A suspension-point interferometer (SPI) is an auxiliary interferometer for active vibration isolation, implemented at the suspension points of the mirrors of an interferometric gravitational wave detector. We constructed a prototype Fabry-Perot interferometer equipped with an SPI and observed vibration isolation in both the spectrum and transfer function. The noise spectrum of the main interfer...

In this work the results of the theoretical studies of photonic integrated circuit refractive index sensor based on quasi1D Bragg grating configurations which act as a Fabry-Perot interferometers are presented. The variation of the medium refractive index is detected by monitoring the shift of the spectral maxima of the Fabry-Perot cavity. The sensor has been designed using the analytical expre...

Rayleigh-Brillouin spectra for heated nitrogen gas were measured by imaging the output of a Fabry-Perot interferometer onto a CCD array. The spectra were compared with the theoretical 6-moment model of Rayleigh-Brillouin scattering convolved with the Fabry-Perot instrument function. Estimates of the temperature and a dimensionless parameter proportional to the number density of the gas as funct...

Power recycling was implemented on a fully suspended prototype interferometer with arm lengths of 20 m. A wave-front-sensing technique for alignment control of the suspended mirrors was also implemented, which allowed for several hours of stable operation. A power-recycling gain of greater than 12 was achieved, a significant increase over the highest gain in a suspended mirror Fabry-Perot Miche...

Internal waves are a ubiquitous and significant means of momentum and energy transport in the oceans, atmosphere, and astrophysical bodies. Here, we show that internal wave propagation in nonuniform density stratifications, which are prevalent throughout nature, has a direct mathematical analogy with the classical optical problem of a Fabry-Perot multiple-beam light interferometer. We rigorousl...

For photoacoustic imaging, usually point-like detectors are used. As a special sensing technology for photoacoustic imaging, integrating detectors have been investigated that integrate the acoustic pressure over an area or line that is larger than the imaged object. Different kinds of optical fiber-based detectors are compared regarding their sensitivity and resolution in three-dimensional phot...