6 research outputs found
Broadband biphoton source for quantum optical coherence tomography based on a Michelson interferometer
Broadband correlated photon pairs (biphotons) are valuable in quantum
metrology, but current generation methods either involve complex nonlinear
structures or lack sufficient bandwidth and brightness. In this work, we
theoretically describe and experimentally demonstrate a novel technique for
generation of a bright collinear biphoton field with a broad spectrum, achieved
by using a tightly focused pump in a bulk nonlinear crystal. As the most
straightforward application of the source, we employ Michelson
interferometer-based quantum optical coherence tomography (QOCT). Utilizing the
source enables the demonstration of record resolution and dispersion
cancellation for this QOCT scheme.Comment: 7 pages, 4 figure
Time-domain Hong-Ou-Mandel interference of quasi-thermal fields and its application in linear optical circuit characterization
We study temporal correlations of interfering quasi-thermal fields, obtained
by scattering laser radiation on a rotating ground glass disk. We show that the
Doppler effect causes oscillations in temporal cross-correlation function.
Furthermore, we propose how to use Hong-Ou-Mandel interference of quasi-thermal
fields in the time domain to characterize linear optical circuits.Comment: 8 pages, 5 figures (main), 4 pages, 1 figure (supplemental
Breaking Rayleigh's curse for multi-parameter objects using BLESS technique
According to the Rayleigh criterion, it is impossible to resolve two
statistically independent point sources separated by a distance below the width
of the point spread function (PSF). Almost twenty years ago it was shown that
the distance between two point sources can be statistically estimated with an
accuracy better than the PSF width. However, the estimation error increases
with decreasing distance. This effect was informally named Rayleigh's curse.
Next, it was demonstrated that PSF shaping allows breaking the curse provided
that all other source parameters except for the distance, are known a priori.
In this work, we propose a new imaging technique based on the target Beam
moduLation and the Examination of Shot Statistics (BLESS). Using the Fisher
information approach, we show that the technique can break Rayleigh's curse
even for unbalanced point sources with unknown centroid and intensity ratio
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Exact mathematical description of the photon annihilation and beam splitter actio
Photoluminescent properties of single crystal diamond microneedles
Single crystal needle-like diamonds shaped as rectangular pyramids were produced by combination of chemical vapor deposition and selective oxidation with dimensions and geometrical characteristics depending on the deposition process parameters. Photoluminescence spectra and their dependencies on wavelength of excitation radiation reveal presence of nitrogen- and silicon-vacancy color centers in the diamond crystallites. Photoluminescence spectra, intensity mapping, and fluorescence lifetime imaging microscopy indicate that silicon-vacancy centers are concentrated at the crystallites apex while nitrogen-vacancy centers are distributed over the whole crystallite. Dependence of the photoluminescence on excitation radiation intensity demonstrates saturation and allows estimation of the color centers density. The combination of structural parameters, geometry and photoluminescent characteristics are prospective for advantageous applications of these diamond crystallites in quantum information processing and optical sensing.Authors are grateful for financial support from Russian Federation President Program for young scientist: Grant# МК-9230.2016.2 (for EAO and FTT) and Grant# MK-5860.2016.2 (for KGK).Peer reviewe
Optical Magnetism and Fundamental Modes of Nanodiamonds
The
optical properties of color centers in nanodiamonds are widely used
in various branches of photonics and interdisciplinary studies. Here,
we report on an experimental study of the fundamental eigenmodes of
subwavelength diamond nanoparticles. The eigenmodes reveal themselves
as scattering resonances, which were measured by single-particle dark-field
spectroscopy and calculated both numerically and analytically. The
resonances experience a red-shift with increasing particle size, and
in the case of an anisotropic particle, they change depending on the
polarization of the input light. As an example of an application,
the Purcell enhancement of the dipole emission from such nanodiamonds
is numerically demonstrated. This study demonstrates a simple way
to improve the efficiency of diamond-based sensors and single-photon
sources by choosing nanoparticles of optimal size and shape