The TOTEM experiment at the CERN LHC has measured elastic proton–proton scattering at the centre-of-mass energy
s
=
8
TeV and four-momentum transfers squared, |
t
|, from
6
×
10
-
4
to 0.2 GeV
2
. ...Near the lower end of the
t
-interval the differential cross-section is sensitive to the interference between the hadronic and the electromagnetic scattering amplitudes. This article presents the elastic cross-section measurement and the constraints it imposes on the functional forms of the modulus and phase of the hadronic elastic amplitude. The data exclude the traditional Simplified West and Yennie interference formula that requires a constant phase and a purely exponential modulus of the hadronic amplitude. For parametrisations of the hadronic modulus with second- or third-order polynomials in the exponent, the data are compatible with hadronic phase functions giving either central or peripheral behaviour in the impact parameter picture of elastic scattering. In both cases, the
ρ
-parameter is found to be
0.12
±
0.03
. The results for the total hadronic cross-section are
σ
tot
=
(
102.9
±
2.3
)
mb and
(
103.0
±
2.3
)
mb for central and peripheral phase formulations, respectively. Both are consistent with previous TOTEM measurements.
Resonant label-free biosensors using silicon-on-insulator substrates represent a cutting-edge domain in optical sensing. These devices leverage the high refractive index contrast of ...silicon-on-insulator materials to create highly sensitive, compact sensors. They are crucial for real-time, precise biomolecular detection in healthcare diagnostics, environmental monitoring, and drug discovery, marking a significant stride in microphotonic technology and its practical applications. Different ring-based resonant configurations have been explored in this context, but a definitive comparative assessment of them was previously lacking in the literature. In our work, we experimentally compare four different ring configurations in terms of figure-of-merit, showing that the slotted ring performs better than competitive approaches. A silicon photonic chip including tens of ring resonators was fabricated and optically characterized considering air and aqueous solutions as cladding. The best sensitivity achieved was 64nm/RIU for the slotted ring configuration. The ring displayed a Q-factor in the order of 2.57 × 10 4 , and the best estimated resolution was in the order of 10 -4 RIU in water. The measured figure-of-merit was grater than 200RIU -1 .
Group IV mid-IR photonics Reed, G. T.; Nedeljkovic, M.; Soler Penades, J. ...
2015 IEEE Summer Topicals Meeting Series (SUM),
07/2015
Conference Proceeding
Silicon and germanium are transparent up to approximately 8 μm and 15 μm, respectively, thus offering a range of applications in biochemical and environmental sensing, medicine, astronomy and ...communications 1. Silicon-on-insulator (SOI), can be used only up to 4 μm due to the high absorption loss of silicon dioxide, and therefore alternative material platforms have to be utilized for longer wavelengths. Also, to fully exploit the transparency range of SOI, 400 or 500 nm thick overlayers need to be used rather than the most popular 220 nm platform 2. In this paper we report record low loss MIR SOI strip and slot waveguides, as well as Vernier racetrack configurations. If the buried oxide can be removed and replaced with air, such a platform would be transparent up to 8 μm. We report a robust design based on single etch suspended Si waveguides. Ge-on-Si waveguides have already been demonstrated with losses of 2.5-3.0 dB/cm at λ=5.8 μm by Chang et. al 3 and Shen et. al 4. We report a record low loss in Ge-on-Si and a demonstration of all optical modulation in such waveguides. Although Si is transparent beyond 1.1 μm, it has been demonstrated that it can be used as a photodetector if mid-bandgap states are created by ion implantation. In this paper we show that detection in Si can be extended to up to 2.5 μm by implantation of SOI waveguides with boron. Finally, we also report theoretical analysis of electroabsorption and electrorefraction in Ge.
The TOTEM collaboration at the CERN LHC has measured the differential cross-section of elastic proton–proton scattering at
s
=
8
TeV
in the squared four-momentum transfer range
0.2
GeV
2
<
|
t
|
<
...1.9
GeV
2
. This interval includes the structure with a diffractive minimum (“dip”) and a secondary maximum (“bump”) that has also been observed at all other LHC energies, where measurements were made. A detailed characterisation of this structure for
s
=
8
TeV
yields the positions,
|
t
|
dip
=
(
0.521
±
0.007
)
GeV
2
and
|
t
|
bump
=
(
0.695
±
0.026
)
GeV
2
, as well as the cross-section values,
d
σ
/
d
t
dip
=
(
15.1
±
2.5
)
μ
b
/
GeV
2
and
d
σ
/
d
t
bump
=
(
29.7
±
1.8
)
μ
b
/
GeV
2
, for the dip and the bump, respectively.
In this paper, the wavelength interrogation of optical sensors by novel thermo-optic tunable filters with multiple partially reflected slanted mirrors in silicon-on-insulator (SOI) technology is ...presented. The tunable filter is used both for tunable band selection of broadband light source interrogating the optical sensors, as well as for precise detection of interrogation optical wavelength. New interrogator design is numerically studied by 2-D finite-difference time-domain and finite-element method for a compact structure. The investigation demonstrates the performance of an interrogator on SOI, 1 cm long, having about 1 pm wavelength resolution and 1 ms scanning over 40 nm range at 1550 nm, with an operation power of about 16 mW.
In this paper a detailed investigation of Four Wave Mixing in Silicon-on-Insulator optical waveguides is carried out under pulsed regime. A number of nonlinear effects, such as two photon absorption, ...free carrier absorption, self and cross phase modulation are considered in the analysis, as well as walk-off, group velocity dispersion and third order dispersion. The interesting influence of pulsewidth on the space-time evolution of both signal and idler pulses is presented. Optimized phase matching conditions are found to achieve very efficient wavelength conversion in parametric amplification, considering both degenerate and non degenerate processes. Finally, waveguide parameters are optimized for rib and membrane SOI waveguides.
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