119207145
Mid-Infrared Frequency Comb Fourier Transform Spectrometer
Optical frequency-comb-based-high-resolution spectrometers offer enormous potential for spectroscopic applications. Although various implementations have been demonstrated, the lack of suitable mid-infrared comb sources has impeded explorations of molecular fingerprinting. Here we present for the first time a frequency-comb Fourier transform spectrometer operating in the 2100-to-3700-cm-1 spectral region that allows fast and simultaneous acquisitions of broadband absorption spectra with up to 0.0056 cm-1 resolution. We demonstrate part-per-billion detection limits in 30 seconds of integration time for various important molecules including methane, ethane, isoprene, and nitrous oxide. Our system enables precise concentration measurements even in gas mixtures that exhibit continuous absorption bands, and it allows detection of molecules at levels below the noise floor via simultaneous analysis of multiple spectral features. This system represents a near real-time, high-resolution, high-bandwidth mid-infrared spectrometer which is ready to replace traditional Fourier transform spectrometers for many applications in trace gas detection, atmospheric science, and medical diagnostics.
124924859
Direct Observation of SU(N) Orbital Magnetism
31462099
Precision stabilization of femtosecond lasers to high-finesse optical cavities
We report on direct stabilization of a femtosecond laser by a high-finesse passive optical cavity. Detailed comparison of two distinct stabilization schemes leads to new understanding of the optimum conditions for cavity stabilization and limitations on the ability to transfer the frequency stability of the cavity to the microwave domain. The stability of the frequency comb is explored in both the optical and the radio frequency domain. With an independent, stable cw laser, we verify that the linewidth and stability of the optical comb components, respectively, reach below 300 Hz and 53 10 ˛14 at 1 s averaging time, both limited by the
2120691
Optical interferometers with reduced sensitivity to thermal noise
Thermal phase noise in optical interferometry can be compensated by exploiting coherence for underlying stochastic displacements and strains. The phase upon reflection from a fluctuating mirror's surface can thereby have reduced sensitivity to thermal noise.
119590216
Irradiation studies of multimode optical fibres for use in ATLAS front end links
The radiation tolerance of three multimode optical fibres has been investigated to establish their suitability for the use in the front-end data links of the ATLAS experiment. Both gamma and neutro ...
55746504
The versatile link, a common project for super-LHC
A common project to develop a bi-directional, radiation tolerant, high speed (4.8 Gb/s) optical link for future high energy physics experiments is described. Due to be completed in 2012, it targets the upgrade programs of detectors installed at CERN's Large Hadron Collider (LHC). The development of radiation and magnetic field tolerant opto-electronic devices, fibre and connectors is described. Both Single-Mode and Multi-Mode versions of the system operating respectively at 850 nm and 1310 nm wavelength are proposed. First results at component and system level are presented, based mostly on commercially available devices.
33025887
Lifetime Test for Optical Transmitters in the ATLAS Liquid Argon Calorimeter Readout System 1
Accelerated lifetime test has been carried out for 147 days on the custom-made optical transmitters used in the ATLAS Liquid Argon Calorimeter front-end electronics readout system. The lifetime of these optical transmitters is estimated to be greater than 200 years and exceeds the design goal for the LHC. The random failure rate has been estimated at 9.6×10 -7 per hour at 90% confidence level.
17189846
A Serializer ASIC at 5 Gbps for Detector Front-end Electronics Readout
Optical data links are used in detector front-end electronics readout systems of experiments in the Tevatron and the LHC. Optical links in high energy particle physics experiments usually have special requirements such as radiation tolerance, ultra high reliability and low power dissipation. These requirements are often not met by commercial components which are designed for applications in non-radiation, accessible (for maintenance) environment, and for multi-vendor systems so the parts must comply with certain standards. Future HEP experiments such as the upgrades for the sLHC call for optical links with ultra high data bandwidth, higher radiation tolerance and ultra low power dissipation. To meet these challenges and in particular those in the upgrade for the ATLAS Liquid Argon Calorimeter readout that calls for an optical link system of 100 Gbps for each front-end board, we adopted a full custom front-end electronics system design based on application specific integrated circuits. Reported here are the development and test results of two circuits: a 5 Gbps serializer and a 5 GHz phase locked loop, and a block diagram design for the 100 Gbps optical link.
15277817
Electronics of the ATLAS Liquid Argon calorimeter and its precision calibration
The Liquid Argon sampling calorimeter is a key detector component in the ATLAS experiment at the LHC, designed to provide precision measurements of electrons, photons, jets and missing transverse energy. In this note we present the detector readout electronics system and its precision calibration. The system has 182,468 channels with more than 16-bit dynamic range. The contribution to the relative energy resolution constant term due to the calibration uncertainty is below 0.25%. The radiation tolerant optical link between the detector front-end and the data acquisition back-end is also discussed.