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…

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.

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

  • 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 in…
    Read More

  • 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…
    Read More

  • Thumbnail

    Molecule Movies, Now Filming at NIST

    The actors are molecules. The plot, broken molecular bonds. JILA Fellow Ralph Jimenez and a team of detector experts at the National Institute of Standards and Technology (NIST) are working together to make X-ray movies of a molecular…
    Read More

  • Thumbnail

    The Red Light District

    Far-red fluorescent light emitted from proteins could one day illuminate the inner workings of life. But before that happens, scientists like Fellow Ralph Jimenez must figure out how fluorescent proteins’ light-emitting structures work…
    Read More

  • Thumbnail

    Mutant Chronicles

    Because red fluorescent proteins are important tools for cellular imaging, the Jimenez group is working to improve them to further biophysics research. The group’s quest for a better red-fluorescent protein began with a computer…
    Read More

  • Thumbnail

    Cross-Cultural Spectroscopy

    Graduate student Jennifer Lubbeck (Jimenez Group) spent the summer of 2011 doing research in the Molecular Spectroscopy Laboratory at the RIKEN Institute in Wako, Japan (near Tokyo). Her host's group included 16 postdocs and four…
    Read More

  • Thumbnail

    Stretched Thin

    Fellow Ralph Jimenez is applying his knowledge of lasers, microscopy, and the precise control of tiny amounts of fluids to the development of a battery-powered blood analyzer for use "off-grid" in Third World countries. He is…
    Read More

  • Thumbnail

    Meet the JILA MONSTRs

    Fellows Steve Cundiff and Ralph Jimenez have created two precision optics instruments with a priceless potential for shedding light on condensed-matter and biological physics. Instrument shop staffer Kim Hagen aided and abetted them in…
    Read More

  • Thumbnail

    A Protein Runs Through It

    An excellent way to watch proteins fold is to probe the inside of a microfluidics device with light. This tiny device contains micron-sized three-dimensional (3D) transparent channels that carry small amounts of liquid. Inside the…
    Read More

  • Thumbnail

    Reflection Grisms

    Fellows Ralph Jimenez and Henry Kapteyn and their groups recently helped develop optical technology that will make femtosecond laser experiments much simpler to perform, opening the door to using such lasers in many more laboratories.…
    Read More

  • Thumbnail

    Heme Motions

    Our lives depend on heme. As part of hemoglobin, it carries oxygen to our tissues. As part of cytochrome c, it helps transform the energy in food into the energy-rich molecule ATP (adenosine triphosphate) that powers biochemical…
    Read More

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

  • 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 in…
    Read More

  • 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…
    Read More

  • Thumbnail

    Molecule Movies, Now Filming at NIST

    The actors are molecules. The plot, broken molecular bonds. JILA Fellow Ralph Jimenez and a team of detector experts at the National Institute of Standards and Technology (NIST) are working together to make X-ray movies of a molecular…
    Read More

  • Thumbnail

    The Red Light District

    Far-red fluorescent light emitted from proteins could one day illuminate the inner workings of life. But before that happens, scientists like Fellow Ralph Jimenez must figure out how fluorescent proteins’ light-emitting structures work…
    Read More

  • Thumbnail

    Mutant Chronicles

    Because red fluorescent proteins are important tools for cellular imaging, the Jimenez group is working to improve them to further biophysics research. The group’s quest for a better red-fluorescent protein began with a computer…
    Read More

  • Thumbnail

    Cross-Cultural Spectroscopy

    Graduate student Jennifer Lubbeck (Jimenez Group) spent the summer of 2011 doing research in the Molecular Spectroscopy Laboratory at the RIKEN Institute in Wako, Japan (near Tokyo). Her host's group included 16 postdocs and four…
    Read More

  • Thumbnail

    Stretched Thin

    Fellow Ralph Jimenez is applying his knowledge of lasers, microscopy, and the precise control of tiny amounts of fluids to the development of a battery-powered blood analyzer for use "off-grid" in Third World countries. He is…
    Read More

  • Thumbnail

    Meet the JILA MONSTRs

    Fellows Steve Cundiff and Ralph Jimenez have created two precision optics instruments with a priceless potential for shedding light on condensed-matter and biological physics. Instrument shop staffer Kim Hagen aided and abetted them in…
    Read More

  • Thumbnail

    A Protein Runs Through It

    An excellent way to watch proteins fold is to probe the inside of a microfluidics device with light. This tiny device contains micron-sized three-dimensional (3D) transparent channels that carry small amounts of liquid. Inside the…
    Read More

  • Thumbnail

    Reflection Grisms

    Fellows Ralph Jimenez and Henry Kapteyn and their groups recently helped develop optical technology that will make femtosecond laser experiments much simpler to perform, opening the door to using such lasers in many more laboratories.…
    Read More

  • Thumbnail

    Heme Motions

    Our lives depend on heme. As part of hemoglobin, it carries oxygen to our tissues. As part of cytochrome c, it helps transform the energy in food into the energy-rich molecule ATP (adenosine triphosphate) that powers biochemical…
    Read More

In the Spotlight

Connor Thomas, an undergraduate researcher in JILA and NIST Fellow Ralph Jimenez's lab, discusses his time in JILA
May 10, 2022: 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.
May 30, 2018: 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.
February 03, 2017: 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