metallic objects
  • Drilling
    Drilling miniscule holes
  • Scribing
    A method of scoring materials to make them easier to separate into smaller pieces. Typically involves grooving and separating IC chips.
  • Trimming
    Removing portions of thin film. Commonly used to fine-tune semiconductors.
  • Marking
Bonding processes

Heating a material above its boiling point to cause fusion.

  • Welding
    High-speed metal welding
Reforming processes

Heating a material below its boiling point to improve it.

  • Tempering
    Improves material wear-resistance and strength
  • Vapor deposition
    Improves material wear-resistance and corrosion-resistance
Laser trimming A working process where resistor materials are trimmed to regulated resistance values.
LD An excitation method that uses a Laser Diode for the light source that excites the laser medium.
LD pumping Using a Laser Diode excitation light source to pump light into a laser producing medium.
Longitudinal mode A state where laser beams of many frequencies are oscillated depending on the distance between resonator mirrors.

M to O

M2 (M square) Specifies the quality, specifically the intensity distribution of the laser beam in the horizontal direction.
M2=1 is said to be the ideal single mode.
Multi mode A mode where the cross-section of light rays emitted from a laser oscillator appears as multiple peak points.
Optical isolator A device that possesses the ability to pass light in a single direction only. Used to block return light from a laser.
Output coupler

The mirror that passes an emitted laser beam that has been amplified within the resonator.

Oscillation Environment
In laser oscillation, a state where "the number of high-level atoms is greater than the number low-level atoms" is called population inversion.
The structure of a gas laser oscillator seals gas in. It is also equipped with an electrode that produces the charge needed in order to generate population inversion and has optical resonators installed on both sides of its tube.
Oscillation Principles
When a rated electrical current is passed through the laser tube and discharged, it creates strong plasma within the tube and that plasma collides with other atoms to create an excited state. Between optical resonators constructed from a pair of reflective mirrors that possess extremely high reflectivity for the wavelength of the laser, the light is amplified as it goes back and forth, and is reflected on one side of a reflective mirror whose reflectivity is around 99%, resulting in the external emittance of laser light.


Peak power The divided value of pulse energy and pulse width. W (watts).
Polarization plate An optical element that produces fixed-direction polarized light.
Power Amount of energy over time, in W (watts) units.
Power meter A device that measures the output of laser light.
Used to manage laser power attenuation conditions.
Protective goggles Safety goggles that are used to protect your eyes from laser beams.
Appropriate goggles are selected according to wavelength.
Pulse energy The amount of energy allotted to a single pulse from a pulse laser oscillator.
In J (joules) units
Pulse oscillation

Oscillation involving a laser light that is produced in flashes. Pulse oscillation controls laser output by changing the oscillation frequency, making it possible to increase the amount of energy per single pulse. The values that express laser output are average output, peak output, and pulse energy. Their units are W (watts) and J (joules). Compared to the output value of a continuously oscillating laser, the peak output value for a pulse laser is high. However, average output is a number value that has added the oscillation frequency to the product of pulse width and peak output, making the average output power low. Even when the average output is a few W (watts), the peak energy of a pulse laser is +10 kW (kilowatts). This gives pulse lasers energy to mark and process metals.

Peak energy
Average output of a pulse laser
Pulse Stretcher The structure or member that stretches the pulse width of a laser beam.
Pulse width The irradiation time allotted to a single pulse from a pulse laser oscillator.
Pulsed wave Oscillation of laser light at a fixed frequency. Opposite of Continuous Wave.
Pumping Adding external energy to the atoms within the laser medium and changing from a low and stable state of energy to a high state of energy.
This high state of energy is called an excited state.
Purified water Water that has been chemically and physically treated to remove dissolved substances. Purified water is used for water-cooled laser markers because it is used as an insulator.

Q to S

Q switch An optical component that places an absorber between the laser medium and output coupler and controls laser oscillation, creating high energy.
Resonator The area between the high reflective mirror and output coupler that is used to create a laser beam. Also called the cavity.
Scanning Scanning laser beams using a Galvanometer motor or other such device.
Second harmonic generation (SHG) Two times the frequency of a laser fundamental wave or 1/2 the fundamental wavelength. For a YAG laser 1/2 of 1064 nm indicates a wavelength of 532 nm (Green laser).
Seed laser The original light source.
Semiconductor laser

In short, a laser made using semiconductor material. The activation layer between the p-n junctions generates light when p-side holes combine with n-side electrons.

The semiconductor's crystal (activation layer) amplifies the light and is structured to prevent it from leaking out. Semiconductor lasers are generally used for communications, optical disks, and laser excitation sources.

The structure is very similar to a diode’s. The only difference is the use of GaAs as the host, in which the energy takes the form of light instead of heat, and changes the diode into an LED (light-emitting diode).

Short pulse laser Specifies a laser that oscillates at a pulse width of a picosecond or less.
* A picosecond is 1 trillionth of a second (10-12 seconds), and is expressed in PS units.
Shutter A light shielding plate used to block the laser beam.
Side pumping

A method where excitation light is irradiated and energized from the side of the laser medium.

A method of excitation by emitting excitation light from the area surrounding the side of the laser crystal. In this method, it is difficult to transfer heat to the center and heat cannot be transferred evenly to the whole medium.

Single mode

A laser beam that has been collected to a single point in its cross section and has the characteristics of transverse mode points.

Solid state laser A laser oscillator that creates a laser beam by irradiating the laser medium with a lamp, laser diode or other such light source.
Spatial mode A mode where the optical axis of the resonator is in a vertical direction. The cross-section of laser beam power distribution is expressed in single points in single mode, and appears as multiple-peak points in multi-mode.
Stimulated emission

A phenomenon where excited atoms are hit with light, inducing photon generation and causing a chain reaction resulting in light emission.

Atomic state
Electron state

T to Z

Third harmonic generation (THG) Three times the frequency of a laser fundamental wave or 1/3 the fundamental wavelength. For a YAG laser 1/3 of 1064 nm indicates a wavelength of 355 nm (UV laser).
Threshold The limit value of a response occurring after energy has been added to a substance. Also known as "Threshold Value".
Transverse mode Can capture the power distribution of light rays emitted from the laser oscillator in cross-section.
Ultra-violet light Non-visible light that has a wavelength shorter than 380 nm. Due to this wavelength being an effective disinfectant, it is used in food and medical related fields.
Visible light

Light that is visible to the human eye, measuring in wavelength from 380 nm to 780 nm.

What is Light?
Light is a type of "electromagnetic wave". "Electromagnetic waves" follow a standard of "wavelength" and starting from those of long wavelengths, can be divided into radio waves, infra-red rays, visible rays, ultra-violet rays, X-rays, and gamma rays.
What is Color?
As wavelengths of light hit an object, wavelengths that are reflected without being absorbed by the object are taken in by the human eye (retina). When this occurs, we recognize these wavelengths as the "color" of the object. The refractive index differs depending on the wavelength, therefore light is split. As a result, we are able to recognize a wide variety of "colors". For example, an apple reflects red wavelengths of light (600 to 700 nm) and absorbs all other wavelengths of light.
*Black objects absorb all light and thus appear black.
What is visible light?
The spectrum ranging from "red" to "purple" is referred to as "visible light". Also, longer wavelengths of light that are located in a region that is undetectable to the human eye are called "infrared light". Those on the shorter side are called "UV (ultraviolet) light".
Wave length The cyclical length of waves (wave motion) that are transmitted through the air.
YAG Yttrium Aluminum Garnet (Y3Al5O12). One type of solid-state laser medium.
It is often used as an industrial laser and supports marking on metals and plastics.
YAG laser A laser that has been oscillated by exciting a YAG crystal doped with an Nd ion using a laser diode or lamp.
YVO4 An abbreviation of Yttrium Vanadate (YVO4), a type of medium used for solid-state lasers. Often used with the end pumping method.
Oscillates a fundamental wavelength (1064 nm) laser.
YVO4 laser A laser created by exciting an Yttrium Vanadate based YVO4 crystal doped with an Nd ion using an LD or lamp.
Znse Zinc Selenide. Used in CO2 laser lenses because it is an optical crystal that transmits far-infrared rays.