Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userPhase locking to a LISA arm: first results on a hardware model
240
0
0.0
(
0
)
Added by
Antonio Francisco Garc\\'ia Mar\\'in
Publication date
2006
fields
Physics
and research's language is
English
Authors
Antonio F Garcia Marin
Ask ChatGPT about the research
No Arabic abstract
We present the first experimental confirmation of the so-called self-phaselocked delay interferometry. This laser frequency stabilization technique consists basically in comparing the prompt laser signal with a delayed version of itself that has been reflected in another LISA satellite 5 million km away. In our table-top experiment, the phase of a voltage-controlled oscillator is stabilized by means of a control loop based on this technique. In agreement with the theory, the measured unity gain frequency is not limited by the inverse of the used delay (1.6 microseconds). In the time domain, the system also behaves as predicted, including the appearance of a quasi-periodic ringing just after the lock acquisition, which decays exponentially. Its initial amplitude is smaller when the loop gain is slowly ramped up instead of suddenly switched on.
rate research
Read More
LISA is an array of three spacecraft flying in an approximately equilateral triangle configuration, which will be used as a low-frequency detector of gravitational waves. Recently a technique has been proposed for suppressing the phase noise of the onboard lasers by locking them to the LISA arms. In this paper we show that the delay-induced effects substantially modify the performance of this technique, making it different from the conventional locking of lasers to optical resonators. We analyze these delay-induced effects in both transient and steady-state regimes and discuss their implications for the implementation of this technique on LISA.
We report on an ultralow noise optical frequency transfer from a remotely located Sr optical lattice clock laser to a Ti:Sapphire optical frequency comb through telecom-wavelength optical fiber networks. The inherent narrow linewidth of the Ti:Sapphire optical frequency comb eliminates the need for a local reference high-finesse cavity. The relative fractional frequency instability of the optical frequency comb with respect to the remote optical reference was $6.7(1) times 10^{-18}$ at 1 s and $1.05(3) times 10^{-19}$ at 1,000 s including a 2.9 km-long fiber network. This ensured the optical frequency comb had the same precision as the optical standard. Our result paves the way for ultrahigh-precision spectroscopy and conversion of the highly precise optical frequency to radio frequencies in a simpler setup.
Arm locking is a technique that has been proposed for reducing laser frequency fluctuations in the Laser Interferometer Space Antenna (LISA), a gravitational-wave observatory sensitive in the milliHertz frequency band. Arm locking takes advantage of the geometric stability of the triangular constellation of three spacecraft that comprise LISA to provide a frequency reference with a stability in the LISA measurement band that exceeds that available from a standard reference such as an optical cavity or molecular absorption line. We have implemented a time-domain simulation of arm locking including the expected limiting noise sources (shot noise, clock noise, spacecraft jitter noise, and residual laser frequency noise). The effect of imperfect a priori knowledge of the LISA heterodyne frequencies and the associated pulling of an arm locked laser is included. We find that our implementation meets requirements both on the noise and dynamic range of the laser frequency.
Borexino was the first experiment to detect solar neutrinos in real-time in the sub-MeV region. In order to achieve high precision in the determination of neutrino rates, the detector design includes an internal and an external calibration system. This paper describes both calibration systems and the calibration campaigns that were carried out in the period between 2008 and 2011. We discuss some of the results and show that the calibration procedures preserved the radiopurity of the scintillator. The calibrations provided a detailed understanding of the detector response and led to a significant reduction of the systematic uncertainties in the Borexino measurements.
We propose an innovative method for proton radiography based on nuclear emulsion film detectors, a technique in which images are obtained by measuring the position and the residual range of protons passing through the patients body. For this purpose, nuclear emulsion films interleaved with tissue equivalent absorbers can be used to reconstruct proton tracks with very high accuracy. This is performed through a fully automated scanning procedure employing optical microscopy, routinely used in neutrino physics experiments. Proton radiography can be used in proton therapy to obtain direct information on the average tissue density for treatment planning optimization and to perform imaging with very low dose to the patient. The first prototype of a nuclear emulsion based detector has been conceived, constructed and tested with a therapeutic proton beam. The first promising experimental results have been obtained by imaging simple phantoms.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
