No abstract available

[en] A new device for measuring isotope shifts using a photoelectric recording Fabry-Perot spectrometer is described. The light beams of two fixed hollow cathodes are combined by means of a Wollaston prism to follow a common path through the spectrometer and then the two beams are separated by another Wollaston prism. This instrument allows measurements to be made with the same degree of accuracy as conventional set-ups, but is easier to handle and offers the additional advantage of allowing the simultaneous investigation of two light beams. (author)

No abstract available

[en] We propose a fully symmetrical QKD system that enables quantum states to be prepared and measured simultaneously without compromising system performance. Over a 25.6 km fiber channel, we demonstrate point-to-point QKD operations with asymmetric Mach–Zehnder interferometer modules. Two interference visibilities of above 99% indicate that the proposed system has excellent stability. Consequently, the scheme not only improves the feasibility of distributing secret keys, but also enables QKD closer to more practical applications. (paper)

[en] A method for the mathematical processing of digitised Fabry – Perot interferograms is proposed and implemented to eliminate subjective factors and increase the accuracy of measurements. (laser applications and other topics in quantum electronics)

[en] An interferometer has been developed with which it is possible to make accurate plasma density measurements in the presence of density gradients. A modified Mach--Zehnder interferometer employing a linearly polarized scene beam and a circularly polarized reference beam generates signals proportional to the sine and cosine of the phase shift introduced by the plasma. The differential sensitivity of the phase shift measurements is independent of the instantaneous phase angle, and the phase angle may be unambiguously followed through multifringe excursions of the interferometer. The phase shift measurement is also independent of fringe contrast fluctuations caused by the refractive bending of the scene beam by the plasma

No abstract available

[en] A hybrid Fabry–Perot/Michelson interferometer sensor using a dual asymmetric core microstructured fiber is demonstrated. The hybrid interferometer presents three waves. Two parallel Fabry–Perot cavities with low finesse are formed between the splice region and the end of a dual-core microstructured fiber. A Michelson configuration is obtained by the two small cores of the microstructured fiber. The spectral response of the hybrid interferometer presents two pattern fringes with different frequencies due to the respective optical path interferometers. The hybrid interferometer was characterized in strain and temperature presenting different sensitivity coefficients for each topology. Due to these characteristics, this novel sensing head is able to measure strain and temperature, simultaneously

[en] One of the major limitations of atomic gravimeters is represented by the vibration noise of the measurement platform, which cannot be distinguished from the relevant acceleration signal. In this paper we perform atom interferometry measurements of the gravitational acceleration with high resolution without any need for a vibration isolation system or post-corrections based on seismometer data monitoring the residual accelerations at the sensor head. Using two different schemes, a Ramsey and a Ramsey–Bordé interferometer, we measure the velocity variation of freely falling cold atom samples, thus determining the gravitational acceleration experienced by them. Our instrument has a fractional stability of 2.7 × 10⁻⁶ at 1 s of integration time, more than one order of magnitude better than a standard Mach–Zehnder interferometer when operated without any vibration isolation or applied post-correction. Graphical abstract:

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[en] A newly designed Michelson interferometer for Fourier spectroscopy utilizes a nutating retroreflector (cube corner mirror) to generate alterations in geometrical and optical paths. The practical optomechanical design of a Fourier-transform spectrometer incorporating a rotating retroreflector for path-length alteration is considered. (The instrument has been given the name MIROR, for Michelson Interferometer with a Rotating Retroreflector.) Two parameters of the instrument are essential: the maximum optical path difference, which yields the spectral resolution of the instrument, and the diameter of the transmitted beam, which determines the throughput and hence the achievable signal-to-noise ratio. The maximum allowable beam diameter is calculated as a function of the geometry and the orientation of the rotating retroreflector and the other optical components. The geometrical configuration and the orientation of all the optical components with respect to one another are also optimized for the maximum transmitted beam diameter when the required path difference is given. A principal investigation of different possible configurations of the optical components is presented. Then a quantitative optimization for an interferometer employing a retroreflector having a 5-in. (12.7-cm) aperture diameter requiring an optical path difference of more than 10 cm (spectral resolution better than 0.1 cm^-1) is performed. Finally a simplified but enhanced design is described. 10 refs., 15 figs