Search results for "Modula"
showing 10 items of 1481 documents
A large-area modular electromagnetic shower detector for the CERN intersecting storage rings
1979
The authors describe the design and performances large-area (13 m/sup 2/) shower detector built for an experiment at the CERN ISR to detect electrons and gamma rays with energies up to 4 GeV. The main characteristics of the detector are: a) linearity of the energy response from 0.5 to 4 GeV; b) good energy, time and space resolutions; c) modularity of the mechanical assembly; d) low cost of construction. (3 refs).
Nonlinear spectral compression in fibre as a power-limiting device
2017
Spectral compression (SC) by self-phase modulation in optical fibre has been known for a long time and has since been reported for various parameters [1]. In this paper, we analyse the impact of amplitude fluctuations and a degraded optical signal-to-noise ratio (OSNR) of the seed pulses on the SC process by means of extensive nonlinear Schrodinger equation numerical simulation. Remarkably, our results show that the SC is rather stable against these pulse degradation factors, thereby revealing its potential for use in the context of optical regeneration of intensity-modulated signals. We therefore propose an optical scheme combining SC with an optical bandpass filter (OBPF) centred at the c…
Ultracompact and Low-Power Plasmonic MZI Switch Using Cyclomer Loading
2015
We present a $2\times 2$ hybrid silicon-plasmonic thermooptic (TO) asymmetric Mach–Zehnder interferometric (MZI) switch having only 40- $\mu \text{m}$ long active cyclomer-loaded plasmonic phase arms. It requires less than 12 mW of power and has 2/5- $\mu \text{s}$ ON/OFF-times, respectively, a modulation depth higher than 90% and a 13.2-dB extinction ratio. Data traffic evaluation has been carried out using 10-Gb/s nonreturn-to-zero streams, yielding error-free operation at both switching states with power penalties ranging between 1 to 4.8 dB. The use of the cyclomer loading having a higher TO coefficient than polymethyl methacrylate has resulted to the smallest footprint among plasmonic …
State-selective chirped adiabatic passage on dynamically laser-aligned molecules
2005
We show that rovibrational state selectivity can be achieved by chirped adiabatic passage of molecules that are adiabatically aligned by a nonresonant laser field. We develop the tools to design the appropriate frequency and amplitude modulations that allow us to select a given route in the Hilbert space that leads to a final complete excitation of the chosen state, by infrared or by Raman processes. This method allows us to select a given vibrational state in a well-defined rotational $J$ state.
Lineshape-asymmetry elimination in weak atomic transitions driven by an intense standing wave field
2018
Owing to the ac-Stark effect, the lineshape of a weak optical transition in an atomic beam can become significantly distorted, when driven by an intense standing wave field. We use an Yb atomic beam to study the lineshape of the 6s2 1S0 -> 5d6s 3D1 transition, which is excited with light circulating in a Fabry-Perot resonator. We demonstrate two methods to avoid the distortion of the transition profile. Of these, one relies on the operation of the resonator in multiple longitudinal modes, and the other in multiple transverse modes.
Locust: C++ software for simulation of RF detection
2019
The Locust simulation package is a new C++ software tool developed to simulate the measurement of time-varying electromagnetic fields using RF detection techniques. Modularity and flexibility allow for arbitrary input signals, while concurrently supporting tight integration with physics-based simulations as input. External signals driven by the Kassiopeia particle tracking package are discussed, demonstrating conditional feedback between Locust and Kassiopeia during software execution. An application of the simulation to the Project 8 experiment is described. Locust is publicly available at https://github.com/project8/locust_mc.
Amplitude modulation technique for designing metalenses with apodized and enhanced resolution focal spots
2017
Abstract In this paper we show that engineering both phase and amplitude of the scattered light can be employed in designing metalenses with either higher resolution or apodized focal spots. C-shaped split-ring micro-resonators (CSRRs) with different geometrical parameters are selected to have a full control of amplitude and phase. While phase engineering is necessary for light focusing, amplitude modulation of the scattered wave can be applied to characterize the focal point properties such as resolution gain and sidelobe level. We show that both axial and transverse resolution improvement or apodization is possible in the far-field region by applying proper amplitude function. Amplitude m…
An all-fiber RF modulation technique: frequency response calibration of optical detectors
1995
Two all-fiber Mach-Zender interferometers have been designed to generate RF modulated light at 633 nm and 830 nm. The interferometers are scanned with a piezoelectric tube driven at its fundamental frequency of resonance. The actual experimental arrangement covers the frequency range 1 kHz to 1 GHz. The technique combines several interesting features such as the simplicity, the stability and reliability of all-fiber systems and the use of low-frequency electronics to control and generate the RF modulated light. >
Bright and dark optical solitons in fiber media with higher-order effects
2002
We consider N-coupled higher-order nonlinear Schrodinger (N-CHNLS) equations which govern the simultaneous propagation of N optical fields in fiber media with higher-order effects. Bright and dark soliton solutions are derived using Hirota bilinear method for the general cross-coupling ratio between the parameters of self-phase modulation and cross-phase modulation effects. By means of coupled amplitude-phase formulation also, similar kind of dark soliton solutions are obtained. It is found that the parametric conditions for the simultaneous propagation of N dark solitons from both the methods are the same.
Phase retrieval of a Kolmogorov phase screen from very sparse data using four binary masks
2020
We investigate experimentally the phase retrieval of a Kolmogorov phase screen from very sparse data by modulating its amplitude with four binary masks and compare the retrieved phase screen to the ground truth measured with a surface profiler. Previously, we have shown in simulations that this kind of modulation can be successfully used for the phase retrieval of a Kolmogorov phase screen. After subtracting the ground truth from the retrieved phase screen, the root-mean-square error decreased from 0.14 µm to 0.10 µm. We conclude that a Kolmogorov phase screen can be recovered using simple modulation and very sparse data.