Measured data for "Billion Q-factor in BaMgF4 WGM resonators"

This dataset contains the experimental measurement data presented in the article "Billion Q-factor in BaMgF₄ Whispering-Gallery-Mode Resonators". The study reports the fabrication of ultra-high-quality (Q ~ 10⁹) barium magnesium fluoride (BaMgF₄) whispering-gallery-mode microresonators and demonstrates their performance from ultraviolet to near-infrared wavelengths, including optical frequency comb generation at 1550 nm.The repository includes the following data files: fig2b_ringdown_trace.scv: Time-domain ring-down trace used to extract the loaded quality factor (Q_L) at 1550 nm. The exponential decay fit yields Q_L ≈ 1.0 × 10⁹. The file contains two columns: Time (s), Trigger (s), optical power (a.u.) and reference (a.u.). Recorded by Keysight InfiniiVision MSO-X 4154A oscilloscope. fig2c_transmission_spectrum_398nm.scv: Raw time-domain data for the transmission spectrum of the BaMgF₄ microresonator measured at 398 nm wavelength. The loaded Q-factor of ~1.25 × 10⁸ was extracted by fitting a Lorentzian function to the resonance dip using standard MATLAB routines. The file contains three columns:Time (s) – time scan during laser frequency sweep. Optical power (a.u.) – transmitted optical signal through the tapered fiber. Reference signal (a.u.) – signal from a reference interferometer for frequency calibration. fig2e_lum.scv: Luminescence spectrum obtained using a mini spectrometer TM-VIS/NIR. The file contains the next columns: wavelength (nm) and several columns of optical power (a.u.) recorded luminescence spectrum. fig3a.csv: Optical spectrum of the generated Kerr frequency comb at a pump power of 100 mW (Fig. 3a). The comb has a free spectral range of 42 GHz. The file contains two columns: wavelength (nm) and optical power (dBm). The measurement was done by the Yokogawa AQ6370D optical spectrum analyzer. fig3bscv.scv: Optical spectrum of the broadband Kerr frequency comb at the maximum pump power of 500 mW (Fig. 3b). The spectral width exceeds 30 nm. The file contains two columns: wavelength (nm) and optical power (dBm). The measurement was done by the Yokogawa AQ6370D optical spectrum analyzer. fig4b_laser_comb_spectrum.scv: Output spectrum from the fiber laser cavity where the BaMgF₄ resonator acts as a nonlinear mirror (Fig. 4b). The comb is ~20 nm wide with a mode spacing of ~1 GHz. The file contains two columns: wavelength (nm) and optical power (dBm). The measurement was done by the Yokogawa AQ6370D optical spectrum analyzer.SEM_microresonator_image.tif: Original scanning electron microscope (SEM) image of the fabricated BaMgF₄ microresonator. The image was done by Quattro S SEM, demonstrating the final resonator geometry and surface quality achieved after the multistage fabrication process (single-point diamond turning, chemo-mechanical polishing, and annealing).