Status of Virgo: Brief history, Commissioning experience, Latest performances

Francesco Fidecaro
E-mail: francesco.fidecaro at df.unipi.it
Univ. Of PISA, PISA, Italy

The construction of a 3 km size scientific instrument is a challenge, and it took almost 20 years from first concepts to reaching the design sensitivity. In this talk, the main steps in the construction and commissioning of the Virgo interferometer will be described as well as some developments that took place in view of the second generation of interferometric detectors for gravitational waves.

IndIGO - Current Status and Future Plans

Tarun Souradeep
IUCAA, Pune, India

IndIGO, the Indian Initiative in Gravitational-wave Observations, is an initiative to bring together available GW related experimental capabilities in national laboratories, collate and enhance the existing theoretical, data analysis and computational expertise to spearhead a coordinated multi-institutional Indian participation and contribution to a gravitational-wave observatory in the Asia-Pacific region as part of the global GW astronomy network. The IndIGO consortium, formed in Aug 2009, is currently exploring the challenging possibility of hosting LIGO-India.

Advanced Virgo and the 2nd Generation Interferometers Network

Giovanni Losurdo
E-mail: losurdo at fi.infn.it
INFN, Firenze, Italy

The era of first generation of interferometric detectors is ending. No detection has been done so far. However, remarkable results have been achieved: the design sensitivity has been approached (and in some cases even exceeded) together with good robustness and reliability. A world wide network of detectors has been realized. The data collected so far have allowed to put upper limits on several sources. Some second generation technologies have been tested on the first generation detectors. The scenario for the next years is very exciting. The projects to upgrade LIGO and Virgo to second generation interferometers, capable to increase the detection rate by a factor ~1000 have been funded recently and their construction has started. Moreover, GEO600 is being upgraded, LCGT will be realized in Japan and the option to move one LIGO interferometer in India is being considered. In the talk we will discuss the status and plans of the Advanced Virgo project, in the framework of the international effort to create a network of second generation interferometers, aiming to open the way to gravitational wave astronomy.

Hunting Gravitational Waves with a Multi-Detector Antenna

Archana Pai
E-mail: archana at iisertvm.ac.in
IISER, Thiruvananthapuram, India

Gravitational Wave Data analysis with a phase-coherent multi-detector data stream has many advantages over searching gravitational wave with a single detector. The upgraded version of the existing LIGO-VIRGO network and an addition of a detector in Japan as well as possibly in India would pave way for such a multi-detector gravitational wave antenna to becomes a reality. In this talk, I shall review the advantages of the multi-detector antenna over a single detector, signal specific different approaches adopted for the multi-detector schemes and the future challenges in multi-detection.

The Virgo suspension system for seismic noise suppression

Franco Frasconi
E-mail: franco.frasconi at pi.infn.it
INFN, Pisa, Italy

Seismic noise is one of the limiting factors of ground based interferometers for Gravitational Waves detection. Since the beginning the Virgo interferometer has been conceived with a sophisticated seismic isolation system of the optical components based on a mechanical structure called Super-attenuator. It has been developed to extend the detection bandwidth in the low frequency region where a large number of gravitational waves sources are expected. The Super-attenuator has been designed to suppress the seismic noise transmission to the mirror level by more than ten order of magnitude starting from a few Hz. A detailed description of its working principle, its main features together with the attenuation performance obtained operating it over a time period of about ten years are presented in this talk. The reached results in term of seismic noise suppression are compared with the requirements for the next generation Gravitational Wave interferometers while some improvements to be implemented on the second generation suspension system for the Advanced Virgo project are described.

The IndIGO 3-m Advanced Prototype Interferometer Detector at TIFR: Features and Goals

C.S. Unnikrishnan
E-mail: unni at tifr.res.in
TIFR, Mumbai, India

One of the several steps the IndIGO consortium has taken to develop gravitational wave research an astronomy in India is to conceive a prototype detector that can serve as a research and development platform as well as an advanced training facility. The small scale interferometer that was fully funded this year at TIFR, Mumbai is designed to incorporate several features of present generation detectors including the use of quantum squeezed light in its advanced phase. I will present the basic design features and the strategies to achieve the goals in a relatively short time, especially in the context of the plans for an advanced large scale detector in India. The detector will also be employed in the precision measurements of short range forces including the Casimir force with unprecedented sensitivity.

Focus on technology: adaptive optical systems for future gravitational wave interferometers

Alessio Rocchi
E-mail: alessio.rocchi at roma2.infn.it
INFN, Rome Tor Vergata, Italy

Intrinsic optical defects and thermal lensing in core optics of gravitational wave interferometers can represent a strong limitation to the operation and sensitivity of these detectors. Thermal effects have already been observed in the present instruments and will become more relevant in the future upgraded interferometers, due to the much higher circulating power. Here we describe the thermal compensation system designed to be installed in Advanced Virgo to mitigate �cold� and �hot� optical aberrations and its possible evolutions.

Accelerator Technology,Magnetic confinement of Plasmas and Magnet for INO project

Sanjay Malhotra
E-mail: sanjaym at barc.gov.in
BARC, Mumbai, India

Abstract text

The European Gravitational Observatory, EGO: its role in international GW research

Federico Ferrini
E-mail: federico.ferrini at ego-gw.it
EGO, Italy

The European Gravitational Observatory, EGO, created by CNRS and INFN near Pisa, has as main purpose the construction and operation of the interferometer Virgo and of its upgrades. On a wider perspective, EGO is charged to promote development in the field of gravitational waves research in Europe.Coherently, EGO has coordinated the first initial study for the Einstein Telescope Observatory and is preparing to afford the future challenges.
(To be presented by Jean-Yves Vinet)

Indo-Italian collaboration in Science & Technology

Lidia Szpyrkowicz
E-mail: scientifico.newdelhi at esteri.it
Scientific Attache, Embassy of Italy, New Delhi, India

Abstract text abstract text..

IndIGO GW Data Centre Plans

Sanjeev Dhurandhar
E-mail: sanjeev at iucaa.ernet.in

LMA: the Virgo mirrors facility

Raffaele Flaminio
E-mail: r.flaminio at lma.in2p3.fr
Laboratoire des Mat�riaux Avanc�s CNRS/IN2P3, Villeurbanne, Lyon, France

The Laboratoire des Mat�riaux Avanc�s (LMA) has been set up on the campus of the University Claude Bernard Lyon 1 during the construction of the Virgo project. This infrastructure includes clean rooms, coating chambers and optical benches devoted to the development and characterization of the large laser mirrors for the Virgo interferometer. The first part of this presentation will review the work done at LMA for Virgo. Then it will describe the subsequent R&D phase as well as the work currently ongoing for Advanced Virgo and Advanced LIGO.

Diffraction-free laser sources: Bringing the coolest physical phenomena to existence

Manasadevi P. Thirugnanasambandam
E-mail: manasa at ils.uec.ac.jp
Ueda Laboratory, Tokyo, Japan

Diffraction-free Bessel beams, since the days they were proposed to exist by Durnin et al., have only been a dream and for decades hence, researches have worked towards bringing the dream to reality. Though we have partially succeeded towards this goal, the methods that have been reported are inefficient mode-conversion techniques. The methods can be broadly classified into two categories: (i) To consider a set of plane waves propagating on a cone and (ii) Considering an optical Fourier transform of a ring. These techniques, though successful, have restricted the applications of these non-diffracting beams to just microbiology and micro-manipulation. While non-diffracting properties come into real use when they can propagate over long-range in distance and can be generated at high powers, the current setup is nowhere close to exploiting this coolest phenomenon.

Our work has targeted this weakness and we have succeeded in coming up with an efficient yet simple and economical method to generate non-diffracting beams that completely defines the entire range of their applications. We use a plano-convex glass lens with strong aberrations (which has so far been considered a disadvantage with laser sources) inside a ceramic laser cavity and enabled mode selection generating near-diffraction free laser modes. The modes thus generated had stable near-diffraction free properties for over 40 m of propagation distance. This is the first ever demonstration of such a phenomenon in experiments. Intra-cavity mode coupling enabled by the intra-cavity spherically aberrated lens has been proved to be the reason behind the possibility of such laser modes.

Our future work is channeled towards proving the efficiency of this new method by generating high-power non-diffracting robust laser sources. With applications of diffraction-free beams being very obvious in astronomy as guide stars and alignment of long-range systems, the future diffraction-free laser sources is definitely BIG.

Numerical propagation of light beams in refractive and diffractive devices

Jean-Yves Vinet
E-mail: jean-yves.vinet at obs-nice.fr, vinet at oca.eu
OCA-CNRS, Nice, France

Numerical simulation of Gravitational Wave interferometers is a crucial task especially for advanced systems involving high finesse cavities and high laser power. Native or thermally induced defects must be studied, and their impact on the sensitivity must be assessed. The propagation of scattered light is also an important issue. We present a short review of the various approaches tested in the context of Virgo then Advanced Virgo design.

Radiometric searches of GW

Sanjit Mitra
E-mail: sanjitm at gmail.com
IUCAA, Pune, India

GW astronomy aims to probe different kinds of sources, Stochastic Gravitational Wave Background (SGWB) is one of the most interesting ones. The universe is expected to have an SGWB generated by un-modeled/unresolved astrophysical and cosmological sources. Statistically isotropic cosmological SGWB has already caught lot of attention, as it is a direct probe of slow roll inflation. On the other hand, anisotropic SGWB, generated by un-modeled/unresolved astrophysical sources in the nearby universe, dominates the background by several orders of magnitude and can provide important information about the nearby universe not accessible to electromagnetic astronomy. A GW radiometer algorithm is well suited for probing SGWB. We present a general analysis framework to probe SGWB in any given basis using a network of detectors and the technique of ``folding'' for efficient application of the radiometer algorithm on real data.

Quantitative analysis of the performance of a network of GW detectors is useful for studying the importance of the network and to identify potential scientific results that can be extracted from data. We propose different figures of merit to quantify the performance of a network using the radiometer algorithm. Simplicity of this method leads to results which are relatively straightforward to compute, yet provide vital understanding of the overall network performance.

Third Generation of GW observatories: The ET project

Michele Punturo
E-mail: michele.punturo at pg.infn.it
INFN, Perugia, Italy and EGO, Italy

The advanced gravitational wave (GW) �detectors (advanced Virgo, aLIGO, LCGT, �) will allow, in few years from now, to detect the GW emission from few astrophysical �sources (BNS, CW, �.), but �to open the era of the GW precision astronomy will be necessary to gain another order of magnitude in the detector sensitivity. 3rd generation GW observatories, based on new infrastructures and new technologies, are promising to reach this ambitious target. The design achievements, the status and the perspectives of the Einstein Telescope (ET), the European project for a 3rd generation GW observatory, will be discussed.

Sources of GW for 2G and 3G detectors

Sukanta Bose
E-mail: sukanta at mail.wsu.edu
Washington state university, Pullman, USA

The maiden second generation (2G) detector is expected to start taking data in a couple of years from now. Other LIGO and Virgo detectors of that class will join in the following years. Together they will pave the way for direct detections of gravitational wave (GW) signals and plant the first steps in GW astronomy. In the first part of the talk I will describe the type of sources they will target and the problems we are working on now to enable their detection.

The construction of third generation (3G) detectors will likely happen after the first successes of 2G detectors. That has, however, not stopped some of us from envisaging the maximal GW science potential that may be realizable with an earth-based detector within a decade of the advent of the 2G detectors. The 3G detectors will be ten times more sensitive and will hear signals close to as low as 1Hz, rather than 10Hz for their 2G predecessors. They will shed light on the equation of state of neutron stars and, perhaps, tell us why pulsars glitch. If they detect intermediate mass binary black holes they will likely unravel what kind of environments seeded their formation. They will also probe the equation of state of the dark energy, independent of supernova Type Ia observations. In the second part of my talk I will discuss the GW sources that 3G detectors will observe and the astrophysics they will teach us.

Thermal noise reduction using cryogenic techniques

Fulvio Ricci
E-mail: fulvio.ricci at roma1.infn.it
INFN, Universita di Roma La Sapienza, Italy

The fundamental limitations at low frequency of the sensitivity of the 2nd generation of gravitational wave detectors are given by the seismic noise, the related gravitational gradient noise and the thermal noise of the suspension last stage and of the test masses. To circumvent these limitations it has been proposed to set up the detecter in an underground site to limit the effect of the seismic noise, and cryogenic facilities to cool down the mirrors to directly reduce the thermal vibration of the test masses. The Einstein Telescope design study is addressing the basic questions how to realize this new instrument. In this talk we will focus on the main processes contributing to thermal noise limit and then we sketch alternative approaches for the mirror cooling.

Single-photon optics and instrumentation

Pradeep Kumar
E-mail: pradeepk at iitk.ac.in
IIT, Kanpur, India

In this talk I cover our fields of interest in single-photon optics. We discuss entangled and squeezed state generation and detection in a highly-nonlinear optical fiber. Generation of entangled photon pairs requires an understanding of the nonlinear and polarization effects in optical fibers and optimization of various parameters of pump laser and gain media. Single-photons are obtained by detecting one of the photons in an entangled photon pair and transmitting the other to the user. The fidelity of entangled photon pair is estimated by counting the actual and false counts in a coincidence counter. As the optical power of a single-photon is very low, photons are detected by gating an avalanche photodiode in the Geiger mode. I also discuss recent work with highly nonlinear fibre for coherent two-photon generation and squeezing with applications to quantum key distribution, fiber lasers, diffractive optical elements for beam shaping, using e-beam and possibly FIB, and MOEMS for beam steering and modulation. A majority of these techniques are of significant importance to the EGO project. Optical techniques being developed include coincidence counter, balanced homodyne detector, and electronics to support optical instrumentation.

The Photonics group at IIT Madras consists of 8 faculty, Masters and PhD students admitted through the M.S and PhD research programs. In addition, IITM has recently started a M.Tech program in Photonics. At IIT Kanpur, the Center for Laser Technology includes 12 faculty and M.Tech students. A PhD program devoted to multidisciplinary aspects of Lasers and Optics, starting from the year 2012 will is expected to provide additional manpower.

Finally, I talk about facilities available for fabrication of fibre-Bragg gratings, intergrated optical devices, Si-photonics and lithography. Additional facilities include Optical and RF spectrum analyzer, 40Gbps DQPSK modulator/demodulator, optical sampling oscilloscope (65GHz electrical) and 40Gbps PRBS generator.

Experiments with cold atoms in a Fabry Perot cavity in Ultra High Vacuum

Sadiq Rangwala
E-mail: sarangwala at rri.res.in
RRI, Bangalore, India

We present the atom cavity experiment in operation at the Raman Research Institute, Bangalore. In the talk we describe the experimental context in which the experiment is conceptualized. Following this we shall discuss the design and construction challenges that are presented by our physics goals. How we have overcome these instrumentation challenges shall then be addressed. The characterization and preliminary results from the atom cavity component of the experiments shall be presented. Some future technical and scientific problems/challenges on this experiment will then be stated and discussed. The emphasis of the talk will be more on the instrumentation and less on the physics.

Quantum optics and Quantum Information processing with cold atoms and Scanning probe microscopy

Umakant Rapol
E-mail: umakant.rapol at iiserpune.ac.in
IISER, Pune, India

In this talk I will briefly present the ongoing and future work in the �Atomic Physics and Quantum Optics Lab� and �Scanning probe microscopy Lab� of the Indian Institute of science education and research, Pune. The Atomic physics lab is involved in the experiments on development of novel platforms for distributed Quantum information processing. Distributed Quantum information deals with communication and transfer of Quantum information between two physical separated Quantum information processors. In our case the physically separated quantum systems are Isolated Atomic systems which will be confined to sub-wavelength volumes. The techniques that are going to be used are borrowed from the recent advances in the area of Plasmonics, where highly localized electric field strengths can be generated using Plasmons. Based on some reported calculations from other groups, it is possible to trap an individual atom in the near field and enhance the electromagnetic coupling between the atom and the field. This would enable generation of �Photon-on-demand� and transmit through low optical fibers to another atom physically away. In addition, tailored plasmonic structures would be explored to create 2-D lattices of Atoms with much smaller lattice spacing than that possible in traditional optical lattices. Currently, the lab has an experimental setup to cool Rb atoms down to sub-mK temperatures. These Atoms will be transferred in a Hybrid Magnetic trap - Optical trap combination and cooled further for future experiments.

The Scanning probe microscopy lab at IISER, Pune is involved in development of novel approaches towards measuring forces required to break bonds between single molecules. The other scientific goal of the group is to measure the mobility of liquid molecules under confinements of the order of molecular size itself. To achieve these goals, we have so far developed a precision distance sensor that is able to measure displacements of the order of an angstrom. The other development in the lab is to use micro-machined tuning-fork based methods to measure deflections in the similar range using stress generated in one of its arms.

Optics for GW detectors - in the context of IndIGO

Sendhil Raja
E-mail: sendhil at rrcat.gov.in
RRCAT, Indore, India

RRCAT being a member of the IndIGO Consortium, research and developmental work has been initiated in the Laser Instrumentation group for components and sub-systems related to Gravitation Wave Detectors (GWD). Activities being pursued during the XII Plan (during 2012-2017) are: Design and development of a 1W sub-khz line width laser for use in a high-resolution length calibrating interferometer with 1pm resolution, development of fabrication techniques such as ion beam figuring and Liquid jet polishing for fabricating Ultraflat optics for the interferometer and metrology techniques for measuring ultra-flat optics. The talk would give an overview of of the current optical Instrumentation activity of the group and detail upon the proposed components and sub-systems development in the coming years.

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