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.
4th Year Physics Graduate StudentBachelor of Science in Physics, Michigan State University
My research is focused on the design and implementation of various measurements of cross-sections for entangled two-photon absorption, a process in which entangled photon pairs are used to excite two-photon transitions. Entangled two-photon absorption has shown promise for biological imaging at low excitation intensity, however the magnitude of the “quantum advantage” of the process needs further study.
4th Year Physics Graduate Student
Bachelor of Science in Physics, The College of New Jersey
Upconversion nanoparticles (UCNPs) are luminescent nanoparticles that can absorb two or more photons and emit a single photon of a higher energy. In contrast to two photon absorption which involve virtual intermediate states, UCNPs have real metastable excited states that allow for multiphoton absorption. UCNPs are good candidates for bioimaging due to various advantages such as deep tissue penetration, excellent biostability, low cytotoxicity, and no autofluorescence. Despite UCNP efficiency being far higher than that of two photon absorption, it is still too low for biomedical applications. I will be working on generating and characterizing energy-time entangled photons for optimizing UCNP efficiency for use as a bioimaging tool.
5th year Physical Chemistry Ph.D. Candidate
Integrated Bachelor and Master of Sciences, IISER Mohali, India
Fluorescent biomarkers have revolutionized microscopy and biological research, yet the complexity of light matter interactions in such applications need detailed understanding through spectroscopic analysis. Trained as a Physical Chemist, I am investigating the photophysical properties of Fluorescent Proteins and developing technologies to generate brighter Fluorescent Proteins. I have developed high-throughput optically-integrated microfluidcs assays to direct the evolution of Red Fluorescent proteins to higher fluorescence lifetime values. I am currently studying the implications of higher fluorescence lifetimes on the pathways of energy decay in Fluorescent Proteins - namely, the radiative and the non-radiative rate constants of decay. Aside from this, I am also investigating the dark state conversion properties of fluorescent proteins and I am studiying the impacts of the changes in lifetime on parameters such as single molecule blinking.
Annika is a sophomore at CU-Boulder double majoring in Music and Chemistry. Annika is currently assisting in the project that is associated with the spectroscopic analysis of Fluorescent Proteins. Apart from her skills in Clarinet and Chemistry - she is an accomplished art enthusiast. Annika was also recently awarded the Bob abd Dickie Lacher Scholarship from CU's Chemistry department.
Connor is a junior majoring in Biochemistry at CU Boulder. His current role involves photophysical characterization of fluorescent proteins and active assistance in the directed evolution of FPs using microfluidics. Connor is also participating in developing image analysis algorithms using programming to quantify single molecule fluorescence blinking kinetics in FPs. Connor is currently funded by the BSI Initiative at CU Boulder.
Connor has a passionate outlook towards marine organisms among other things.
Professional Research Associates
BS (Mechanical Engineering), Ohio State University
MBA, Pepperdine University
Ph.D. (Biochemistry), University of Colorado – Boulder
As a Senior Research Associate at JILA, my work is focused on developing high throughput, analytical instruments to evaluate cyanobacteria and algae for their biofuel/biochemical production potential. These evaluations are performed at the single cell level and are capable of measuring physical properties such as cell size (based on forward scattered light), chlorophyll content, photosynthetic efficiencies (real-time quantum yield measurements) and lipid production (using lipid-specific fluorescence stains). Previous research concentrated on custom-built, microfluidic cytometers that were used to assess the effect of culture conditions upon lipid production in diatoms (Phaeodactylum tricornutum). Previous collaborations with major research labs investigated synergistic properties of mixed algal/cyanobacterial populations. Current research focuses on selection/sorting schemes to assist research in library screens, signal transduction pathway discovery and strain improvement. Work on these projects is rewarding because of the challenging mix of engineering, physical, biological and biochemical sciences.
Ph.D. Cornell University, Biochemistry, Molecular and Cell Biology
B.S. Molecular, Cellular and Developmental Biology, University of Colorado
I have a relatively broad background in the life sciences, from examining photoreceptor proteins in plants, HIV and SIV protein structure/function and DNA replication proteins in yeast to exploring how temperature influences disease susceptibility and microbial community dynamics in Caribbean corals. I have also acted as a scientific consultant in regulatory toxicology issues, as a general bioscience editor and as a laboratory manager. I hope to apply this uniquely diverse skillset towards furthering the efforts of the Jimenez lab.
Lila or Little Lab Counsellor or Little Miss Louisana pays visits to our lab as the official counsellor for our lab members !
She is known to provide for services that include tummy tucks, little licky nibbles and the occasional roll overs.