Search results for "interferometry"

Talbot interferometry: a new geometry

1993

Abstract With the Talbot effect, planes are found where the Fresnel diffraction pattern, of a Ronchi ruling, exhibits zero visibility. These planes are exploited to propose a novel geometry for Talbot interferometry, which has high sensitivity. Experimental verifications are included.

‘Nonlocal’ dispersion cancelation with classical light

2009

We show a classical analog of the original nonlocal dispersion cancelation effect in intensity interferometry with stationary light obeying Gaussian statistics. The dispersion compensation is due to the uncorrelation of the spectral components of the radiation. Although this classical counterpart phenomenon is not nonlocal in a strict quantum mechanical sense, it suggests that some second-order interference devices relying on temporal entanglement do not require a quantum light source.

2019

We demonstrate experimentally ghost optical coherence tomography using a broadband incoherent supercontinuum light source with shot-to-shot random spectral fluctuations. The technique is based on ghost imaging in the spectral domain where the object is the spectral interference pattern generated from an optical coherence tomography interferometer in which a physical sample is placed. The axial profile of the sample is obtained from the Fourier transform of the correlation between the spectrally resolved intensity fluctuations of the supercontinuum and the integrated signal measured at the output of the interferometer. The results are in excellent agreement with measurements obtained from a …

Millimeter VLBI of NGC 1052: Dynamics

2016

The LINER galaxy NGC 1052 is an ideal target to study the innermost regions of active galactic nuclei (AGN), given its close distance of about 20 Mpc. The source was observed at 29 epochs from 2005 to 2009 with the Very Long Baseline Array (VLBA) at 43 GHz. Here, we present a kinematic study of its twin-jet system from a subset of 9 epochs at 43 GHz carried out in 2005 and 2006, finding a bright central feature as the dynamic center. The resulting mean velocities of β = v / c = 0 . 46 ± 0 . 08 and β = 0 . 69 ± 0 . 02 for the western and eastern jet, respectively, give hints towards higher velocities in the eastern jet.

Automatic analysis of speckle photography fringes

1997

Speckle interferometry is a technique adequate to metrological problems such as the measurement of object deformation. An automatic system of analysis of such measurements is given; it consists of a motorized x-y plate positioner controlled by computer, a CCD video camera, and software for image analysis. A fringe-recognition algorithm determines the spacing and orientation of the fringes and permits the calculation of the magnitude and direction of the displacement of the analyzed object point in images with variable degrees of illumination. For a 256 x 256 pixel image resolution, the procedure allows one to analyze from three fringes to a number of fringes that corresponds to 3 pixels/fri…

Wavefront Recovery: Shack-Hartmann Aberrometry vs PhaseLift Using a Single Binary Amplitude Modulating Mask

2019

We investigate whether a wavefront can be recovered by using a single mask rotated in four different positions. Results show that PhaseLift can recover the wavefront from intensity measurements using such a kind of modulation.

Introduction into the study of translational diffusion by laser techniques

1988

Breve description de la technique du reseau holographique pour mesurer les coefficients de diffusion de traceurs dans des polymeres et de la technique de spectrometrie de correlation de photon pour la mesure des coefficients de diffusions mutuelle dans des melanges de polymeres

Study of localized pulsed laser depassivation by interferometric probe

1997

Optical interferometry has been implemented as a novel approach to monitor sensitively the localized pulsed laser depassivation of iron or stainless steel samples. This new method, complementing the previous transient current measurements and channel flow double-electrode, is based on the time-resolved measurement of the rear surface displacement of the test sample induced by the laser generated ultrasonic wave. The removal of any material, such as the passive film, from the irradiated surface results in an enhancement of the longitudinal component of the laser generated ultrasonic wave, which is manifested in a change of the displacement characteristics of the rear surface of the test samp…

Comparison of quantitative analysis techniques for the determination of heat seal lacquer layers on aluminum blister foils

2010

For decades a gravimetric method has been common standard for the determination of heat seal lacquers on aluminum blister foils. With the availability of appropriate techniques such as interferometric, infrared reflection absorption spectroscopic (IRRAS), beta backscatter, impedance spectroscopic and eddy current techniques respectively, more efficient determinations can be foreseen which are subject of the present communication. The different methods were compared to each other regarding parameters required for validation of analytical procedures according to the ICH guidelines Q2 (R1) such as linearity, precision, accuracy, robustness and quantitation limits. The interferometric, IRRAS an…

Geometric-phase backaction in a mesoscopic qubit-oscillator system

2012

We illustrate a reverse Von Neumann measurement scheme in which a geometric phase induced on a quantum harmonic oscillator is measured using a microscopic qubit as a probe. We show how such a phase, generated by a cyclic evolution in the phase space of the harmonic oscillator, can be kicked back on the qubit, which plays the role of a quantum interferometer. We also extend our study to finite-temperature dissipative Markovian dynamics and discuss potential implementations in micro- and nanomechanical devices coupled to an effective two-level system. © 2012 American Physical Society.