Absorption coefficients and scattering losses of TGG, TGP, KTF, FS, and CeF magneto-optical crystals in the visible via cavity ring-down spectroscopy.

We demonstrate a method for determining small absorption coefficients and surface-scattering losses of crystals using cavity ring-down spectroscopy and perform measurements on magneto-optical crystals of terbium gallium garnet (TGG), terbium gallium phosphate (TGP), fused silica (FS), potassium terbium fluoride (KTF), and at 532 and 634 nm. Surface scattering is distinguished from absorption losses by using crystals of different lengths. A figure of merit (FoM) for magneto-optical crystals is defined to evaluate their suitability as intracavity optics in optical cavity applications.

Ultrahigh-density spin-polarized hydrogen isotopes from the photodissociation of hydrogen halides: new applications for laser-ion acceleration, magnetometry, and polarized nuclear fusion.

Recently, our group produced spin-polarized hydrogen (SPH) atoms at densities of at least 10 cm from the photodissociation of hydrogen halide molecules with circularly polarized UV light and measured them via magnetization-quantum beats with a pickup coil. These densities are approximately 7 orders of magnitude higher than those produced using conventional methods, opening up new fields of application, such as ultrafast magnetometry, the production of polarized MeV and GeV particle beams, such as electron beams with intensities approximately 10 higher than current sources, and the study of polarized nuclear fusion, for which the reaction cross sections of D-T and D-He reactions are expected to increase by 50% for fully polarized nuclear spins. We review the production, detection, depolarization mechanisms, and potential applications of high-density SPH.

Spin-Polarized Hydrogen Depolarization Rates at High Hydrogen Halide Pressures: Hyperfine Depolarization via the HY-H Complex.

We measure the magnetization quantum beats of spin-polarized hydrogen (SPH) and spin-polarized deuterium (SPD) with a pickup coil, from the UV photodissociation of HCl, HBr, and DI, in the 5-5000 mbar pressure range. The pressure-dependent depolarization rate is linear at low pressures and reaches a plateau at higher pressures. The high-pressure depolarization rate is observed to be proportional to the halogen nuclear electric quadrupole coupling constant.

Photofragment spin-polarization measurements via magnetization quantum beats: dynamics of DI photodissociation.

We report the electron-spin polarization of D atoms from the photodissociation of DI, at 213 nm and 266 nm, by measuring the magnetization quantum beats of the D atoms with a pick-up coil. We determine that the polarization P is large at both wavelengths (|P|∼ 1), however it is positive at 213 nm, and negative at 266 nm. These results, in both cases, are of opposite sign to calculations, which assume adiabatic dissociation along the AΠ or aΠ states.

Chiral cavity ring down polarimetry: Chirality and magnetometry measurements using signal reversals.

We present the theory and experimental details for chiral-cavity-ring-down polarimetry and magnetometry, based on ring cavities supporting counterpropagating laser beams. The optical-rotation symmetry is broken by the presence of both chiral and Faraday birefringence, giving rise to signal reversals which allow rapid background subtractions. We present the measurement of the specific rotation at 800 nm of vapors of α-pinene, 2-butanol, and α-phellandrene, the measurement of optical rotation of sucrose solutions in a flow cell, the measurement of the Verdet constant of fused silica, and measurements and theoretical treatment of evanescent-wave optical rotation at a prism surface.

Evanescent-wave and ambient chiral sensing by signal-reversing cavity ringdown polarimetry.

Detecting and quantifying chirality is important in fields ranging from analytical and biological chemistry to pharmacology and fundamental physics: it can aid drug design and synthesis, contribute to protein structure determination, and help detect parity violation of the weak force. Recent developments employ microwaves, femtosecond pulses, superchiral light or photoionization to determine chirality, yet the most widely used methods remain the traditional methods of measuring circular dichroism and optical rotation. However, these signals are typically very weak against larger time-dependent backgrounds.