23 research outputs found
Increasing the photon collection rate from a single NV center with a silver mirror
In the pursuit of realizing quantum optical networks, a large variety of
different approaches have been studied to achieve a single photon source
on-demand. The common goal for these approaches is to harvest all the emission
from a quantum emitter into a single spatial optical mode while maintaining a
high signal-to-noise ratio. In this work, we use a single nitrogen vacancy
center in diamond as a quantum emitter operating at ambient conditions and we
demonstrate an increased photon count rate up to a factor of 1.76 by placing a
silver mirror fabricated on the end facet of an optical fiber near the emitter
Temperature Dependence of a Depth-Encoded System for Polarization-Sensitive Optical Coherence Tomography using a PM Fiber
A polarization-sensitive optical coherence tomography (PS-OCT) system is able
to not only show the structure of samples through the analysis of backscattered
light, but is also capable of determining their polarimetric properties. This
is an extra functionality to OCT which allows the retardance and axis
orientation of a bulk sample to be determined. Here, we describe the
temperature instabilities of a depth-encoded, multiple input state PS-OCT
system, where two waves corresponding to two orthogonal states in the
interrogating beam are delayed using a 5-meter long polarization-maintaning
(PM) fiber. It is shown that the temperature not only affects the delay between
the two relatively delayed waves, but also the amount of mismatched dispersion
in the interferometer, which ultimately affects the achievable axial resolution
in the system. To this end, the technique of complex master/slave
interferometry (CMSI) can be used as an option to mitigate this effect.Comment: The first two authors contributed equally to this wor
Noise of supercontinuum sources in spectral domain optical coherence tomography
In this paper, we investigate the effect of pulse-to-pulse fluctuations of super continuum sources on the noise in spectral domain optical coherence tomography (OCT) images. The commonly quoted theoretical expression for the OCT noise is derived for a thermal light source, which is not suitable if a super continuum light source is used. We therefore propose a new, measurement-based OCT noise model that predicts the noise without any assumptions on the type of light source. We show that the predicted noise values are in excellent agreement with the measured values. The spectral correlation evaluated for the photo detected signal when using a supercontinuum determines the shape of the OCT noise floor, which must be taken into account when characterising the sensitivity roll-off of a supercontinuum-based OCT system. The spectral correlations using both conventional supercontinuum sources and low-noise all-normal dispersion super continuum sources are investigated, and the fundamental physical effects that cause these correlations are discussed
Supercontinuum applications in high resolution non invasive optical imaging
Progress will be presented in adapting supercontinuum sources to a variety of applications with emphasis on signal processing procedures. These are customised to alleviate noise and take full advantage of the large bandwidth and large power spectral density of modern supercontinuum sources