The temperature on the atomic scale depends on the rate of movement of the atoms. Cooling individual atoms usually boils down to preventing the atoms from moving. But how does one grab a single atom and stop it?
Some atomic cooling techniques are Doppler cooling, Sub–Doppler cooling, and atom evaporation in a Bose-Einstein condensate.
Atomic trapping and cooling are typically used in applications such as:
- time/frequency standards (atomic clocks)
- GPS systems and navigation
- research on fundamental constants
- quantum information (computing and encryption)
- atom interferometry
For laser cooling on atomic resonances (such as Doppler cooling), you need a precise wavelength to match a specific atomic/ion transition, making DFB fiber lasers ideal. You can get this from a laser with a linewidth narrower than the atomic transition.
Higher power lets you cool more atoms simultaneously. No other commercial system provides equally high power at key cooling and trapping wavelengths as the Koheras HARMONIK, and with pristine beam quality.
Our offers for trapping and cooling applications
Koheras lasers offer ultra-low noise, narrow linewidth, and high-frequency stability in a rugged fiber format. For trapping and cooling applications, we recommend our Koheras BOOSTIK HP single-frequency laser together with the Koheras HARMONIK frequency converter modules.
The BOOSTIK system has advantages that have made it a daily driver in hundreds of laboratories around the World:
- High power
- Excellent beam quality
- Ultra-low phase noise
- Easy to use and maintenance-free

The BOOSTIK HP laser and HARMONIK frequency converter module come in different wavelength ranges and power levels to suit the many different needs of atomic physics.
Model | Wavelength | Output power | PM | Piezo tuning |
HARMONIK | 775-780 nm | >7 W | Optional | Yes |
Y10 | 1030-1090 nm | 2, 5, 10 or 15W | Optional | Yes |
E15 | 1530-1575 nm | 2, 5 or 10W | Optional | Yes |
C15 | 1530-1575 nm | 2, 5 or 10W | Optional | Yes |
Get wavelength freedom
One of the key advantages of our DFB fiber laser technology is the freedom to choose the operating wavelength. Due to the excellent beam quality, frequency conversion can efficiently bring many important applications within atomic physics within reach of the HARMONIK system.
Frequency conversion examples are shown below.

aeroGUIDE-POWER fiber delivery for high power narrow linewidth light

The aeroGUIDE-POWER is the gold standard of high power single-mode fiber delivery and offers the highest nonlinear threshold of any PM single-mode delivery system on the market.
The systems are equipped with high-power SMA-905 connectors with built-in mode strippers to remove uncoupled light. The aeroGUIDE-POWER is single-mode and can guide light with low loss anywhere in the 500 to 2000 nm range. The fiber is protected by an armored square lock steel cable that can handle daily use and even inter-lab routing through walls.
How have others used Koheras lasers for atomic physics
Trapping and cooling
Barium
- Ultra-low-vibration closed-cycle cryogenic surface-electrode ion trap apparatus by T. Dubielzig, S. Halama, H. Hahn, G. Zarantonello, M. Niemann, A. Bautista-Salvador, C. Ospelkaus published in Review of Scientific Instruments, 2021.
- A frequency quintupled laser at 308 nm for spectroscopy of intercombination lines in zinc by Maya Büki, David Röser, Simon Stellmer published in Physics Optics, 2021.
- Frequency-quintupled laser at 308 nm for atomic physics applications by Maya Büki, David Röser, and Simon Stellmer published in Applied Optics, 2021.
- Systematic optimization of laser cooling of dysprosium by Florian Mühlbauer, Niels Petersen, Carina Baumgärtner, Lena Maske, Patrick Windpassinger published in Applied Physics B, 2018.
- Hyperfine and optical barium ion qubits by M. R. Dietrich, N. Kurz, T. Noel, G. Shu, and B. B. Blinov published in Physics Review, 2010.
- Magneto-optical trapping of barium by S. De, U. Dammalapati, K. Jungmann, and L. Willmann published in Physics Review, 2009.
- Barium Ions for Quantum Computation by M. R. Dietrich, A. Avril, R. Bowler, N. Kurz, J. S. Salacka, G. Shu, B. B. Blinov published in Atomic Physics, 2009.
- Isotope shifts of 6s5d3D-6s6p1P1 transitions in neutral barium by U. Dammalapati, S. De, K Jungmann, L. Willmann published in The European Physical Journal D, 2009.
Beryllium
- 139 GHz UV phase-locked Raman laser system for thermometry and sideband cooling of 9Be+ ions in a Penning trap by J. Mielke, J. Pick, J. A. Coenders, T. Meiners, M. Niemann, J. M. Cornejo, S. Ulmer, C. Ospelkaus published in Journal of Physics B: Atomic, Molecular and Optical Physics, 2021.
- Ultra-low-vibration closed-cycle cryogenic surface-electrode ion trap apparatus by T. Dubielzig, S. Halama, H. Hahn, G. Zarantonello, M. Niemann, A. Bautista-Salvador, C. Ospelkaus published in Review of Scientific Instruments, 2021.
- Thermometry of 9Be+ ions in a cryogenic Penning trap thesis by Johannes Mielke, Leibniz University Hannover, 2021.
- Cryogenic 9Be+ Penning trap for precision measurements with (anti-)protons by M. Niemann, T. Meiners, J. Mielke, M. J. Borchert, J. M. Cornejo, S. Ulmer, C. Ospelkaus published in Measurement Science and Technology, 2019.
- Control and measurement of a single-ion quantum harmonic oscillator thesis by Katherine Casey McCormick, University of Colorado, 2019.
- Two-qubit microwave quantum logic gate with 9Be+ ions in scalable surface-electrode ion traps thesis by Henning Hahn, Leibniz University Hannover, 2019.
- A Be+ ion trap for H2+ spectroscopy thesis by Johannes Heinrich, Sorbonne University, 2018.
- Setup of a vibration-suppressed cryogenic system for a RF ion trap with minimum micromotion thesis by Lukas Josef Spiess, Max Planck Institute, 2018.
Magnesium
- Thermometry of 9Be+ ions in a cryogenic Penning trap thesis by Johannes Mielke, Leibniz University Hannover, 2021.
- Towards an 27Al+ based optical clock by Khabarova Ksenia, Zalivako Ilia, Semerikov Ilya, Borisenko Alexander, Kolachevsky Nikolay published by IEEE, 2018.
- Laser cooling of externally produced Mg ions in a Penning trap for sympathetic cooling of highly charged ions by Z. Andelkovic, R. Cazan, W. Nörtershäuser, S. Bharadia, D. M. Segal, R. C. Thompson, R. Jöhren, J. Vollbrecht, V. Hannen, M. Vogel published in Physical Review A, 2013.
- A Solid State Laser System for the Cooling of Magnesium Ions by R. Cazan, C. Geppert, W. Nörtershäuser, 2013.
- Towards sympathetic cooling of trapped ions with laser-cooled Mg + ions for mass spectrometry and laser spectroscopy by Radu Cazan, Christopher Geppert, Wilfried Nörtershäuser, Rodolfo Sánchez published in Hyperfine Interactions, 2010.
Rubidium
- Ultranarrow bandwidth Faraday atomic filter approaching natural linewidth based on cold atoms by Wei Zhuang, Yang Zhao, Shaokai Wang, Zhanjun Fang, Fang Fang, Tianchu Li, published in Chinese Optics Letters, 2021.
- Performance of an optical single-sideband laser system for atom interferometry by Clemens Rammeloo, Lingxiao Zhu, Yu-Hung Lien, Kai Bongs, Michael Holynski, published in Journal of the Optical Society of America B, 2020.
- Optical frequency generation using fiber Bragg grating filters for applications in portable quantum sensing by C. D. Macrae, K. Bongs, M. Holynski, published in Atomic Physics, 2020.
- Doppler Compensated Cavity For Atom Interferometry by Rustin Nourshargh, Sam Hedges, Mehdi Langlois, Kai Bongs, Michael Holynski, published in Atomic Physics, 2020.
- Time-scale Generation Methods Based on an Optical Clock by Artem Gribov, Denis Sutyrin, Oleg Berdasov, Sergey Antropov, Gleb Belotelov, Evgeniya Stelmashenko, Aleksei Kostin, Mikhail Gurov, Alexander Malimon, Daria Fedorova, Roman Balaev, Sergey Slyusarev published in IEEE Xplore, 2020.
- Multi-second magnetic coherence in a single domain spinor Bose–Einstein condensate by Silvana Palacios, Simon Coop, Pau Gomez, Thomas Vanderbruggen, Y. Natali Martinez de Escobar, Martijn Jasperse, Morgan W Mitchell, published in New Journal of Physics, 2018.
- Optical frequency standard of continuous wave for fiber communication based on optical comb by Ruiyuan Liu, Ye Li, Cheng Qian, Dawei Li, Jianxiao Leng, Jianye Zhao, published in Optics Communications, 2018.
- Compact and robust laser system for rubidium laser cooling based on the frequency doubling of a fiber bench at 1560 nm by F. Lienhart, S. Boussen, O. Carraz, N. Zahzam, Y. Bidel, A. Bresson published in Applied Physics B, 2007.
- Two-photon photoassociation spectroscopy of heteronuclear YbRb by Frank Münchow, Cristian Bruni, Maximilian Madalinski, Axel Görlitz published in Physical Chemistry Chemical Physics, 2011.
Strontium
- Frequency stabilized ultra-low-noise DFB fiber laser based on intracavity dual mode frequency self-reference mechanism by Kang Ying, Haoyang Pi, Xuan Li, Qing Ye, Haiwen Cai published by SPIE, 2022.
- High-Power, Fiber-Laser-Based Source for Magic-Wavelength Trapping in Neutral-Atom Optical Clocks by William J. Eckner, Aaron W. Young, Nathan Schine, Adam M. Kaufman published in Review of Scientific Instruments, 2021.
- Time-scale Generation Methods Based on an Optical Clock by Artem Gribov, Denis Sutyrin, Oleg Berdasov, Sergey Antropov, Gleb Belotelov, Evgeniya Stelmashenko, Aleksei Kostin, Mikhail Gurov, Alexander Malimon, Daria Fedorova, Roman Balaev, Sergey Slyusarev published by IEEE, 2020.
- Sympathetic cooling in a multi-isotope Sr+ Coulomb crystal by S. Removille, Q. Glorieux, T. Coudreau, L. Guidoni, J.-P. Likforman, S. Guibal in SPIE Photonics Europe. International Society for Optics and Photonics, 2010.
- Trapping and cooling of Sr+ ions: strings and large clouds by S. Removille, R. Dubessy, B. Dubost, Q. Glorieux, T. Coudreau, S. Guibal, J-P Likforman, L. Guidoni published in Journal of Physics B: Atomic, Molecular and Optical Physics, 2009.
Ytterbium
- Efficient sympathetic cooling in mixed barium and ytterbium ion chains by Tomasz P. Sakrejda, Liudmila A. Zhukas, Boris B. Blinov published in Quantum Information Processing volume 20, 2021.
- Active position stabilization of an atomic cloud in a narrow-line magneto-optical trap using a Raspberry Pi by C. Sillusa, T. Franzen, B. Pollklesener, A. Görlitz published in Review of Scientific Instruments, 2021.
- Narrow-linewidth all-solid large-mode-area photonic crystal fiber amplifier by Jakob M. Hauge, Sidsel R. Papior, Jens E. Pedersen, Simon L. Christensen, Magalie Bondu, Thomas T. Alkeskjold, Jesper Lægsgaard by SPIE, 2019.
- Novel Methods in Trapped-Ion Quantum Computing: Single-Photon-Sensitive Time-Resolving Camera, Sympathetic Cooling, and Qutrit thesis by Liudmila Zhukas, University of Washington, 2021.
- Atomic fountain of laser-cooled Yb atoms for precision measurements by Kanhaiya Pandey, K. D. Rathod, Alok K. Singh, Vasant Natarajan published in Physical Review A, 2010.
- Magnetic trapping of Yb in the metastable 3 P2 state by Kanhaiya Pandey, K. D. Rathod, Sambit Bikas Pal, and Vasant Natarajan published in Physical Review A, 2010.
- Fiber-comb-stabilized light source at 556 nm for magneto-optical trapping of ytterbium by Masami Yasuda, Takuya Kohno, Hajime Inaba, Yoshiaki Nakajima, Kazumoto Hosaka, Atsushi Onae, Feng-Lei Hong published in Journal of the Optical Society of America B, 2010.
- High power narrow linewidth laser at 556 nm for magneto-optical trapping of ytterbium by S. Uetake, A. Yamaguchi, S. Kato, Y. Takahashi published in Applied Physics B, 2008.
- Cooling and Trapping of Ytterbium Magneto-Optical Trapping-Direct Loading of Yb Atoms Into a 556 nm MOT by Sambit Pal.
Helium
- A simple 2 W continuous-wave laser system for trapping ultracold metastable helium atoms at the 319.8 nm magic wavelength by R. J. Rengelink, R. P. M. J. W. Notermans, W. Vassen published in Applied Physics B, 2016.
General
- Scheid, Martin, et al. “Continuous-wave Lyman-α generation with solid-state lasers.” Optics express 17.14 (2009): 11274-11280.
- Kolbe, Daniel, et al. “A reliable cw Lyman-α laser source for future cooling of antihydrogen.” Hyperfine Interactions 212.1-3 (2012): 213-220.
- Palacios Álvarez, Silvana. “High-coherence light source for atom trapping and cooling.” (2012).
- Bernon, Simon, et al. “Heterodyne non-demolition measurements on cold atomic samples: towards the preparation of non-classical states for atom interferometry.” New Journal of Physics 13.6 (2011): 065021.
Spectroscopy
- Chanteau, B et al. “Mid-infrared laser phase-locking to a remote near-infrared frequency reference for high-precision molecular spectroscopy” New J. Phys. 15 073003
- Persijn, S., et al. “Quantitative gas measurements using a versatile OPO-based cavity ringdown spectrometer and the comparison with spectroscopic databases” Applied Physics B, Volume 100, Issue 2, pp 383-390
Frequency conversion
- P. Herskind, J. Lindballe, C. Clausen, J. L. Sørensen, and M. Drewsen “Second-harmonic generation of light at 544 and 272 nm from an ytterbium-doped distributed-feedback fiber laser” OPTICS LETTERS / Vol. 32, No. 3 / February 1, 2007
- Uwe Brinkmann “Ytterbium fiber laser is efficiently frequency-quadrupled” Laser Focus World
- Dawson, Jay W., et al. “Multi-watt 589nm fiber laser source.” Lasers and Applications in Science and Engineering. International Society for Optics and Photonics, 2006.
- Markert, Frank, et al. “4W continuous-wave narrow-linewidth tunable solid-state laser source at 546nm by externally frequency doubling a ytterbium-doped single-mode fiber laser system.” Optics express 15.22 (2007): 14476-14481.
- Kolbe, et al. “Triple resonant four-wavemixing boosts the yield of continuous coherent VUV generation.” arXiv preprint arXiv:1203.2121 (2012).
- Stappel, M., et al. “A high power, continuous-wave, single-frequency fiber amplifier at 1091 nm and frequency doubling to 545.5 nm.” Laser Physics 23.7 (2013): 075103.
Other
- Bertoldi, A., et al. “In situ characterization of an optical cavity using atomic light shift” Opt. Lett. 35, 3769 (2010)
- Søgaard S. et al. “Wavelength modulation of fibre lasers – a direct comparison with DFB lasers and extended cavity lasers” OFS 2000, vol. 4185. Venice, Italy, 2000. p. 436-439.
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