15 research outputs found
Time-resolved imaging of guided wave phenomena
In the past decade, increasing demand and rapid developments in classical and quantum sciences resulted in advanced novel multipixel single photon detector arrays engineered on a single electronic chip. Silicon single photon avalanche detector (Si-SPAD) is one of the mainstream solution for low level light detection in visible and near-infrared wavelength region due to the dependable amplification of light signal. This thesis mainly focusses on three key experiments to showcase the potential applications of a single photon detector (Megaframe 32) consists of 32×32 square array Si-SPADs with picosecond timing circuits. With ≈ 50 ps timing resolution, each SPAD can perform time-correlated single photon counting independently. First, the concept of multiplexed single-mode wavelength-to-time mapping (WTM) of multimode light was investigated. The spacetime imaging capability of the Megaframe was then demonstrated by imaging the spatial modes emerging from a few-mode fibre enabling WTM of spatial modes. Finally, timeresolved discrete imaging in laser inscribed photonic lattices was demonstrated. By placing a photonic lattice in a linear cavity and re-injecting the output mode profile back to the lattice, the propagation of light was measured in quasi-real time manner. The experimental demonstrations using Megaframe will find applications in Raman spectroscopy, soliton imaging, quantum optics, and discrete waveguide optics
State-recycling and time-resolved imaging in topological photonic lattices
Photonic lattices - arrays of optical waveguides - are powerful platforms for
simulating a range of phenomena, including topological phases. While probing
dynamics is possible in these systems, by reinterpreting the propagation
direction as "time," accessing long timescales constitutes a severe
experimental challenge. Here, we overcome this limitation by placing the
photonic lattice in a cavity, which allows the optical state to evolve through
the lattice multiple times. The accompanying detection method, which exploits a
multi-pixel single-photon detector array, offers quasi-real time-resolved
measurements after each round trip. We apply the state-recycling scheme to
intriguing photonic lattices emulating Dirac fermions and Floquet topological
phases. In this new platform, we also realise a synthetic pulsed electric
field, which can be used to drive transport within photonic lattices. This work
opens a new route towards the detection of long timescale effects in engineered
photonic lattices and the realization of hybrid analogue-digital simulators.Comment: Comments are welcom
In-situ multicore fibre-based pH mapping through obstacles in integrated microfluidic devices
Microfluidic systems with integrated sensors are ideal platforms to study and
emulate processes such as complex multiphase flow and reactive transport in
porous media, numerical modeling of bulk systems in medicine, and in
engineering. Existing commercial optical fibre sensing systems used in
integrated microfluidic devices are based on single-core fibres, limiting the
spatial resolution in parameter measurements in such application scenarios.
Here, we propose a multicore fibre-based pH system for in-situ pH mapping with
tens of micrometer spatial resolution in microfluidic devices. The
demonstration uses custom laser-manufactured glass microfluidic devices (called
further micromodels) consisting of two round ports. The micromodels comprise
two lintels for the injection of various pH buffers and an outlet. The two-port
system facilitates the injection of various pH solutions using independent
pressure pumps. The multicore fibre imaging system provides spatial information
about the pH environment from the intensity distribution of fluorescence
emission from the sensor attached to the fibre end facet, making use of the
cores in the fibre as independent measurement channels. As a proof-of-concept,
we performed pH measurements in micromodels through obstacles (glass and rock
beads), showing that the particle features can be clearly distinguishable from
the intensity distribution from the fibre sensor.Comment: 12 pages of main draft with 10 figures, 2 pages of supplementary
information with 3 figures. Total 14 page
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Observing mode-dependent wavelength-to-time mapping in few-mode fibers using a single-photon detector array
Wavelength-to-time mapping (WTM)—stretching ultrashort optical pulses in a dispersive medium such that the instantaneous frequency
becomes time-dependent—is usually performed using a single-mode fiber. In a number of applications, such as time-stretch imaging (TSI),
the use of this single-mode fiber during WTM limits the achievable sampling rate and the imaging quality. Multimode fiber based WTM
is a potential route to overcome this challenge and project a more diverse range of light patterns. Here, we demonstrate the use of a twodimensional
single-photon avalanche diode (SPAD) array to image, in a time-correlated single-photon counting (TCSPC) manner, the
time- and wavelength-dependent arrival of different spatial modes in a few-mode fiber. We then use a TCSPC spectrometer with a onedimensional
SPAD array to record and calibrate the wavelength-dependent and mode-dependent WTM processes. The direct measurement
of the WTM of the spatial modes opens a convenient route to estimate group velocity dispersion, differential mode delay, and the effective
refractive index of different spatial modes. This is applicable to TSI and ultrafast optical imaging, as well as broader areas such as
telecommunications
In-situ multicore fibre-based pH mapping through obstacles in integrated microfluidic devices
Microfluidic systems with integrated sensors are ideal platforms to study and emulate processes such as complex multiphase flow and reactive transport in porous media, numerical modeling of bulk systems in medicine, and in engineering. Existing commercial optical fibre sensing systems used in integrated microfluidic devices are based on single-core fibres, limiting the spatial resolution in parameter measurements in such application scenarios. Here, we propose a multicore fibre-based pH system for in-situ pH mapping with tens of micrometer spatial resolution in microfluidic devices. The demonstration uses custom laser-manufactured glass microfluidic devices (called further micromodels) consisting of two round ports. The micromodels comprise two lintels for the injection of various pH buffers and an outlet. The two-port system facilitates the injection of various pH solutions using independent pressure pumps. The multicore fibre imaging system provides spatial information about the pH environment from the intensity distribution of fluorescence emission from the sensor attached to the fibre end facet, making use of the cores in the fibre as independent measurement channels. As proof-of-concept, we performed pH measurements in micromodels through obstacles (glass and rock beads), showing that the particle features can be clearly distinguishable from the intensity distribution from the fibre sensor.</p
In-situ multicore fibre-based pH mapping through obstacles in integrated microfluidic devices
Microfluidic systems with integrated sensors are ideal platforms to study and emulate processes such as complex multiphase flow and reactive transport in porous media, numerical modeling of bulk systems in medicine, and in engineering. Existing commercial optical fibre sensing systems used in integrated microfluidic devices are based on single-core fibres, limiting the spatial resolution in parameter measurements in such application scenarios. Here, we propose a multicore fibre-based pH system for in-situ pH mapping with tens of micrometer spatial resolution in microfluidic devices. The demonstration uses custom laser-manufactured glass microfluidic devices (called further micromodels) consisting of two round ports. The micromodels comprise two lintels for the injection of various pH buffers and an outlet. The two-port system facilitates the injection of various pH solutions using independent pressure pumps. The multicore fibre imaging system provides spatial information about the pH environment from the intensity distribution of fluorescence emission from the sensor attached to the fibre end facet, making use of the cores in the fibre as independent measurement channels. As proof-of-concept, we performed pH measurements in micromodels through obstacles (glass and rock beads), showing that the particle features can be clearly distinguishable from the intensity distribution from the fibre sensor.</p
In-situ multicore fibre-based pH mapping through obstacles in integrated microfluidic devices
Abstract Microfluidic systems with integrated sensors are ideal platforms to study and emulate processes such as complex multiphase flow and reactive transport in porous media, numerical modeling of bulk systems in medicine, and in engineering. Existing commercial optical fibre sensing systems used in integrated microfluidic devices are based on single-core fibres, limiting the spatial resolution in parameter measurements in such application scenarios. Here, we propose a multicore fibre-based pH system for in-situ pH mapping with tens of micrometer spatial resolution in microfluidic devices. The demonstration uses custom laser-manufactured glass microfluidic devices (called further micromodels) consisting of two round ports. The micromodels comprise two lintels for the injection of various pH buffers and an outlet. The two-port system facilitates the injection of various pH solutions using independent pressure pumps. The multicore fibre imaging system provides spatial information about the pH environment from the intensity distribution of fluorescence emission from the sensor attached to the fibre end facet, making use of the cores in the fibre as independent measurement channels. As proof-of-concept, we performed pH measurements in micromodels through obstacles (glass and rock beads), showing that the particle features can be clearly distinguishable from the intensity distribution from the fibre sensor