An all-fiber orthogonal-polarized white-noise-modulated laser (AOWL) for short-coherence dynamic interferometry is proposed. Short-coherence laser is achieved by current modulating of a laser diode with the band-limited white noise. A pair of orthogonal-polarized lights with adjustable delay for short-coherence dynamic interferometry are output by the all-fiber structure. In the non-common-path interferometry, the AOWL can significantly suppress the interference signal clutter with 73% side lobe suppression ratio, that improves the positioning accuracy of zero optical path difference. The wavefront aberrations of a parallel plate are measured with the AOWL in the common-path dynamic interferometers, avoiding the fringe crosstalk.
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http://dx.doi.org/10.1364/OE.485945 | DOI Listing |
An all-fiber orthogonal-polarized white-noise-modulated laser (AOWL) for short-coherence dynamic interferometry is proposed. Short-coherence laser is achieved by current modulating of a laser diode with the band-limited white noise. A pair of orthogonal-polarized lights with adjustable delay for short-coherence dynamic interferometry are output by the all-fiber structure.
View Article and Find Full Text PDFA compact system for single-shot sequential holographic imaging (SSSHI) with high temporal resolution and a large field of view is proposed. In this system, a specially designed sequence pulse train generator with a group of diffractive gratings inserted is adopted to simultaneously generate the probe pulse train and the reference pulse train required for recording a single-shot spatial frequency division multiplexing hologram. The system successfully overcomes the walk-off effect of the ultrashort pulse laser in SSSHI and, hence, effectively avoids the influence of the short coherence of ultrashort pulses on the spatial resolution (or field of view) of SSSHI; the complexity of the system and the difficulty in the precise synchronous alignment of the probe and the reference pulses also can be greatly reduced.
View Article and Find Full Text PDFNano Lett
April 2019
Department of Physics , CUNY-City College of New York, New York , New York 10031 , United States.
Optically pumped color centers in semiconductor powders can potentially induce high levels of nuclear spin polarization in surrounding solids or fluids at or near ambient conditions, but complications stemming from the random orientation of the particles and the presence of unpolarized paramagnetic defects hinder the flow of polarization beyond the defect's host material. Here, we theoretically study the spin dynamics of interacting nitrogen-vacancy (NV) and substitutional nitrogen (P1) centers in diamond to show that outside protons spin-polarize efficiently upon a magnetic field sweep across the NV-P1 level anticrossing. The process can be interpreted in terms of an NV-P1 spin ratchet, whose handedness, and hence the sign of the resulting nuclear polarization, depends on the relative timing of the optical excitation pulse.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
March 2019
Max Planck Institute for the Structure and Dynamics of Matter, 22761 Hamburg, Germany;
Energy transfer in terms of excitation or charge is one of the most basic processes in nature, and understanding and controlling them is one of the major challenges of modern quantum chemistry. In this work, we highlight that these processes as well as other chemical properties can be drastically altered by modifying the vacuum fluctuations of the electromagnetic field in a cavity. By using a real-space formulation from first principles that keeps all of the electronic degrees of freedom in the model explicit and simulates changes in the environment by an effective photon mode, we can easily connect to well-known quantum-chemical results such as Dexter charge-transfer and Förster excitation-transfer reactions, taking into account the often-disregarded Coulomb and self-polarization interaction.
View Article and Find Full Text PDFSensors (Basel)
December 2018
STMicroelectronics, 20010 Cornaredo (Mi), Italy.
In this work, we present the results of the opto⁻electro⁻mechanical characterization of tunable micro-lenses, Tlens, performed with a single-spot optical measuring system. Tested devices are composed of a transparent soft polymer layer that is deposited on a supporting glass substrate and is covered by a glass membrane with a thin-film piezoelectric actuator on top. Near-infrared optical low-coherence reflectometry is exploited for both static and low-frequency dynamic analyses in the time domain.
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