| NSF Org: |
PHY Division Of Physics |
| Recipient: |
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| Initial Amendment Date: | August 13, 2020 |
| Latest Amendment Date: | October 20, 2020 |
| Award Number: | 2018573 |
| Award Instrument: | Standard Grant |
| Program Manager: |
John D. Gillaspy
PHY Division Of Physics MPS Directorate for Mathematical and Physical Sciences |
| Start Date: | August 15, 2020 |
| End Date: | July 31, 2021 (Estimated) |
| Total Intended Award Amount: | $75,650.00 |
| Total Awarded Amount to Date: | $75,650.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
9 OLD CHAPEL RD MIDDLEBURY VT US 05753-6000 (802)443-5000 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
McCardell Bicentennial Hall Middlebury VT US 05753-6113 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | Major Research Instrumentation |
| Primary Program Source: |
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| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.049 |
ABSTRACT
Through a process called laser cooling, dilute gasses of atoms can be slowed and confined, levitating inside ultra-pure steel vacuum chambers. At this point the trapped atoms can be used for next generation applications, like voltage sensing or the simulation of microscopic crystal structure. To pursue such applications, the principal investigators plan to use two different exotic atoms, rubidium and ytterbium, which each require several lasers with vastly different colors to successfully laser cool. These lasers? colors will span from the ultraviolet to infrared regions of the spectrum of light, and levitation can only happen if the energy of the packets of laser light (laser photons) is precisely measured and controlled to within about 0.0001%. This Major Research Instrumentation project funds a pair of high precision devices called wavemeters to measure the photon energies with sufficient accuracy. The two meters, which are designed to function in different parts of the light spectrum, will be networked together with fiber optic cables, enabling both principal investigators to have access to the full measurement range in their physically separate labs. These advanced measurement capabilities will not only generate new scientific results, but also help generate meaningful research projects for undergraduate students at Middlebury College.
The principal investigators (Goodsell and Hess) are planning experiments using, respectively, launched cold rubidium atoms in highly excited Rydberg states and chains of multiple isotopes of trapped cold ytterbium ions. These particles require excitation light between 370 and 1250 nm for transitions that are hard to determine by secondary observation such as absorption spectroscopy. This Major Research Instrumentation project funds a network of Fizeau and Michelson wavelength meters (wavemeters) to make real-time measurements of laser wavelength. To span the entire spectrum required by both research groups, the network will consist of two wavemeters with different wavelength sensitivity ranges and sufficient measurement speed to stabilize lasers with feedback from the wavemeters. The wavemeters will be connected to each PI's research space using fiber optic links and multiplexed fiber switches, therefore allowing the full range of lasers required by each research group to be monitored simultaneously. With this instrumentation, the principal investigators advance two areas of research: observations of Rydberg atoms subject to the spatially-dependent force of a charged wire, which highlight the Stark effect in a quantum regime, and experiments co-trapping ions of different isotopic species in order to study their efficacy as sympathetic coolants for qubit ions.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
The principal investigators Goodsell and Hess conduct experiments using, respectively, launched cold rubidium atoms and chains of trapped cold ytterbium ions. These experiments require excitation light between 370 and 1250 nm for transitions that are hard to determine by secondary observation techniques such as absorption spectroscopy. The funding from this Major Research Instrumentation (MRI) award has led to the purchase of two wavelength meters (wavemeters) coupled by a fiber-optic network spanning their two research spaces. PIs Hess and Goodsell have implemented independent use of the individual wavemeters and are prepared to use the fiber network connecting their labs and wavemeters to distribute stabilized laser light as a shared laboratory resource.
The Fizeau wavelength meter residing in the lab of PI Hess has been utilized as part of a pair of student projects in summer 2021. The projects centered around using the wavemeters as a source of measurement feedback to stabilize the output wavelength of research-grade lasers, some commercially produced and some built by students. The projects demonstrated that it was feasible to use the wavemeter along with some custom designed software to simultaneously stabilize multiple laser sources. The software and hardware built to perform this task will be an important piece of lab infrastructure for further experiments aimed at laser cooling and trapping atomic ions. Moreover, the software could perform the same task in conjunction with the wavemeter in PI Goodsell’s lab, or be distributed more widely through an open source web distribution.
The Fizeau wavelength meter will also be directly used for a senior undergraduate project with PI Hess in the fall of 2021. The student plans to build a high-resolution spectroscopy experiment for ytterbium atoms, for which calibrating the spectroscopy laser’s wavelength with the wavemeter will be crucial. In 2022 and beyond the capability to measure and stabilize multiple laser’s wavelengths with this wavemeter will be necessary for demonstrating laser cooling and trapping of atomic ions in the Hess lab. This experimental apparatus will be used to develop new tools for performing quantum information science research with trapped ions.
PI Goodsell and her students currently use the Michelson wavemeter in conjunction with diode lasers to cool and trap neutral rubidium atoms. Four lasers with precise adjustable frequencies are used in the process of cooling and trapping, and all four are monitored using absorption of light in a sample of warm gas. The cooled and trapped atoms are launched upward, and they pass through two more weak laser beams that the group uses to measure or to excite the atoms in flight. The lasers that provide light for excitation cannot be easily monitored with warm-gas samples. Instead, the group has incorporated measurements using their new Michelson wavemeter. As a preliminary demonstration, the group has used readings from the precise wavemeter to calibrate spectral measurements of the ground states of cold atoms in flight, in the range of 780 nm, free from the effects of velocity-dependent (Doppler) spreading that broaden the spectral peaks of warm atoms. This establishes the process for the next steps of exciting atoms into high-energy (Rydberg) states, which is only possible with the new equipment that will extend measurements into the wavelength range up to 1250 nm. Selective excitation to Rydberg states will allow the group to explore quantum physics for cold atoms attracted and repelled by external electric fields (manifested in Stark effects for Rydberg states) and is a useful foundation for measuring stray fields or patch fields with sensitive Rydberg atoms.
Student researchers in the Hess and Goodsell groups work with a number of key laboratory tools and techniques (e.g. optics, vacuum chambers, and control electronics). Precise wavelength measurements add to that manifold of skills. Overall in the Hess and Goodsell labs, the equipment purchased with this award was already used by 3 students over the 1-year period of the award, with further engagement of at least 3 more students anticipated in the upcoming academic year and more on an ongoing basis. The research investment impacts these students by engaging them more deeply in the scientific process, strengthening their skills and physics content knowledge, and therefore preparing them to think critically and contribute productively in off-campus internships and post-graduate positions.
Last Modified: 11/01/2021
Modified by: Paul W Hess
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