RESUMEN
Absolute angular rotation rate measurements with sensitivity better than prad/s would be beneficial for fundamental science investigations. In this regard, large frame Earth based ring laser gyroscopes are top instrumentation as far as bandwidth, long-term operation, and sensitivity are concerned. Here, we demonstrate that the GINGERINO active-ring laser upper limiting noise is close to 2×10^{-15} rad/s for â¼2×10^{5} s of integration time, as estimated by the Allan deviation evaluated in a differential measurement scheme. This result is more than a factor of 10 better than the theoretical prediction so far accounted for ideal ring lasers shot-noise with the two beams counterpropagating inside the cavity considered as two independent propagating modes. This feature is related to the peculiarity of real ring laser system dynamics that causes phase crosstalking among the two counterpropagating modes. In this context, the independent beam model is, then, not applicable, and the measured noise limit falls below the expected one.
RESUMEN
Optical resonators simultaneously resonating at different wavelengths are of interest in passive as well as active optical cavities. Dual-wavelength lasers, optical parametric amplifiers and spectrometers, e.g., in high spectral resolution lidar (HSRL) are effectively improved by employing multiply resonant cavities. In particular, HSRL allows us to measure aerosol optical properties without a priori hypotheses. Here we analyze optical dispersion in a HSRL prototype, based on a confocal Fabry-Perot interferometer (CFPI), developed to work at 532 nm (the lidar excitation wavelength). The presence of dispersion should be accounted for when realizing an effective HSRL because a second beam is required to obtain sufficient locking stability. We have performed an experiment in order to measure the dispersion contributions coming from cavity mirror coating and air and evaluate the stability of the transmission peaks in order to optimize the performances of HSRL.
RESUMEN
GINGERino is a large frame laser gyroscope investigating the ground motion in the most inner part of the underground international laboratory of the Gran Sasso, in central Italy. It consists of a square ring laser with a 3.6 m side. Several days of continuous measurements have been collected, with the apparatus running unattended. The power spectral density in the seismic bandwidth is at the level of 10-10 (rad/s)/Hz. A maximum resolution of 30 prad/s is obtained with an integration time of few hundred seconds. The ring laser routinely detects seismic rotations induced by both regional earthquakes and teleseisms. A broadband seismic station is installed on the same structure of the gyroscope. First analysis of the correlation between the rotational and the translational signal is presented.
RESUMEN
Pattern function quantum homodyne tomography (QHT) has been used for characterizing the output of a degenerate below-threshold type-I OPO. The recovered photon number distributions deviated from those relative to Gaussian thermal states. The Kurtosis of the homodyne data confirmed these deviations, thus proving the power of QHT to highlight unexpected features of quantum states.
RESUMEN
We demonstrate, for the first time to our knowledge, the generation of squeezed light by means of soliton self-phase modulation in microstructure fiber. We observe and characterize the formation of solitons in the microstructure fiber at 1550 nm. A maximum squeezing of 2.7 dB is observed, corresponding to 4.0 dB after correcting for detection losses. The dependence of this quantum-noise reduction on various system parameters is studied in detail. Features of the microstructure fiber can be exploited for generation of low-energy continuous-variable entangled pulses for use in all-fiber teleportation experiments.
RESUMEN
We study a Mach-Zehnder nonlinear fiber interferometer for the generation of amplitude-squeezed light. Numerical simulations of experiments with microstructure fiber are performed using linearization of the quantum nonlinear Shroedinger equation. We include in our model the effect of distributed linear losses in the fiber.