Prof. Ralph Jimenez Profile

Prof. Ralph Jimenez

at JILA

SPIE Involvement:

Conference Program Committee | Author

Proceedings Article | 16 March 2023 Presentation

Using time-energy entangled photons to probe biological samples (Conference Presentation)

Charles Camp, Daniel Lum, Michael Mazurek, Alexander Mikhaylov, Kristen Parzuchowski, Ryan Wilson, Ralph Jimenez, Thomas Gerrits, Martin Stevens, Marcus Cicerone

Proceedings Volume PC12393, PC123930B (2023) https://doi.org/10.1117/12.2649192

KEYWORDS: Photons, Imaging spectroscopy, Quantum optics, Tissue optics, Spectroscopy, Biomedical optics, Absorption

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Proceedings Article | 28 February 2020 Presentation + Paper

A comprehensive experimental system for measuring molecular two-photon absorption using an ultrafast entangled photon pair excitation source

Alexander Mikhaylov, Kristen Parzuchowski, Michael Mazurek, Daniel Lum, Thomas Gerrits, Charles Camp, Martin Stevens, Ralph Jimenez

Proceedings Volume 11295, 112950Q (2020) https://doi.org/10.1117/12.2541888

KEYWORDS: Absorption, Transmittance, Interferometers, Time metrology, Ultrafast phenomena

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Proceedings Article | 24 October 2012 Paper

Real-time analysis of multi-laser-beam fluorescence for timed control of laser tweezers in a microfluidic cell-sorting device

Lloyd Davis, Jennifer Lubbeck, Kevin Dean, Amy Palmer, Ralph Jimenez

Proceedings Volume 8412, 84120F (2012) https://doi.org/10.1117/12.2001362

KEYWORDS: Luminescence, Microfluidics, Mirrors, Bragg cells, Control systems, Fluorescent proteins, Optical tweezers, Microscopes, Modulation, LabVIEW

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We have developed a microfluidic cell sorter for mammalian cells expressing intrinsic fluorescent proteins that enables selection of cells with proteins that have enhanced photophysical properties, such as reduced fluorescence photobleaching and/or reversible dark state conversion. Previous ensemble imaging studies have used an acousto-optic modulator (AOM) to provide millisecond pulsed laser illumination for in vivo assays that distinguish reversible darkstate conversion from irreversible photobleaching. However, in the sorter, cells are hydrodynamically focused into a stream, which flows through a series of 4 or 8 line-focused, continuous, 532 nm laser beams, such that each cell experiences a similar millisecond modulated excitation. The amplitude and timing of the fluorescence response from each of the beams are measured by a red-sensitive photomultiplier and analyzed in real time to separately determine initial fluorescence brightness and photobleaching characteristics. In addition, each cell’s flow speed is found from its time of passage through the beams, and if the analysis results are within adjustable limits, a 1064 nm optical trap beam is switched on and moved along an intersecting trajectory at a matching speed, so that the cell becomes deflected by the optical gradient forces towards another exit channel of the microfluidic device. The optical sorting of cells is similar to that demonstrated by others, except that the motion of the trap beam is achieved using a piezo mirror under computer control, rather than an AOM; also, rather than a single-beam brightness measure using a hardwired circuit, a more complex multi-beam analysis is performed in software using the Real-Time module of LabView (National Instruments) on a separate computer to achieve deterministic timing and low latency. The software displays updated statistics of the sort, obtained by counting cells that pass through an extra laser beam in the exit channel. A mixture of cells expressing different proteins was resolved to select those with slowest photobleaching. Cells collected from the instrument were viable and could reproduce.

Proceedings Article | 11 February 2011 Paper

3D optical trapping calibration and optical micromanipulation using 808-nm diode-laser bar

Mariana Potcoava, Leo Krzewina, Erich Hoover, Myung Kim, Jeff Squier, David W. Marr, Ralph Jimenez

Proceedings Volume 7904, 79040A (2011) https://doi.org/10.1117/12.876010

KEYWORDS: Particles, Optical tweezers, Calibration, Semiconductor lasers, Holograms, Digital holography, Microscopes, Optical calibration, CMOS sensors, Holography

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Proceedings Article | 11 February 2011 Paper

Dynamics of optically trapped red blood cells by phase contrast microscopy

Mariana Potcoava, Erich Hoover, Kevin Roth, Gianna Riccota, Jeff Squier, Ralph Jimenez, David W. Marr

Proceedings Volume 7902, 79020V (2011) https://doi.org/10.1117/12.876032

KEYWORDS: Optical tweezers, Phase contrast, Microfluidics, Blood, Microscopes, Semiconductor lasers, Particles, Argon, Microscopy, Calibration

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SPIE Journal Paper | 1 July 2010 Open Access

Cell deformation cytometry using diode-bar optical stretchers

Ihab Sraj, Charles Eggleton, Ralph Jimenez, Erich Hoover, Jeffrey Squier, Justin Chichester, David Marr

JBO, Vol. 15, Issue 04, 047010, (July 2010) https://doi.org/10.1117/12.10.1117/1.3470124

KEYWORDS: Microfluidics, Semiconductor lasers, Optical tweezers, Biomedical optics, Diodes, Video, Spherical lenses, Geometrical optics, Optical simulations, Integrated optics

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Proceedings Article | 19 June 2003 Paper

Photon echo spectroscopy as a probe of dynamics in the immune system

Ralph Jimenez, Floyd Romesberg

Proceedings Volume 4978, (2003) https://doi.org/10.1117/12.478604

KEYWORDS: Proteins, Silver, Chromophores, Data modeling, Spectroscopy, Absorption, Molecules, Crystals, Femtosecond phenomena, Chemical species

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Proceedings Article | 21 October 1999 Paper

Ultrafast movies of atomic motion with femtosecond laser-based x rays

Craig Siders, Andrea Cavalleri, Klaus Sokolowski-Tinten, Ting Guo, Csaba Toth, Ralph Jimenez, Christoph Rose-Petruck, Martin Kammler, Michael Horn-von-Hoegen, Dietrich von der Linde, Kent Wilson, Christopher Barty

Proceedings Volume 3776, (1999) https://doi.org/10.1117/12.366680

KEYWORDS: Ultrafast phenomena, X-rays, Crystals, X-ray diffraction, Picosecond phenomena, Silicon, Germanium, Diffraction, Femtosecond phenomena, Gallium arsenide

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Proceedings Article | 14 October 1997 Paper

Picosecond-milliangstrom resolution dynamics by ultrafast x-ray diffraction

Ting Guo, Christoph Rose-Petruck, Ralph Jimenez, Ferenc Raksi, Jeffrey Squier, Barry Walker, Kent Wilson, Christopher Barty

Proceedings Volume 3157, (1997) https://doi.org/10.1117/12.283987

KEYWORDS: Diffraction, X-rays, X-ray diffraction, Crystals, Ultrafast phenomena, X-ray sources, Picosecond phenomena, Copper, Gallium arsenide, Crystallography

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Showing 5 of 9 publications

Conference Committee Involvement (2)

Quantum Effects and Measurement Techniques in Biology and Biophotonics

25 January 2025 | San Francisco, California, United States

Quantum Effects and Measurement Techniques in Biology and Biophotonics

27 January 2024 | San Francisco, California, United States

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