Conveners
DAMOPC Poster Session & Student Poster Competition Finals (26) | Session d'affiches DPAMPC et finales du concours d'affiches étudiantes (26)
- Karl-Peter Marzlin (St. Francis Xavier University)
We present a successful combination of stimulated Raman spectroscopy (SRS) and surface-enhanced Raman scattering (SERS) using low-power cw laser sources and gold/silica nano-particles with embedded reporter molecules. We demonstrate that cw surface-enhanced stimulated Raman spectroscopy (cwSESRS) can be used to detect a Raman signal in samples with pico-molar or low nano-molar concentrations...
To improve our nuclear beta decay asymmetry experiment (which presently has the best percentage accuracy ever achieved (0.35%) [B. Fenker et al. Phys. Rev. Lett. 120 062502 (2018)]), we are trying to improve the vector polarization of our laser-cooled atoms from our present 99.1 $\pm$ 0.1% [B. Fenker et al. New J. Phys 18 073028 (2016)]. We cycle on and off a MOT, and optically pump $^{37}$K...
The Cooler Penning Trap (CPET) at TRIUMF’s Ion Trap for Atomic and Nuclear science (TITAN) facility was developed with a goal to further enhance the precision capabilities of TITAN’s mass measurement Penning trap (MPET) for short-lived radioactive isotopes. The sub-ppb precision of the MPET can be further increased by an order of magnitude or more by using highly charged ions extracted from...
Interacting fermions with odd orbital exchange parities are of long-standing interest, but has also proven to be challenging to explore both in materials and with ultracold gases. A p-wave Feshbach resonance is known for several alkali gases, but has been associated with strong loss due to recombination. In contrast to broad s-wave resonances, a high closed-channel fraction of the Feshbach...
Generating and sorting spatial modes of light is a recurring obstacle to using multiple transverse modes for both classical and quantum free-space optical communication. The Hermite-Gaussian (HG) modes provide a complete propagation-invariant set of basis states, but they cannot be transformed or sorted with common optical elements. Current implementations of free-space mode sorting thus...
Le dioxyde de vanadium (VO2 ) est un matériau thermochrome intéressant de la famille des oxydes de métaux de transition ("OMT" ). Il est caractérisé par une température de transition (Tt = 68 °C) réversible. Parmi les "OMT" , le VO2 est celui dont la température de transition (Tt) est la plus proche de la température ambiante. C’est un semi-conducteur en dessous de cette température et...
We initiate unidirectional rotation of chiral molecules with an optical centrifuge and detect their spatial orientation by means of Coulomb explosion imaging. We show that the centrifuge-induced orientation of one of the molecular axes in the laboratory frame depends on the relationship between the chiral handedness of the enantiomer and the direction of the laser-induced molecular rotation....
Using simulations of Molecular Dynamics, we investigated the role of surfactant molecules to be used as agents to capture molecules on solid surfaces, either to remove alkane molecules from a graphite surface or to absorb CO2 in a zeolite. Removal of alkanes from graphite plates simulations on three different surfactants, Cocamidopropyl betaine (CAPB), ...
We propose a method to separate enantiomers using parity violation in the Casimir–Polder potential between chiral mirrors and chiral molecules. The proposed setup involves a molecular beam composed of chiral molecules passing through a planar cavity consisting of two chiral mirrors. Enantiomers of opposite handedness are deflected differently due to a chiral dependence of the Casimir–Polder...
We observe the satisfaction of the sum rule for the conductivity of neutral fermions in an optical lattice subject to weak harmonic confinement. We measure the conductivity spectrum of the atoms through observations of the global current response to a perturbative applied force, using a quantum gas microscope. The spectrum is measured up to frequencies sufficient to characterize intraband...
We study the transport of spin within a weakly-interacting gas of $^{87}$Rb atoms above quantum degeneracy. Spin transport can be modified by tuning coherent spin-rotating interactions with a small effective magnetic field that varies the local Larmor precession. Previously, we have shown that specific linear effective magnetic fields stabilize spin domains [1]. Further manipulation of the...
Improved measurements of the electron electric dipole moment (eEDM) will strongly constrain the parameter space of new physics theories. Over the last decade, polar molecules have become established as the most promising systems for eEDM searches, due to the large internal electric fields experienced by an eEDM in these molecules. The sensitivity of eEDM searches is determined by the coherence...
An optical centrifuge is a tool for controlling coherent molecular rotation with an intense laser field. It is a linearly polarized pulse which starts by rotating slowly and accelerates up to $\sim$10 THz over $\sim$100 ps. Whether a molecule will follow it is determined by comparing the molecule’s moment of inertia to the anisotropic polarizability of the molecule. Several light diatomic and...
Vacuum measurement plays a central role in a wide range of scientific and industrial applications including residual gas analysis, semi-conductor device manufacture, and atmospheric modeling. Remarkably, no primary pressure standard existed for the high (HV) and ultra-high vacuum (UHV) regime (below 10−7 Pa) until recently. In 2018, a UBC and BCIT collaboration succeeded in producing the...
The goal of my project is to develop a nano-optical sensor platform that can detect invasive fish species in the Great Lakes at the streamside. This is a collaboration between Dr. Rangan (Physics), Dr. Heath (GLIER), Dr. Pitcher (GLIER), and Dr. Mittler (Western University). I am doing preliminary experiments and simulations that can establish proof of principle so that the collaboration can...
Since the first demonstration of the vacuum by Torricelli (circa 1643), vacuum measurement and technology have been applied to scientific research and industrial technologies including the processing of semiconductors and the study of the upper atmosphere. However, until now, there has never been a primary pressure standard for the high-vacuum and ultra-high vacuum (UHV), P<10−9 Torr, and...
In a linear Paul ion-trap, the structural transition from a 1-D linear chain of ions to a 2-D zigzag structure, known as the linear-zigzag transition, is a well-known behavior for crystals of laser cooled, trapped ions. Here we present the first studies of the linear-zigzag transition at ultracold temperatures following cooling to near the ground-state of motion. We characterize the transition...
The TITAN facility at TRIUMF performs mass measurements of rare isotopes, e.g. to test the standard model. Charge breeding the radionuclides can increase the attainable measurement precision; however, it may increase the ions’ energy spread, thereby negatively impacting the mass measurement. To leverage the full benefits of Penning trap mass spectrometry with highly charged ions we are...
Ultra-cold atomic ensembles have enabled experimental studies of few and many-body quantum phenomena including topological insulators, many-body pairing phenomena, and superfluidity. The use of ultra-cold molecular ensembles is expected to provide access to even richer phenomena than atoms due to their complex internal structure. Cold molecules are also key to studying and understanding...
Reactive and inelastic collisions of ultra-cold molecules has generally been observed to follow a universal rate law described by the quantum Langevin model. The salient feature of this law is an independence of the reaction probability from the short-range physics of the interaction. We report on reactive and inelastic collisions of $^6$Li$_2$ dimers in several ro-vibrational states of the...
The Antihydrogen Laser Physics Apparatus (ALPHA) Collaboration seeks to measure properties of antihydrogen and compare them to its matter counterpart, hydrogen, to perform precision tests of symmetries between matter and antimatter. Comparisons of hyperfine transition frequencies in positronic ground state antihydrogen with hydrogen provide an opportunity to test fundamental symmetries such as...
For decades, improved theory and experiment of the $n$=2 $^3$P fine structure of helium have allowed for increasingly precise tests of quantum electrodynamics, determinations of the fine-structure constant $\alpha$, and limitations on possible beyond-the-standard-model physics. Here we use the new frequency-offset separated-oscillatory-fields technique to measure the 2$^3$P$_2$$\to$2$^3$P$_1$...
We have measured the Stark shift of the 5s$\rightarrow$6s transition in rubidium using two-photon spectroscopy. The Rb atoms are held in a magneto-optical trap (MOT) at the center of two optically-transparent field plates providing unhindered optical access for the MOT beams. The Stark shift was determined for electric fields from 0.350 kV/cm to 5.249 kV/cm. The 993 nm spectroscopy laser was...
Dynamical backaction has proven to be a versatile tool in cavity optomechanics, allowing for precise manipulation of a mechanical resonator's motion using confined optical photons. In my talk, I will present measurements of a silicon whispering-gallery-mode optomechanical cavity where backaction originates from opposing radiation-pressure and photothermal forces, with the former dictating the...
The behaviour of fast rotating molecules immersed in superfluid helium is studied. More specifically, the system of interest is carbon disulfide “superrotors” inside helium nanodroplets. Droplets ideally capture a single carbon disulfide molecule and are then exposed to two laser beams. The first beam, a laser pulse whose linear polarization undergoes accelerated rotation around the direction...
Optical tweezing is a well-known phenomenon for trapping or manipulating dielectric and metallic nanoparticles. The application of metallic nanoparticles in sensing has attracted much attention due to their unique optical and chemical properties. We manufactured a unique plasmonic structure on the surface of a nanoprobe. The nanoprobe was a tapered fiber, which was developed using a dynamic...
Magnesium and sulphur are the 9th and 10th most abundant elements in our galaxy, and a compound in solid form (niningerite) has been found in meteors. Its gas-phase compounds are therefore candidates for detection in stellar atmospheres, as have been the magnesium-bearing compounds MgNC and MgCN. The simplest combination of these elements, MgS, is a gas-phase radical that until recently had...
Transitions of the gas-phase iron hydride molecule are observed in the spectrum of the sun and of some cooler stars. It has a strong magnetic response, and the Zeeman splitting of individual rotational lines is used to determine the strength of the magnetic field produced by the stars in which its signature is seen. Its spectrum is complicated by the high spin and angular momentum of its...
