About the Jimenez Group

Research Areas

  • Our group is actively engaged at the interface of quantum optics with physical chemistry. In this research, we manipulate the properties of light at the single photon or few photon level.  By employing “quantum engineered” light for spectroscopy, we aim to harness the remarkable quantum mechanical properties such as entanglement, superposition, and coherence in order to increase the sensitivity and information content of spectroscopy. We are particularly interested in “real world” measurements on complex molecular and nano-materials systems in room temperature liquids, thin films, or…

  • Since the isolation of the first naturally fluorescing protein from jelly fish in the 1960s, fluorescent proteins (FPs) have become integral to a wide range of biological/medical applications, allowing visualization of biomolecules and processes in living cells and tissues to a much greater degree than was previously possible. Extensive molecular engineering of naturally occurring FPs has led to several families of recombinant proteins tailored to specific biophysical and imaging purposes. Fine-tuning of the activation and multimerization properties of FPs has helped to alleviate some…

Research Interests

Ralph’s interests are in experimental studies of dynamics in complex molecular systems. Over the years, he has worked on a wide range of areas where ultrafast spectroscopy is useful such as femtosecond dynamics of liquids, energy transfer in photosynthetic systems, protein-ligand interactions in antibodies, chromophore dynamics of fluorescent proteins. As part of his research, he has developed a number of optical and microfluidic technologies to advance experimental capabilities in liquid-phase chemical dynamics using time-resolved optical or laser-based x-ray techniques. Most recently he has been exploring applications of quantum optics to molecular spectroscopy.

In general, our research falls into two categories: Quantum Spectroscopy and Fluorescent Proteins.

Stories About Our Research

  • An artistic depiction of the hot band absorption process in the LDS798 molecule. 

    The Prime Suspect: Hot Band Absorption

    The hunt was afoot within the laboratory of JILA and NIST Fellow Ralph Jimenez as his team continued to unravel the mystery of entangled two-photon absorption. Entangled photons are pairs of light particles whose quantum states are not…
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  • Photo of 2-Photon Absorption signal

    The Case of the Missing Signal

    Most researchers would agree that it is much easier to write a paper about an observed effect than a paper proving the nonexistence of the effect when it is not observed. NIST JILA Fellow Ralph Jimenez found this to be the case…
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  • The Jimenez Lab has built a flow cytometry system that quickly sorts fluorescing cells from non-fluorescing ones.

    Sorting the Glow from the Flow

    How do you find a single cell in a sea of thousands? You make it glow. Adding fluorescence helps track movement and changes in small things like cells, DNA, and bacteria. In a library of millions of cells or bacteria, flow cytometry…
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Research Highlights

  • An artistic depiction of the hot band absorption process in the LDS798 molecule. 

    The Prime Suspect: Hot Band Absorption

    The hunt was afoot within the laboratory of JILA and NIST Fellow Ralph Jimenez as his team continued to unravel the mystery of entangled two-photon absorption. Entangled photons are pairs of light particles whose quantum states are not…
    Read More

In the Spotlight

The group photo taken at the Quantum Light Conference hosted by JILA in July 2024
: JILA Hosts the Inaugural Workshop on Quantum Light Generation, Detection, and Applications

JILA, a joint institute of the University of Colorado Boulder and the National Institute of Standards and Technology (NIST) hosted its inaugural workshop on recent technological and research advancements in quantum light from July 17 to 19, 2024. The conference was sponsored by the National Science Foundation (NSF)-funded JILA Physics Frontier Center (PFC), the CUbit Quantum Initiative, and laser company Toptica. 

The event invited speakers from various prestigious institutions, including Texas A&M University, the National Autonomous University of Mexico, Columbia University, Wake Forest University, Livermore National Lab, the University of Illinois Urbana-Champaign, Caltech, Oak Ridge National Lab, Cornell University, William & Mary, University College London, the University of Oregon, the University of Toronto, and the University of Virginia, along with multiple representatives from NIST.


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Connor Thomas, an undergraduate researcher in JILA and NIST Fellow Ralph Jimenez's lab, discusses his time in JILA
: Humans of JILA-Connor Thomas

For some physics and math undergraduates, JILA has become a place to learn cutting-edge research while belonging to a community. That's what undergraduate Connor Thomas experienced. Though Thomas is graduating with a bachelor's in biochemistry and transitioning to a graduate program at MIT, he's been grateful for his time at JILA. "JILA has been a pretty fantastic community for me," Thomas said. "In particular, my lab has been great. They were really constant through COVID. I am definitely going to miss all of that."


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Ralph Jimenez poster.
: Ralph Jimenez Receives Arthur S. Flemming Award for Outstanding Public Service

JILA Fellow and NIST Physicist Ralph Jimenez received the 2017 Arthur S. Flemming Award for outstanding public service as a Federal employee. Jimenez was one of 12 honorees across all parts of the Federal government to receive the Flemming Award this cycle. Jimenez was a winner in the Applied Science and Engineering category for his pioneering research on combining microfluidics, ultrafast lasers, biochemistry and molecular biology to dramatically accelerate the creation and characterization of specialized biomolecules to serve as sensors within living cells.


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Ralph Jimenez photograph.
: Ralph Jimenez Awarded Department of Commerce Bronze Medal

Ralph Jimenez received a Department of Commerce Bronze Medal for Superior Federal Service at a ceremony held in mid-December 2016. The Medal is the highest honor presented by the National Institute of Standards and Technology (NIST). Under Secretary of Commerce for Standards and Technology and NIST Director Willie E. May presided over the awards ceremony, which was held concurrently at NIST's Gaithersburg, Maryland, and Boulder, Colorado, campuses.


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JILA Address

We are located at JILA: A joint institute of NIST and the University of Colorado Boulder.

Map | JILA Phone: 303-492-7789 | Address: 440 UCB, Boulder, CO 80309