Laser Physics
In a new paper published in the Journal of Physical Chemistry Letters, Jimenez and his team report a new experimental setup to search for the cause of a mysterious fluorescent signal that appears to be from entangled photon excitation. The results of their new experiments suggested that hot-band absorption (HBA) by the subject molecules, could be the potential culprit for this mysterious fluorescent signal, making it the prime suspect.
Physicists develop some of the most cutting-edge technologies, including new types of lasers, microscopes, and telescopes. Using lasers, physicists can learn more about quantum interactions in materials and molecules by taking snapshots of the fastest processes, and many other things. While lasers have been used for decades, their applications in technology continue to evolve. One such application is to generate and control x-ray laser light sources, which produce much shorter wavelengths than visible light. This is important because progress in developing x-ray lasers with practical applications had essentially stalled for over 50 years. Fortunately, researchers are beginning to change this by using new approaches. In a paper published in Science Advances, a JILA team, including JILA Fellows Margaret Murnane, and Henry Kapteyn, manipulated laser beam shapes to better control properties of x-ray light.
JILA Fellow Margaret Murnane has been awarded an Honorary Doctorate from the University of Limerick this year - her 6th Honorary Doctorate.
Gravimetry, or the measurement of the strength of a gravitational field (or gravitational acceleration), has been of great interest to physicists since the 1600s. One of the most precise ways to measure gravitational acceleration is to use an atom interferometer. There are many different types of atom interferometers but so far all operate using uncorrelated atoms that are not entangled. To build the best one allowed in nature, it requires harnessing the power of quantum entanglement. However, making a quantum interferometer with entangled atoms is challenging. JILA Fellows Ana Maria Rey and James K. Thompson have published a paper in Physical Review Letters that discusses a new protocol that could make entangled quantum interferometers easier to produce and use.
Congratulations to JILA Fellow Dana Anderson for winning the 2021 Willis E Lamb award for Laser Science and Quantum Optics.
Breath analysis has been fast progressing in recent years and is continuing to gain more and more research interest. It is, however, experimentally challenging due to the extremely low concentrations of molecules present in each breath, limited number of detectable molecular species, and the long data-analysis time required. Now, a JILA-based collaboration between the labs of NIST Fellows Jun Ye and David Nesbitt has resulted in a more robust and precise breath-testing apparatus. In combining a special type of laser with a mirrored cavity, the team of researchers was able to precisely measure four molecules in human breath at unprecedented sensitivity levels, with the promise of measuring many more types of molecules.
Two new papers from the Murnane and Kapteyn group are changing the way heat transport is viewed on a nanoscale, and explain the group’s surprising finding that nanoscale heat transport can be far more efficient than originally thought. One of these papers, published in the Proceedings of the National Academy of Sciences (PNAS), explains heat transport for the tiniest of hotspots, with sizes <100 nm. The other, published in American Chemical Society Nano (ACS Nano), presents a theory that is applicable to larger arrays of hotspots. Both papers postulate theories that can fully explain the surprising data collected by the team of researchers, showing that heat transport on scale lengths relevant to a wide range of nanotechnologies is more efficient than originally thought.
The National Science Foundation has renewed for five years and more than $22 million the cutting-edge Science and Technology Center on Real-Time Functional Imaging (STROBE). STROBE is developing the Microscopes of Tomorrow, and is a partnership between six institutions –– University of Colorado Boulder, UCLA, UC Berkeley, Florida International University, Fort Lewis College, and UC Irvine.
Atomic clocks have been heavily studied by physicists for decades. The way these clocks work is by having atoms, such as rubidium or cesium, that are "ticking" (that is, oscillating) between two quantum states. As such, atomic clocks are extremely precise, but can be fragile to shaking or other perturbations, like temperature fluctuations. Additionally, these clocks need a special laser to probe the clock. Both factors can make atomic clocks imprecise, difficult to study, and expensive to make. A team of physicists are proposing a new type of laser that could change the future path of atomic clocks. In this team, JILA Fellow Murray Holland and Research Associate Simon Jäger theorized a new type of laser system in a paper recently published in Physical Review Letters.
For laser science, one major goal is to achieve full control over the spatial, temporal and polarization properties of light, and to learn how to precisely manipulate these properties. A property of light is called the Orbital Angular Momentum (OAM), that depends on the spatial distribution of the phase (or crests) of a doughnut-shaped light beam. More recently, a new variant of OAM was discovered - called the spatial-temporal OAM (ST-OAM), with much more elusive properties, since the phase/crests of light evolve both temporally and spatially. In a collaboration led by senior scientist Dr. Chen-Ting Liao, working with graduate student Guan Gui and Nathan Brooks and JILA Fellows Margaret Murnane and Henry Kapteyn, the team explored how such beams change after propagating through nonlinear crystals that can change their color. The team published theri results in Nature Photonics.