Visible Lasers
Author: the photonics expert Dr. Rüdiger Paschotta (RP)
Definition: lasers (or other laser-based light sources) emitting visible light
More general term: lasers
More specific terms: red lasers, yellow and orange lasers, green lasers, blue lasers
Categories:
DOI: 10.61835/9e4 Cite the article: BibTex plain textHTML Link to this page LinkedIn
The term visible lasers is used to denote lasers emitting visible light, or sometimes laser devices generating visible light via nonlinear frequency conversion. Visible light (for human eyes) corresponds to optical wavelengths roughly between 400 nm and 700 nm.
Lasers with Direct Visible Emission
Laser which directly emit visible light constitute a minority – most lasers emit in the infrared spectral region. Some examples of solid-state lasers emitting visible light are:
- Various laser diodes can emit visible light. Examples are GaInP and AlGaInP-based red laser diodes, and GaN-based blue-emitting diodes.
- The first demonstrated laser was a ruby laser emitting at 694.3 nm.
- titanium–sapphire lasers emit mostly in the infrared spectral region, but can be tuned down to roughly 650 nm.
- There are various upconversion lasers, including both bulk and fiber lasers, with visible light emission.
There are also various gas lasers emitting visible light:
- The helium–neon laser was the first gas laser with visible emission. It can emit on various visible wavelengths, including the well-known 632.8 nm red wavelength but also in the green (543.5 nm), yellow (594.1 nm) and orange (604.6, 611.9 nm) spectral region.
- helium–cadmium lasers (→ metal vapor lasers) emit in the blue at 441.6 nm.
- Argon ion lasers emit mostly at 514.5 and 488 nm, but also at 465.8, 472.7 and 528.7 nm.
- Krypton ion lasers emit at various wavelengths throughout the visible spectrum, in particular at 647.1 nm and 530.9 nm.
- Copper vapor lasers (→ metal vapor lasers) emit at 510.6 nm (green) or 578.2 nm (yellow).
Finally, various dye lasers have broad emission ranges throughout the visible spectral region.
See also the articles on red, green and blue lasers.
Visible Laser Systems Based on Nonlinear Frequency Conversion
Various methods allow the generation of visible light in laser diodes via nonlinear frequency conversion:
- The most frequently used approach particularly for green and blue emission is frequency doubling, either intracavity or in an external nonlinear crystal (single-pass or resonant). This can be applied to traditional solid-state bulk lasers and also to VECSELs. Most common are green-emitting laser sources based on frequency-doubled 1064-nm neodymium lasers.
- Sum frequency generation in a nonlinear crystal can generate visible light. For example, sum frequency mixing of a 1064-nm Nd:YAG laser and a 1.5-μm fiber laser leads to red light.
- A Raman laser can be pumped with light from a regular laser. This is most often done with solid-state bulk lasers, which may be Q-switched or continuous-wave, and often intracavity frequency doubled.
- For broadband visible radiation, there are laser sources involving supercontinuum generation.
Applications of Visible Lasers
Some examples of applications of visible lasers:
- Laser pointers and various alignment lasers should emit in the visible range, as otherwise it would be more difficult to track the beam.
- Laser scanners, LIDAR and interferometry are partially done with visible lasers. For holography, it is also common.
- There are laser-based displays, e.g. based on RGB sources.
- In some applications, one requires short wavelengths (shorter than for infrared light) to excite fluorescence of some substances. Examples are fluorescence microscopy and flow cytometry.
- Short wavelengths also greatly increase the amount of light scattering, which can be useful, for example, in laser Doppler velocimetry and other types of sensors, e.g. in optical computer mice.
- Laser surgery partially uses visible lasers. Photodynamic therapy is another example in the medical area.
- In applications like optical data storage, the shorter wavelengths of visible light are beneficial for focusing to small points and thus reaching a high data density.
More to Learn
Encyclopedia articles:
Suppliers
The RP Photonics Buyer's Guide contains 125 suppliers for green lasers. Among them:
CNI Laser

CNI offers different kinds of green lasers, including both diode lasers and diode-pumped solid-state lasers:
- Green diode lasers are available with wavelengths of 505 nm, 510 nm, 514.5 nm and 520 nm.
- Pulsed solid-state green lasers offer a narrow pulse width of <0.8 ns and pulse energies >450 mJ. We also have high-power versions with >200 W, highly stabilized lasers with <0.1% stability and <0.25% RIN, and single longitudinal mode green lasers with a line width <0.00001 nm.
Our green lasers are widely used in holographic photography, PIV particle velocity, Raman spectra, Lidar and other fields.
Lumibird

Lumibird manufactures green lasers obtained by frequency doubling process, both on our pulsed fiber lasers and on our pulsed nanosecond solid-state lasers.
Advanced Photonic Sciences

APS offers the MicroGreen™ Series, which is a diode-pumped solid-state laser packaged in a 5.6 mm diameter can. The MicroGreen is available in power ratings up to 80 mW in TEM00 mode. The alignment-free optical design is also both rugged and reliable; and its high optical-to-optical conversion efficiency allows the laser to be battery powered. Applications include tool alignment, machine vision, aiming guide, and the green color source in micro-displays.
Monocrom

Monocrom offers different green lasers:
- Multi-Path 532: a photocoagulation laser emitting up to 8 W cw or 15 W qcw at 532 nm
- CiOM lasers emitting nanosecond pulses at 526.5 nm
Edmund Optics

Edmund Optics offers different kinds of green lasers, including argon-ion lasers, diode lasers and diode-pumped solid-state lasers.
AdValue Photonics

AdValue Photonics offers the EVERESTpico green picosecond laser for applications like laser cutting, drilling and scribing on various materials. Different models can deliver 50-ps pulses with up to 30 W average power and excellent beam quality.
Vexlum

VEXLUM offers VECSEL technology with intracavity frequency doubling, producing diffraction-limited, watt-level lasers across the green spectral region (500–570 nm). The lasers feature a wavelength tuning range of ±1 nm and a narrow linewidth, ideal for various applications:
Quantum technology:
- Cs Rydberg state preparation 509 nm
- Yb macic wavelength 552 nm
- Ba MOT 553.5 nm
- Yb 2nd stage narrow cooling 556 nm
- Yb clock 578 nm
Medical applications:
- Ophthalmology: retinal photocoagulation (520 or 532 nm)
TOPTICA Photonics

Nonlinear frequency conversion techniques access wavelengths that cannot be generated directly from laser diode technology. Via second or fourth harmonic generation, TOPTICA laser systems can access the UV, blue, green, yellow and orange spectral ranges at high powers. TOPTICA offers tunable, single-frequency systems at virtually any wavelength between 190 nm and 780 nm, employing ultrastable seed lasers, power amplification in semiconductor or fiber amplifiers, and a proprietary bow-tie cavity design – all in established pro technology.
Teem Photonics

The latest release, PicoSpear Amplified Microchip Series, produces ultra-short pulses, as short as 650 picoseconds, and maintains a high output power adjustable up to 500 mW.
Compact models of the passively Q-switched range, such as the SNG-40F-1x0 laser, with average output powers between 15 mW and 100 mW and different pulse repetition rates.
Triggered lasers include the STG-03E-1x0 laser, a short pulse laser available also with green output.
Sacher Lasertechnik

Sacher Lasertechnik has developed a frequency-doubled laser system where a resonant cavity including a frequency doubler crystal is pumped via a tunable diode laser. Depending on the required SHG power, the tunable diode laser is either a high power external cavity laser, or a two stage Master Oscillator Power Amplifier System. The covered wavelength regime ranges from 365 nm up to 540 nm.
RPMC Lasers

Serving North America, RPMC Lasers offers a wide range of green laser diodes and green DPSS lasers. We offer pulsed and CW lasers and modules, including single emitters, laser diode & line modules, HeNe lasers, CW & pulsed DPSS lasers, ultrafast lasers, microchip lasers, MIL-spec lasers, and more, with output powers from 500 µW up to 50 W, with packaging options for all levels of integration from TO can through turnkey systems. Standard and custom options available. Let RPMC help you find the right laser today!
HÜBNER Photonics

HÜBNER Photonics offer green diode pumped lasers (DPLs) emitting at 532 nm. They exhibit single longitudinal mode operation with very low noise and excellent power stability and come with a 24-months warranty.
Frankfurt Laser Company

Frankfurt Laser Company offers green laser diodes with emission wavelengths from 500 nm to 570 nm.
2020-06-18
How does the laser in a digital cinema projector work?
The author's answer:
There are different technical approaches. For example, they may use a powerful infrared laser combined with nonlinear frequency conversion to get red, green and blue light – see the article on RGB sources.