Incoherent averaging of phase singularities in speckle-shearing interferometry

AbstractInterference patterns provide direct measurement of coherent propagation of matter waves in quantum systems. Superfluidity in Bose–Einstein condensates of excitons can enable long-range ballistic exciton propagation and can lead to emerging long-scale interference patterns. Indirect excitons (IXs) are formed by electrons and holes in separated layers. The theory predicts that the reduced IX recombination enables IX superfluid propagation over macroscopic distances. Here, we present dislocation-like phase singularities in interference patterns produced by condensate of IXs. We analyze how exciton vortices and skyrmions should appear in the interference experiments and show that the observed interference dislocations are not associated with these phase defects. We show that the observed interference dislocations originate from the moiré effect in combined interference patterns of propagating condensate matter waves. The interference dislocations are formed by the IX matter waves ballistically propagating over macroscopic distances. The long-range ballistic IX propagation is the evidence for IX condensate superfluidity.

Download Full-text

Wavefront dislocations reveal the topology of quasi-1D photonic insulators

Nature Communications ◽

10.1038/s41467-021-23790-w ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Clément Dutreix ◽

Matthieu Bellec ◽

Pierre Delplace ◽

Fabrice Mortessagne

Keyword(s):

Local Density ◽

Topological Defects ◽

Wave Functions ◽

Topological Classification ◽

Local Density Of States ◽

Topological Phase Transition ◽

Interference Fringes ◽

Classical Wave ◽

Phase Singularities

AbstractPhase singularities appear ubiquitously in wavefields, regardless of the wave equation. Such topological defects can lead to wavefront dislocations, as observed in a humongous number of classical wave experiments. Phase singularities of wave functions are also at the heart of the topological classification of the gapped phases of matter. Despite identical singular features, topological insulators and topological defects in waves remain two distinct fields. Realising 1D microwave insulators, we experimentally observe a wavefront dislocation – a 2D phase singularity – in the local density of states when the systems undergo a topological phase transition. We show theoretically that the change in the number of interference fringes at the transition reveals the topological index that characterises the band topology in the insulator.

Download Full-text

CURVATURE MEASUREMENT OF THIN PLATES BY MOIRÉ SHEARING INTERFEROMETRY

Experimental Techniques ◽

10.1111/j.1747-1567.1992.tb01266.x ◽

1992 ◽

Vol 16 (3) ◽

pp. 23-24 ◽

Cited By ~ 6

Author(s):

L. Wang ◽

D. Yun

Keyword(s):

Thin Plates ◽

Shearing Interferometry ◽

Curvature Measurement

Download Full-text

The nonmodular topological phase and phase singularities

Physics Letters A ◽

10.1016/j.physleta.2011.08.019 ◽

2011 ◽

Vol 375 (41) ◽

pp. 3562-3569

Author(s):

Rajendra Bhandari

Keyword(s):

Topological Phase ◽

Phase Singularities

Download Full-text

Dual-hologram shearing interferometry with regulated sensitivity

10.1117/12.316453 ◽

1998 ◽

Author(s):

Gregory R. Toker ◽

Daniel Levin

Keyword(s):

Shearing Interferometry

Download Full-text

Optical arbitrary waveform characterization via dual-quadrature spectral shearing interferometry

Optics Express ◽

10.1364/oe.17.003381 ◽

2009 ◽

Vol 17 (5) ◽

pp. 3381 ◽

Cited By ~ 24

Author(s):

Houxun Miao ◽

Daniel E. Leaird ◽

Carsten Langrock ◽

Martin M. Fejer ◽

Andrew M. Weiner

Keyword(s):

Shearing Interferometry ◽

Arbitrary Waveform

Download Full-text

Study on Measurement of Thin Film Thickness with Lateral Shearing Interferometry

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.718-720.848 ◽

2013 ◽

Vol 718-720 ◽

pp. 848-852

Author(s):

Jun Hong Su ◽

Ying Shi ◽

Jin Man Ge

Keyword(s):

Film Thickness ◽

Transform Method ◽

Shearing Interferometry ◽

Platform Process ◽

Fast Fourier Transform Method ◽

Lateral Shearing ◽

Phase Unwrap ◽

Technical Indicator ◽

Lateral Shearing Interferometry ◽

Shearing Interference

The film thickness is an important technical indicator of film devices, and its accuracy directly affects various performances of optical components. In fabrication process of film device, fast and accurate measurement of film thickness has positive significance on product quality control. In this paper, measure film thickness with lateral shearing interferometry. Collect interferograms through structured lateral shearing interference platform, process interferogram with Fast Fourier Transform method to extract phase, unwrap the wrapped phase to achieve phase value. Finally, calculate film thickness based on lateral shearing interference principle. The thickness of sample is 119.6800nm measured by this method, basically the same with the result 120.6036nm that measured by ZYGO interferometer. This experiment shows that lateral shearing interferometry not only suit to measurement of film thickness, but also abundant high-precision method of measuring film thickness, and has high practical value.

Download Full-text