Green Lasers

Dr. Rüdiger Paschotta

Green Lasers

Author: the photonics expert Dr. Rüdiger Paschotta (RP)

Definition: lasers emitting in the green spectral region

More general term: visible lasers

Category: article belongs to category laser devices and laser physics laser devices and laser physics

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DOI: 10.61835/lcy Cite the article: BibTex plain text HTML Link to this page! LinkedIn

This article concerns lasers emitting in the green spectral region, i.e., with a wavelength roughly around 510–570 nm. The choice of laser gain media for such wavelengths is limited, and the performance achievable is typically not as good as e.g. in the infrared spectral region. Nevertheless, green-emitting lasers of various kinds belong to the most often used visible lasers. Some of them are based on nonlinear frequency conversion, namely frequency doubling.

Types of Green Lasers

There are many types of green lasers, which differ substantially e.g. in terms of output power, pulse format and cost:

Argon ion lasers, based on amplification in an argon plasma (made with an electrical discharge), are fairly powerful light sources for various wavelengths. The highest power can be achieved in green light at 514.5 nm. It can exceed 20 W, but the power efficiency of such lasers is very poor, so that tens of kilowatts of electric power are required for multi-watt green output, and the cooling system has corresponding dimensions. There are smaller tubes for air-cooled argon lasers, requiring hundreds of watts for generating some tens of milliwatts. The beam quality can be close to diffraction-limited.
helium–neon lasers are most well known as red lasers, but they can also be made to emit a few milliwatts at 543.5 nm.
Copper vapor lasers can emit relatively high powers at 510.6 nm. They are based on a pulsed discharge in copper vapor and emit nanosecond pulses.
Green laser diodes (or other green semiconductor lasers) are difficult to produce – even more difficult than blue ones. They can emit only a few milliwatts and have relatively short lifetimes, compared with other laser diodes [5]. However, there has been encouraging progress recently [10, 11].
Erbium-doped upconversion lasers based on erbium-doped fibers or bulk crystals can emit around 550 nm, typically with some tens of milliwatts of output power and with high beam quality.
Praseodymium-doped lasers can emit green light (e.g., Pr³⁺:YLF at 523 nm), apart from light at various other wavelength. They can be pumped with blue light from laser diodes, for example.

Figure 1: Photograph of the VERDI green laser from Coherent. This device contains a diode-pumped vanadate laser with intracavity frequency doubling. The image was kindly provided by Coherent.

There are various types of frequency-doubled solid-state lasers, where the actual laser emits in the 1-μm spectral region and a frequency doubler (based on a nonlinear crystal material such as LiNbO₃, LBO or KTP) converts this radiation into green light. The frequency doubling process can take place either outside the laser or within the resonator. Most common is an output wavelength of 532 nm, obtained by doubling 1064-nm radiation from a neodymium-doped 1064-nm Nd:YAG laser or Nd:YVO₄ laser, and 515 nm from doubling the output of a 1030-nm Yb:YAG laser. Figure 1 shows an example. Output powers of multiple watts can be easily obtained, even with single-frequency operation and high beam quality. Hundreds of watts of green light are generated with some high-power lasers. Fiber lasers are also interesting sources, in particular when their ability to produce somewhat different wavelengths is relevant. For smaller powers, frequency-doubled microchip lasers or laser diodes (e.g. for green laser pointers) can be used (sometimes with pulsed pumping or with a semiconductor optical amplifier for increased power efficiency of the frequency doubler).
High-power optically pumped VECSELs are also very attractive laser sources for frequency doubling with several watts or even tens of watts of output power [8]. For lower powers, semiconductor DFB lasers can be used. Note that other kinds of semiconductor lasers, such as broad area laser diodes, are less suitable for frequency doubling due to a typically broader linewidth and poor beam quality.
There are dye lasers which can be operated in the green spectral region with wide tunability.

green high-power laser — Figure 2: A high-power thin disk laser with intracavity frequency doubling generates 1.3 kW of green light with excellent efficiency. Source: Max Kovalenko, Institut für Strahlwerkzeuge, Stuttgart.

Applications

Green lasers are used e.g. as laser pointers, for laser projection displays (as part of RGB sources), for printing, in interferometers, bioinstrumentation, medical scanning, and for pumping of solid-state lasers (e.g. titanium–sapphire lasers).

In laser material processing, green lasers (when compared with near-infrared lasers) can bring benefits via a much higher absorption coefficient e.g. in copper, gold, or silicon. That way, one can work with substantially less laser power, and the processing results are also often substantially better in terms of quality. Therefore, the substantially higher cost per watt is often well justified.

Suppliers

The RP Photonics Buyer's Guide contains 127 suppliers for green lasers. Among them:

Lumibird

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

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.

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.

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.

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.

Edmund Optics

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

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.

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 2^nd stage narrow cooling 556 nm
Yb clock 578 nm

Medical applications:

Ophthalmology: retinal photocoagulation (520 or 532 nm)

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.

Osela

Osela's green laser products combine high visibility with excellent beam quality for versatile machine vision, bioinstrumentation, visual alignment applications. Typically operating around 520 nm, our green lasers offer a balance between the resolution advantages of blue lasers and the lower power requirements of red lasers. These modules are particularly well-suited for applications such as DNA sequencing, fluorescence microscopy, and industrial alignment. Featuring Osela's proprietary beam shaping technology, our green lasers can be customized with various output patterns and power levels to meet the diverse needs of OEM integrators and end-users in both life sciences and industrial sectors.

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

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.

RPMC Lasers

Serving North America, RPMC Lasers offers high-performance pulsed, CW, and diode green lasers at 520, 532, 543, and 554 nm, delivering excellent visibility even in sunlight, with 10-50x brighter output than red lasers for high-contrast, long-range use at lower power and cost.

Efficient light-matter interactions outshine IR lasers, providing higher absorption in metals like copper, gold, and aluminum, with smaller spot sizes and reduced HAZ for superior cuts and marks in processing applications.

Our wide range spans DPSS, HeNe, microchip, and diode technologies, from components to OEM integration, with configurable platforms and price points to suit industrial, scientific, and custom needs.

Let RPMC help you find the right green laser today!

Bibliography

[1]	A. J. Silversmith et al., “Green infrared-pumped erbium upconversion laser”, Appl. Phys. Lett. 51, 1977 (1987); https://doi.org/10.1063/1.98316
[2]	F. Tong et al., “551 nm diode-laser-pumped upconversion laser”, Electron. Lett. 25, 1389 (1989); https://doi.org/10.1049/el:19890930
[3]	T. Hebert et al., “Blue and green CW upconversion lasing in Er:YLiF₄”, Appl. Phys. Lett. 57, 1727 (1990); https://doi.org/10.1063/1.104048
[4]	T. J. Whitley et al., “Upconversion pumped green lasing in erbium doped fluorozirconate fibre”, Electron. Lett. 27 (20), 1785 (1991); https://doi.org/10.1049/el:19911110
[5]	E. Kato et al., “Significant progress in II-VI blue-green laser diode lifetime”, Electron. Lett. 34, 282 (1998); https://doi.org/10.1049/el:19980229
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[7]	C. Stolzenburg et al., “Cavity-dumped intracavity-frequency-doubled Yb:YAG thin-disk laser with 100 W average power”, Opt. Lett. 32 (9), 1123 (2007); https://doi.org/10.1364/OL.32.001123
[8]	J.-Y. Kim et al., “Highly efficient green VECSEL with intra-cavity diamond heat spreader”, Electron. Lett. 43 (2), 105 (2007); https://doi.org/10.1049/el:20072787
[9]	O. B. Jensen et al., “1.5 W green light generation by single-pass second harmonic generation of a single-frequency tapered diode laser”, Opt. Express 17 (8), 6532 (2009); https://doi.org/10.1364/OE.17.006532
[10]	T. Miyoshi et al., “510–515 nm InGaN-based green laser diodes on c-plane GaN substrate”, Appl. Phys. Express 2, 062201 (2009); https://doi.org/10.1143/APEX.2.062201
[11]	H. Ohta et al., “Future of group-III nitride semiconductor green laser diodes”, J. Opt. Soc. Am. B 27 (11), B45 (2010); https://doi.org/10.1364/JOSAB.27.000B45
[12]	T. Meier et al., “Continuous-wave single-frequency 532 nm laser source emitting 130 W into the fundamental transversal mode”, Opt. Lett. 35 (22), 3742 (2010); https://doi.org/10.1364/OL.35.003742
[13]	R. Cieslak and W. A. Clarkson, “Internal resonantly enhanced frequency doubling of continuous-wave fiber lasers”, Opt. Lett. 36 (10), 1896 (2011); https://doi.org/10.1364/OL.36.001896
[14]	R. Bhandari and T. Taira, “>6 MW peak power at 532 nm from passively Q-switched Nd:YAG/Cr⁴⁺:YAG microchip laser”, Opt. Express 19 (20), 19135 (2011); https://doi.org/10.1364/OE.19.019135
[15]	H. Chi et al., “Demonstration of a kilowatt average power, 1 J, green laser”, Opt. Lett. 45 (24), 6803 (2020); https://doi.org/10.1364/OL.412975

(Suggest additional literature!)

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Green Lasers

Types of Green Lasers

Applications

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Suppliers

Bibliography

Questions and Comments from Users