Jeremy Bourhill

Ultrahigh cooperativity interactions between magnons and resonant photons in a YIG sphere

Resonant photon modes of a 5-mm-diameter yttrium iron garnet (YIG) sphere loaded in a cylindrical cavity in the 10\char21{}30-GHz frequency range are characterized as a function of applied dc magnetic field at millikelvin temperatures. The photon modes are confined mainly to the sphere and exhibited large mode filling factors in comparison to previous experiments, allowing ultrastrong coupling with the magnon spin-wave resonances. The largest observed coupling between photons and magnons is

Spin bath maser in a cryogenically cooled sapphire whispering gallery mode resonator

2g/2\ensuremath{\pi}=7.11

‘Fast light’ effect in experiments with cryogenic resonators

GHz for a 15.5-GHz mode, corresponding to a cooperativity of

Cavity Magnon Polaritons with Lithium Ferrite and 3D Microwave Resonators at milli-Kelvin Temperatures.

C=1.51\ifmmode\pm\else\textpm\fi{}0.47\ifmmode\times\else\texttimes\fi{}{10}^{7}

Indirect methods to control population distribution in a large spin system

. Complex modifications, beyond a simple multioscillator model, of the photon mode frequencies were observed between 0 and 0.1 T. Between 0.4 and 1 T, degenerate resonant photon modes were observed to interact with magnon spin-wave resonances with different coupling strengths, indicating time-reversal symmetry breaking due to the gyrotropic permeability of YIG. Bare dielectric resonator mode frequencies were determined by detuning magnon modes to significantly higher frequencies with strong magnetic fields. By comparing measured mode frequencies at 7 T with finite element modeling, a bare dielectric permittivity of

Sensitivity characterisation of a parametric transducer for gravitational wave detection through optical spring effect

15.96\ifmmode\pm\else\textpm\fi{}0.02

Precision measurement of a low-loss cylindrical dumbbell-shaped sapphire mechanical oscillator using radiation pressure

of the YIG crystal has been determined at about 20 mK.

Rigorous analysis of highly tunable cylindrical transverse magnetic mode re-entrant cavities

We report the observation of a mechanism of maser generation in an ensemble of intercoupled, inhomogeneously broadened two-level systems, enhanced by high quality factor electromagnetic cavity modes. In this form of population inversion, an inseparable quantum system leads to cavity-enhanced stimulated emission arising from interactions within an ensemble of two-level systems, as opposed to a traditional ensemble of noninteracting identical three-level systems. The effect is observed in a cryogenically cooled whispering gallery mode sapphire resonator containing dilute Fe

The ORGAN Experiment: An axion haloscope above 15 GHz

{}^{3+}

Collective behavior of Cr3+ ions in ruby revealed by whispering gallery modes

impurity ions. These ions exhibit strong spin-lattice interaction, leading to both electron spin resonance broadening and phonon mediated spin-spin coupling. The maser effect is due to a