We present and analyze four frequency measurements designed to characterize the performance of an optical frequency reference based on spectral hole burning in EuYSO. The first frequency comparison, between a single unperturbed spectral hole and a hy
drogen maser, demonstrates a fractional frequency drift rate of $5 times 10^{-18}$ s$^{-1}$. Optical-frequency comparisons between a pattern of spectral holes, a Fabry-Perot cavity, and an Al$^+$ optical atomic clock show a short-term fractional frequency stability of $1 times10^{-15} tau^{-1/2}$ that averages down to $2.5^{+1.1}_{-0.5} times 10^{-16}$ at $tau = 540~s$ (with linear frequency drift removed). Finally, spectral hole patterns in two different EuYSO crystals located in the same cryogenic vessel are compared, yielding a short-term stability of $7 times10^{-16} tau^{-1/2}$ that averages down to $5.5^{+1.8}_{-0.9} times 10^{-17}$ at $tau = 204$~s (with quadratic frequency drift removed).
We characterize the frequency-sensitivity of a cavity-stabilized laser to inertial forces and temperature fluctuations, and perform real-time feed-forward to correct for these sources of noise. We measure the sensitivity of the cavity to linear accel
erations, rotational accelerations, and rotational velocities by rotating it about three axes with accelerometers and gyroscopes positioned around the cavity. The worst-direction linear acceleration sensitivity of the cavity is $2(1) times 10^{-11}$/g measured over 0-50 Hz, which is reduced by a factor of 50 to below $10^{-12}$/g for low-frequency accelerations by real-time feed-forward corrections of all of the aforementioned inertial forces. A similar idea is demonstrated in which laser frequency drift due to temperature fluctuations is reduced by a factor of 70 via real-time feed-forward from a temperature sensor located on the outer wall of the cavity vacuum chamber.
We report a demonstration and quantitative characterization of one-dimensional cavity cooling of a single trapped 88Sr+ ion in the resolved sideband regime. We measure the spectrum of cavity transitions, the rates of cavity heating and cooling, and t
he steady-state cooling limit. The cavity cooling dynamics and cooling limit of 22.5(3) motional quanta, limited by the moderate coupling between the ion and the cavity, are consistent with a simple model [Phys. Rev. A 64, 033405] without any free parameters, validating the rate equation model for cavity cooling.
We demonstrate loading by laser ablation of $^{88}$Sr$^+$ ions into a mm-scale surface-electrode ion trap. The laser used for ablation is a pulsed, frequency-tripled Nd:YAG with pulse energies of 1-10 mJ and durations of 3-5 ns. An additional laser i
s not required to photoionize the ablated material. The efficiency and lifetime of several candidate materials for the laser ablation target are characterized by measuring the trapped ion fluorescence signal for a number of consecutive loads. Additionally, laser ablation is used to load traps with a trap depth (40 meV) below where electron impact ionization loading is typically successful ($gtrsim$ 500 meV).
