Laser-Cooled Atoms Group

Creighton UniversityDepartment of Physics

Jonathan P. Wrubel, Ph.D. (Principal Investigator)

This is the research group page of the Laser-Cooled Atoms Group at Creighton University led by Dr. Jonathan Wrubel. Our group is building an experiment to probe quantum physics in a Bose-Einstein condensate of 41K (potassium-41).  This fascinating state of matter is made by using lasers to cool gas atoms down to temperature below a millionth of a degree above absolute zero.  This novel state allows us to study quantum magnetism.

Laser-cooled atoms lab at Creighton University


Masters Research Fellowship in Potassium Bose-Einstein Condensation

The Laser-Cooled Atoms Group at Creighton University has an open fellowship position for a student interested in pursuing research in experimental ultracold atom physics and Bose-Einstein condensation. The fellowship includes full tuition remission and stipend for 2 years.

Students will have an opportunity to work in a unique experiment using lasers to cool a gas of potassium to millionths of a degree above absolute zero. Applicants should have a strong interest in quantum or atomic physics and significant experimental physics research experience. Students will have an opportunity to learn atomic and quantum physics, advanced optics techniques, ultra-high vacuum techniques, and to work with cutting-edge radio-frequency electronics.

Experience in any of these areas is a benefit, but not required. If you are a quick learner, interested in this field, and good in a lab, then this experiment is for you!

False-color image of ultracold potassium-41 atoms in a magneto-optical trap


  • November 2023: We have ultracold atoms successfully loaded in the crossed optical dipole trap!
  • May 2023: Ben DalFavero successfully defended his masters thesis: "Quantum search with interacting bosons on a lattice: Mean-field theory and many-body simulations of quantum walk algorithms"
  • November 2022: Undergraduate Abram Harvey joins the group!
  • October 2022 Commissioning of 1550 nm fiber laser for optical dipole trap
  • August 2022: Undergraduate student Will Conrad joins the group!
  • August 2022: New low-temperature - 12 µK!
  • June 2022: Group members at DAMOP in Orlando, FL
    Laser-cooled atoms group at DAMOP 2022
  • May 2022: First temperature measurements of the 3D MOT
  • February 2022: Dr. Corbyn Mellinger joined the group!
  • October 2021: Our open postdoc position has been filled! We're excited to welcome Corbyn Mellinger from UNL around Februrary 2022.
  • October 2021: Received our dipole trapping laser and new ECDL cooling lasers.
  • June 2021: Completed installation of the imaging objective and radio-frequency resonance coils.
    June 2021 science chamber
  • June 2021: Summer research has started!
  • April 2021: We received major funding through an NSF Nebraska EPSCoR track-1 grant as a part of the EQUATE collaboration.
  • March 2021: Welcome to new masters student David Loos!
  • March 2021: Welcome to new undergraduate researcher Chase!
  • February 2021: Welcome to new undergraduate researchers Jared and Anh!
  • January 2021: Completed design and testing of a custom four-element objective lens for imaging the cold atoms through our vacuum window. The objective has a focal length of 35.6 mm, NA=0.20 and diffraction limited through the vacuum window at 766.7 nm.
    1951 Test Pattern Imaged by the Four-Element Compound Objective Lens
  • December 2020: Congrats to senior researcher Will Tavis on graduation and receiving the William F. Rigge, S.J. Award for Outstanding Research in Physics!
  • October 2020: Welcome new undergradute researchers Mason H., Mason B., and Evan!
  • August 2020: Completed design and testing of computer-controlled RF resonator to induce the RF Feshbach resonance in the potassium atoms.
  • October 2019: We have ultracold atoms! Below is an image of our 3D potassium magneto-optical trap (MOT). The gas of potassium atoms is held in ultrahigh vacuum by six counter-propagating laser beams. Next steps are to measure the temperature and number of the atoms in the MOT.
    3D magneto-optical trap of potassium
  • March 2019: First placement of 3D MOT optics around science chamber. We need to back off to do some fine-tuning of the alignment, but we're getting close to a working 3D MOT.
    3D MOT optics around science chamber
  • January 2019: The last AOM drivers have ben assembled and tested. The 3D MOT optics are 2/3 completed. Looking forward to a working 3D MOT in the next month.
  • June 2018: We had five students attend the American Physical Society Annual Meeting of the Division of Atomic, Molecular, and Optical Physics (DAMOP) in Ft. Lauderdale, FL. M.S. Kellan Kremer (M.S., '19) and undergraduate Catie Ward (B.S., '18) presented posters. From left to right the group is (Gus Hernandez (B.S. '20), Matt Butschek II (M.S. '19), Catie Ward (B.S. '18), Matt Beauchem (B.S. '21), Kellan Kremer (M.S. '19), and Jonathan Wrubel (P.I.).
    2018 DAMOP conference group photo
  • May 2018: The quadrupole coils for the 3D MOT have been completed and tested!
    Quadrupole coils for the 3D Magneto-Optical Trap
  • February 2018: Science chamber has been baked for 1.5 weeks at ~175˚C, and pumped down to 7.6x10-11 Torr. This is 1 part in 10 trillion of atmospheric pressure! Imagine if every atom were the size of a ping-pong ball, then this is like filling Memorial Stadium in Lincoln to the top of the stadium with ping-pong balls 270 times over, and removing all but 1! (approximating the stadium as 180 m long x 130 m wide x 53 m deep)
    2018 Science chamber ion gauge pressure
  • October 2017: Improved 2D MOT of potassium-39!
  • July 2017: First 2D MOT of potassium-39! It needs to be optimized but it's great to have laser-cooled atoms! Next: a 2D MOT of potassium-41.
      2D MOT Fluorescence
  • July 2017: The glass octagonal science cell is installed and baking.
  • April 2017: Catie's large square Helmholtz coils for controlling the experiment magnetic field are tested and working as predicted!
    Helmholtz coils and 1064 nm dipole laser
  • March 2017: Research student Caitlyn Ward receives '17-'18 Clare Boothe Luce Scholarship! Congratulations Catie!
  • August 2016: Rebuilt vacuum system achieved ultra-high vacuum.
  • June 2016: Achieved 2G magnetic field in a resonant coil at 120 MHz!120 MHz RF resonant Helmholtz coil
  • April 2016: Research student Alex Tarter receive a Barry Goldwater Scholarship! Congratulations Alex!
  • March 2016: Research student Caitlyn Ward receives '16-'17 Clare Boothe Luce Scholarship! Congratulations Catie!
  • August 2015: Alex finishes his improved and redisgned potassium oven.Potassium source (open)Potassium source (finished)
  • June 2015: Improved doppler-free absorption spectrum.Potassium Doppler-Free Absorption Spectrum
  • May 2015: M.S. student Nathan Holman successfully defends his thesis: "Progress Towards A Spinor Bose-Einstein Condensate Machine". Nathan is going on to the Ph.D. program at UW Madison to study solid state quantum computing.
  • March 2015: The tapered-amplifier is operational - achieving 1.6 W of light at 767 nm!Tapered Amplifier
  • February 2015: Dr. Wrubel receives a Cottrell College Science Award from the Research Corporation for Science Advancement! The title of the grant is: "Precision Measurement of a Microwave Fano-Feshbach Resonance in Ultracold 41K Atoms"
  • January 2015: The ECDL is locked to the 39K cross-over transition using a Doppler-free saturated absortpion technique.
    Doppler-Free Saturated Absorption Lock
  • January 2014: The external cavity diode laser has its first light!  Nathan Holman (M.S. candidate) is getting it tuned to the correct wavelength.

External-Cavity Diode Laser

Current group members

  • Mason Hayes (class of 2023)
  • Jared Echternach (class of 2023)
  • Mason Borgman (class of 2024)
  • Evan Johnson (class of 2024)
  • Chance Persons (class of 2024)
  • Anh Nguyen (class of 2024)

Past group members

  • Will Tavis (class of 2020) - active magnetic field stabilization
  • Gustavo Hernandez (class of 2020) - 3D MOT coils
  • W. Andy Peterson (M.S. candidate - 2017) - MOT/optical molasses hybrid simulations
  • Joseph Preimesberger (class of 2018) - resonant RF field
  • Caitlyn Ward (class of 2018) - active magnetic field stabilization
  • Alex Tarter (class of 2017) - K41 source, resonant RF field
  • Sruti Prathivadhi-Bhayankaram (class of 2017) - michelson interferometer
  • Shouvik Bhattacharya (M.S. candidate - 2016) - external field cancellation system
  • Nathan Holman (M.S. candidate - 2015) - saturated absorption locking system
  • Lucas Slattery (class of 2015) - source module
  • Ben Schmachtenberger (class of 2015) - laser cavity construction
  • Colin Bertsch (class of 2016) - vacuum equipment testing
  • Steffen Lake (class of 2016) - laser cavity construction

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