Hier findet ihr meine Veröffentlichungen in wissenschaftlichen Zeitschriften, meine Vorträge auf nationalen und internationalen wissenschaftlichen Konferenzen, sowie Outreach-Vorträge.
2021 |
Gerberding, Oliver; Isleif, Katharina-Sophie Ghost Beam Suppression in Deep Frequency Modulation Interferometry for Compact on-Axis Optical Heads Unveröffentlicht 2021. @unpublished{Gerberding2021, title = {Ghost Beam Suppression in Deep Frequency Modulation Interferometry for Compact on-Axis Optical Heads}, author = {Oliver Gerberding and Katharina-Sophie Isleif}, editor = {Sensors}, url = {https://www.preprints.org/manuscript/202102.0305/v1}, doi = {10.20944/preprints202102.0305.v1}, year = {2021}, date = {2021-02-10}, abstract = {We present a compact optical head design for wide-range and low noise displacement sensing using deep frequency modulation interferometry. The on-axis beam topology is realised in a quasi-monolithic component and relies on cube beamsplitters and beam transmission through perpendicular surfaces to keep angular alignment constant when operating in air or vacuum, which leads to the generation of ghost beams that can limit the phase readout linearity. We investigate the coupling of these beams into the non-linear phase readout scheme of DFMI and demonstrate adjustments of the phase estimation algorithm to reduce this effect. This is done through a combination of balanced detection and the inherent orthogonality of beat signals with different relative time-delays in deep frequency modulation interferometry that is a unique feature not available for heterodyne, quadrature or homodyne interferometry.}, keywords = {}, pubstate = {published}, tppubtype = {unpublished} } We present a compact optical head design for wide-range and low noise displacement sensing using deep frequency modulation interferometry. The on-axis beam topology is realised in a quasi-monolithic component and relies on cube beamsplitters and beam transmission through perpendicular surfaces to keep angular alignment constant when operating in air or vacuum, which leads to the generation of ghost beams that can limit the phase readout linearity. We investigate the coupling of these beams into the non-linear phase readout scheme of DFMI and demonstrate adjustments of the phase estimation algorithm to reduce this effect. This is done through a combination of balanced detection and the inherent orthogonality of beat signals with different relative time-delays in deep frequency modulation interferometry that is a unique feature not available for heterodyne, quadrature or homodyne interferometry. |
Ortiz, Diaz M; Gleason, J; Grote, H; Hallal, A; Hartman, M T; Hollis, H; Isleif, K S; James, A; Karan, K; Kozlowski, T; Lindner, A; Messineo, G; Mueller, G; Poeld, J H; Smith, R C G; Spector, A D; Tanner, D B; Wei, L -W; Willke, B Design of the ALPS II Optical System Unveröffentlicht 2021. @unpublished{Ortiz2021, title = {Design of the ALPS II Optical System}, author = {M. Diaz Ortiz and J. Gleason and H. Grote and A. Hallal and M. T. Hartman and H. Hollis and K. S. Isleif and A. James and K. Karan and T. Kozlowski and A. Lindner and G. Messineo and G. Mueller and J. H. Poeld and R. C. G. Smith and A. D. Spector and D. B. Tanner and L. -W. Wei and B. Willke}, editor = {Arxiv}, url = {https://arxiv.org/abs/2009.14294}, year = {2021}, date = {2021-02-07}, journal = {Arxiv}, keywords = {}, pubstate = {published}, tppubtype = {unpublished} } |
Collaboration, The LIGO Scientific; the Collaboration, Virgo; the Collaboration, KAGRA Upper Limits on the Isotropic Gravitational-Wave Background from Advanced LIGO's and Advanced Virgo's Third Observing Run Unveröffentlicht 2021. @unpublished{Collaboration2021, title = {Upper Limits on the Isotropic Gravitational-Wave Background from Advanced LIGO's and Advanced Virgo's Third Observing Run}, author = {The LIGO Scientific Collaboration and the Virgo Collaboration and the KAGRA Collaboration}, editor = {Arxiv}, url = {https://arxiv.org/abs/2101.12130}, year = {2021}, date = {2021-01-28}, journal = {Arxiv}, keywords = {}, pubstate = {published}, tppubtype = {unpublished} } |
Collaboration, The LIGO Scientific; the Collaboration, Virgo; the Collaboration, KAGRA Constraints on cosmic strings using data from the third Advanced LIGO-Virgo observing run Unveröffentlicht 2021. @unpublished{Collaboration2021b, title = {Constraints on cosmic strings using data from the third Advanced LIGO-Virgo observing run}, author = {The LIGO Scientific Collaboration and the Virgo Collaboration and the KAGRA Collaboration}, editor = {Arxiv}, url = {https://arxiv.org/abs/2101.12248}, year = {2021}, date = {2021-01-28}, journal = {Arxiv}, keywords = {}, pubstate = {published}, tppubtype = {unpublished} } |
2020 |
Meshksar, Neda; Mehmet, Moritz; Isleif, Katharina-Sophie; Heinzel, Gerhard Sensors, 21(1) , 2020. @article{Meshksar2020, title = {Applying Differential Wave-Front Sensing and Differential Power Sensing for Simultaneous Precise and Wide-Range Test-Mass Rotation Measurements}, author = {Neda Meshksar and Moritz Mehmet and Katharina-Sophie Isleif and Gerhard Heinzel}, url = {https://doi.org/10.3390/s21010164}, year = {2020}, date = {2020-12-29}, journal = {Sensors}, volume = {21(1)}, abstract = {We propose to combine differential wave-front sensing (DWS) and differential power sensing (DPS) in a Mach-Zehnder type interferometer for measuring the rotational dynamics of a test-mass. Using the DWS method, a high sensitive measurement of 6 nrad Hz−1/2 in sub-Hz frequencies can be provided around the test-mass nominal position (±0.11 mrad), whereas the measurement of a wide rotation range (±5 mrad) is realized by the DPS method. The interferometer can be combined with deep frequency modulation (DFM) interferometry for measurement of the test-mass translational dynamics. The setup and the resulting interferometric signals are verified by simulations. An optimization algorithm is applied to find suitable positions of the lenses and the waist size of the input laser in order to determine the best trade of between the slope of DWS, dynamic range of DPS, and the interferometric contrast. Our simulation further allows to investigate the layout for robustness and design tolerances. We compare our device with a recent experimental realization of a DFM interferometer and find that a practical implementation of the interferometer proposed here has the potential to provide translational and rotational test-mass tracking with state-of-the-art sensitivity. The simple and compact design, and especially the capability of sensing the test-mass rotation in a wide range and simultaneously providing a high-precision measurement close to the test-mass nominal position makes the design especially suitable for example for employment in torsion pendulum setups.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We propose to combine differential wave-front sensing (DWS) and differential power sensing (DPS) in a Mach-Zehnder type interferometer for measuring the rotational dynamics of a test-mass. Using the DWS method, a high sensitive measurement of 6 nrad Hz−1/2 in sub-Hz frequencies can be provided around the test-mass nominal position (±0.11 mrad), whereas the measurement of a wide rotation range (±5 mrad) is realized by the DPS method. The interferometer can be combined with deep frequency modulation (DFM) interferometry for measurement of the test-mass translational dynamics. The setup and the resulting interferometric signals are verified by simulations. An optimization algorithm is applied to find suitable positions of the lenses and the waist size of the input laser in order to determine the best trade of between the slope of DWS, dynamic range of DPS, and the interferometric contrast. Our simulation further allows to investigate the layout for robustness and design tolerances. We compare our device with a recent experimental realization of a DFM interferometer and find that a practical implementation of the interferometer proposed here has the potential to provide translational and rotational test-mass tracking with state-of-the-art sensitivity. The simple and compact design, and especially the capability of sensing the test-mass rotation in a wide range and simultaneously providing a high-precision measurement close to the test-mass nominal position makes the design especially suitable for example for employment in torsion pendulum setups. |
Collaboration, The LIGO Scientific; the Collaboration, Virgo; the Collaboration, KAGRA Diving below the spin-down limit: Constraints on gravitational waves from the energetic young pulsar PSR J0537-6910 Unveröffentlicht 2020. @unpublished{Collaboration2020b, title = {Diving below the spin-down limit: Constraints on gravitational waves from the energetic young pulsar PSR J0537-6910}, author = {The LIGO Scientific Collaboration and the Virgo Collaboration and the KAGRA Collaboration}, editor = {Arxiv}, url = {https://arxiv.org/abs/2012.12926}, year = {2020}, date = {2020-12-23}, journal = {Arxiv}, keywords = {}, pubstate = {published}, tppubtype = {unpublished} } |
Collaboration, The LIGO Scientific; the Collaboration, Virgo All-sky search in early O3 LIGO data for continuous gravitational-wave signals from unknown neutron stars in binary systems Unveröffentlicht 2020. @unpublished{Collaboration2020, title = {All-sky search in early O3 LIGO data for continuous gravitational-wave signals from unknown neutron stars in binary systems}, author = {The LIGO Scientific Collaboration and the Virgo Collaboration}, editor = {Arxiv}, url = {https://arxiv.org/abs/2012.12128}, year = {2020}, date = {2020-12-22}, journal = {Arxiv}, keywords = {}, pubstate = {published}, tppubtype = {unpublished} } |
Isleif, Katharina-Sophie; collaboration ALPS, Virtual Lab Tour - ALPS Vortrag 05.11.2020, (Physikerinnentagung 2020, Hamburg). @misc{Isleif2020b, title = {Virtual Lab Tour - ALPS}, author = {Katharina-Sophie Isleif and collaboration ALPS}, year = {2020}, date = {2020-11-05}, abstract = {Virtuelle Labortour durch die HERA-Tunnel West: Mittels optischer Technologien der Gravitationswellendetektoren sollen mit dem Hochpräzision-Experiment „ALPSII" Axion-ähnliche Teilchen am DESY nachgewiesen werden.}, note = {Physikerinnentagung 2020, Hamburg}, keywords = {}, pubstate = {published}, tppubtype = {presentation} } Virtuelle Labortour durch die HERA-Tunnel West: Mittels optischer Technologien der Gravitationswellendetektoren sollen mit dem Hochpräzision-Experiment „ALPSII" Axion-ähnliche Teilchen am DESY nachgewiesen werden. |
Isleif, Katharina-Sophie ALPS II: Any light particle search Vortrag 28.04.2020, (Quantum Universe Day, Cluster of Excellence, University of Hamburg & DESY). @misc{Isleif2020, title = {ALPS II: Any light particle search }, author = {Katharina-Sophie Isleif }, year = {2020}, date = {2020-04-28}, note = {Quantum Universe Day, Cluster of Excellence, University of Hamburg & DESY}, keywords = {}, pubstate = {published}, tppubtype = {presentation} } |
2019 |
Isleif, Katharina-Sophie; Heinzel, Gerhard; Mehmet, Moritz; Gerberding, Oliver Compact Multifringe Interferometry with Subpicometer Precision Artikel Phys. Rev. Applied, 12 , S. 034025, 2019. @article{Isleif2019, title = {Compact Multifringe Interferometry with Subpicometer Precision}, author = {Katharina-Sophie Isleif and Gerhard Heinzel and Moritz Mehmet and Oliver Gerberding}, doi = {10.1103/PhysRevApplied.12.034025}, year = {2019}, date = {2019-09-01}, journal = {Phys. Rev. Applied}, volume = {12}, pages = {034025}, publisher = {American Physical Society}, abstract = {Deep-frequency-modulation interferometry combines optical minimalism with multifringe readout. However, precision is key for applications such as optical gradiometers for satellite geodesy or as dimensional sensors for ground-based gravity experiments. We present a single-component interferometer smaller than a cubic inch. Two of these are compared to each other to demonstrate tilt and displacement measurements with a precision of less than 20 nrad/√Hz and 1 pm/√Hz at frequencies below 1 Hz.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Deep-frequency-modulation interferometry combines optical minimalism with multifringe readout. However, precision is key for applications such as optical gradiometers for satellite geodesy or as dimensional sensors for ground-based gravity experiments. We present a single-component interferometer smaller than a cubic inch. Two of these are compared to each other to demonstrate tilt and displacement measurements with a precision of less than 20 nrad/√Hz and 1 pm/√Hz at frequencies below 1 Hz. |
Isleif, Katharina-Sophie Outreach Talk: Gravitationswellen Vortrag 01.09.2019, (Outreach Talk for Students, In the context of the Cluster "Quantum Universe" of the University of Hamburg). @misc{outreachIsleif, title = {Outreach Talk: Gravitationswellen}, author = {Katharina-Sophie Isleif }, url = {https://katharinasophieisleif.net/wp-content/uploads/2020/07/20200104_GW_outreach.pdf}, year = {2019}, date = {2019-09-01}, note = {Outreach Talk for Students, In the context of the Cluster "Quantum Universe" of the University of Hamburg}, keywords = {}, pubstate = {published}, tppubtype = {presentation} } |
2018 |
Isleif, Katharina-Sophie Laser interferometry for LISA & satellite geodesy missions Vortrag 16.05.2018, (PhD defense at the Leibniz Universität Hannover, Max Planck Institute for Gravitational Physics (Albert Einstein Institute), Germany). @misc{Isleif2018, title = {Laser interferometry for LISA & satellite geodesy missions}, author = {Katharina-Sophie Isleif }, year = {2018}, date = {2018-05-16}, note = {PhD defense at the Leibniz Universität Hannover, Max Planck Institute for Gravitational Physics (Albert Einstein Institute), Germany}, keywords = {}, pubstate = {published}, tppubtype = {presentation} } |
Isleif, Katharina-Sophie; Bischof, Lea; Ast, Stefan; Penkert, Daniel; Schwarze, Thomas S; á, Germán Fern; Zwetz, Max; Veith, Sonja; Hennig, Jan-Simon; Tröbs, Michael; Reiche, Jens; Gerberding, Oliver; Danzmann, Karsten; Heinzel, Gerhard Classical and Quantum Gravity, 35 (8), S. 085009, 2018. @article{Isleif_2018, title = {Towards the LISA backlink: experiment design for comparing optical phase reference distribution systems}, author = {Katharina-Sophie Isleif and Lea Bischof and Stefan Ast and Daniel Penkert and Thomas S Schwarze and Germán Fern á and Max Zwetz and Sonja Veith and Jan-Simon Hennig and Michael Tröbs and Jens Reiche and Oliver Gerberding and Karsten Danzmann and Gerhard Heinzel}, doi = {10.1088/1361-6382/aaa879}, year = {2018}, date = {2018-03-01}, journal = {Classical and Quantum Gravity}, volume = {35}, number = {8}, pages = {085009}, publisher = {IOP Publishing}, abstract = {LISA is a proposed space-based laser interferometer detecting gravitational waves by measuring distances between free-floating test masses housed in three satellites in a triangular constellation with laser links in-between. Each satellite contains two optical benches that are articulated by moving optical subassemblies for compensating the breathing angle in the constellation. The phase reference distribution system, also known as backlink, forms an optical bi-directional path between the intra-satellite benches. In this work we discuss phase reference implementations with a target non-reciprocity of at most μrad , equivalent to 1 pm for a wavelength of 1064 nm in the frequency band from 0.1 mHz to 1 Hz. One phase reference uses a steered free beam connection, the other one a fiber together with additional laser frequencies. The noise characteristics of these implementations will be compared in a single interferometric set-up with a previously successfully tested direct fiber connection. We show the design of this interferometer created by optical simulations including ghost beam analysis, component alignment and noise estimation. First experimental results of a free beam laser link between two optical set-ups that are co-rotating by ±1° are presented. This experiment demonstrates sufficient thermal stability during rotation of less than 10−4 K at 1 mHz and operation of the free beam steering mirror control over more than 1 week.}, keywords = {}, pubstate = {published}, tppubtype = {article} } LISA is a proposed space-based laser interferometer detecting gravitational waves by measuring distances between free-floating test masses housed in three satellites in a triangular constellation with laser links in-between. Each satellite contains two optical benches that are articulated by moving optical subassemblies for compensating the breathing angle in the constellation. The phase reference distribution system, also known as backlink, forms an optical bi-directional path between the intra-satellite benches. In this work we discuss phase reference implementations with a target non-reciprocity of at most μrad , equivalent to 1 pm for a wavelength of 1064 nm in the frequency band from 0.1 mHz to 1 Hz. One phase reference uses a steered free beam connection, the other one a fiber together with additional laser frequencies. The noise characteristics of these implementations will be compared in a single interferometric set-up with a previously successfully tested direct fiber connection. We show the design of this interferometer created by optical simulations including ghost beam analysis, component alignment and noise estimation. First experimental results of a free beam laser link between two optical set-ups that are co-rotating by ±1° are presented. This experiment demonstrates sufficient thermal stability during rotation of less than 10−4 K at 1 mHz and operation of the free beam steering mirror control over more than 1 week. |
Isleif, Katharina-Sophie Laser interferometry for LISA and satellite geodesy missions Promotionsarbeit Dissertation, Gottfried Wilhelm Leibniz Universität Hannover, 2018. @phdthesis{TIBKAT:1030356750, title = {Laser interferometry for LISA and satellite geodesy missions}, author = {Katharina-Sophie Isleif}, editor = {Karsten Danzmann and Gerhard Heinzel and Guido Müller}, url = {https://www.tib.eu/de/suchen/id/TIBKAT%3A1030356750}, doi = {10.15488/3526}, year = {2018}, date = {2018-01-01}, publisher = {Gottfried Wilhelm Leibniz Universität Hannover;}, address = {Hannover}, school = {Dissertation, Gottfried Wilhelm Leibniz Universität Hannover}, abstract = {The development and investigation of laser interferometry concepts for performing precise length measurements at frequencies below 1Hz is the main topic of this thesis. These concepts are quintessential for space-based measurements of gravitational waves or the Earth gravity field. For the Laser Interferometer Space Antenna (LISA) and future satellite geodesy missions, various interferometer types have been studied between 2014 and 2018 at the Albert Einstein Institute (AEI) in Hannover as a part of the work presented here. The first part of this thesis presents conceptual design studies of phase reference distribution systems (PRDSs) for LISA. The usage of Telescope Pointing is the baseline mechanism for the current LISA design and implies the need for a light-exchanging backlink connection between two rotating optical benches within one satellite. Different backlink implementations are presented and analyzed, the final choice however remains one of the last open questions for the LISA optical metrology. A test-bed for comparing three backlinks with each other in a single, so-called Three-Backlink interferometer (TBI) experiment, has been simulated and a detailed noise estimation, including a critical stray light analysis, is presented. A free-beam connection between two moving set-ups was established by which the full functionality of the experimental environment was validated. The design of the TBI has been completed and the experiment, consisting of two rotating quasi-monolithic optical benches, is currently under construction. The full experiment will enable to test the performance of LISA backlink candidates with a precision of 1 pm/√Hz in a relevant environment. The second part of this thesis describes alternative interferometer techniques for reducing the complexity of optical set-ups, while modern digital signal processing is applied for recovering the desired phase information. The simplifications in the optical part enables multi-channel operation and multi-degree of freedom readout, which is required for future gradiometers in satellites consisting of six or more test masses. An experiment simulating such a test mass readout with only a single optical component has been established. Interferometric readout noise levels of 1.0pm/√Hz at 100mHz were achieved by using deep frequency modulation interferometry (DFMI), a novel technique developed as part of this thesis.}, type = {phd thesis}, keywords = {}, pubstate = {published}, tppubtype = {phdthesis} } The development and investigation of laser interferometry concepts for performing precise length measurements at frequencies below 1Hz is the main topic of this thesis. These concepts are quintessential for space-based measurements of gravitational waves or the Earth gravity field. For the Laser Interferometer Space Antenna (LISA) and future satellite geodesy missions, various interferometer types have been studied between 2014 and 2018 at the Albert Einstein Institute (AEI) in Hannover as a part of the work presented here. The first part of this thesis presents conceptual design studies of phase reference distribution systems (PRDSs) for LISA. The usage of Telescope Pointing is the baseline mechanism for the current LISA design and implies the need for a light-exchanging backlink connection between two rotating optical benches within one satellite. Different backlink implementations are presented and analyzed, the final choice however remains one of the last open questions for the LISA optical metrology. A test-bed for comparing three backlinks with each other in a single, so-called Three-Backlink interferometer (TBI) experiment, has been simulated and a detailed noise estimation, including a critical stray light analysis, is presented. A free-beam connection between two moving set-ups was established by which the full functionality of the experimental environment was validated. The design of the TBI has been completed and the experiment, consisting of two rotating quasi-monolithic optical benches, is currently under construction. The full experiment will enable to test the performance of LISA backlink candidates with a precision of 1 pm/√Hz in a relevant environment. The second part of this thesis describes alternative interferometer techniques for reducing the complexity of optical set-ups, while modern digital signal processing is applied for recovering the desired phase information. The simplifications in the optical part enables multi-channel operation and multi-degree of freedom readout, which is required for future gradiometers in satellites consisting of six or more test masses. An experiment simulating such a test mass readout with only a single optical component has been established. Interferometric readout noise levels of 1.0pm/√Hz at 100mHz were achieved by using deep frequency modulation interferometry (DFMI), a novel technique developed as part of this thesis. |
2017 |
Isleif, Katharina-Sophie Advanced optics for space interferometry Vortrag 30.08.2017, (Evaluation of the International Max Planck Research School (IMPRS), Max Planck Institute for Gravitational Physics (Albert Einstein Institute), Germany). @misc{Isleif2017, title = {Advanced optics for space interferometry}, author = {Katharina-Sophie Isleif }, year = {2017}, date = {2017-08-30}, note = {Evaluation of the International Max Planck Research School (IMPRS), Max Planck Institute for Gravitational Physics (Albert Einstein Institute), Germany}, keywords = {}, pubstate = {published}, tppubtype = {presentation} } |
Isleif, Katharina-Sophie Upscalable optical test mass readout via deep frequency modulation interferometry Vortrag 14.07.2017, (12th Edoardo Amaldi Conference, Pasadena, Kalifornien, USA). @misc{Isleif2017b, title = {Upscalable optical test mass readout via deep frequency modulation interferometry}, author = {Katharina-Sophie Isleif }, year = {2017}, date = {2017-07-14}, note = {12th Edoardo Amaldi Conference, Pasadena, Kalifornien, USA}, keywords = {}, pubstate = {published}, tppubtype = {presentation} } |
Isleif, K-S; Gerberding, O; Penkert, D; Fitzsimons, E; Ward, H; Robertson, D; Livas, J; Mueller, G; Reiche, J; Heinzel, G; Danzmann, K Suppressing ghost beams: Backlink options for LISA Konferenzbericht IOP Publishing, 840 , 2017. @proceedings{Isleif_2017, title = {Suppressing ghost beams: Backlink options for LISA}, author = {K-S Isleif and O Gerberding and D Penkert and E Fitzsimons and H Ward and D Robertson and J Livas and G Mueller and J Reiche and G Heinzel and K Danzmann}, url = {https://doi.org/10.1088%2F1742-6596%2F840%2F1%2F012016}, doi = {10.1088/1742-6596/840/1/012016}, year = {2017}, date = {2017-05-01}, journal = {Journal of Physics: Conference Series}, volume = {840}, pages = {012016}, publisher = {IOP Publishing}, abstract = {In this article we discuss possible design options for the optical phase reference system, the so called backlink, between two moving optical benches in a LISA satellite. The candidates are based on two approaches: Fiber backlinks, with additional features like mode cleaning cavities and Faraday isolators, and free beam backlinks with angle compensation techniques. We will indicate dedicated ghost beam mitigation strategies for the design options and we will point out critical aspects in case of an implementation in LISA.}, keywords = {}, pubstate = {published}, tppubtype = {proceedings} } In this article we discuss possible design options for the optical phase reference system, the so called backlink, between two moving optical benches in a LISA satellite. The candidates are based on two approaches: Fiber backlinks, with additional features like mode cleaning cavities and Faraday isolators, and free beam backlinks with angle compensation techniques. We will indicate dedicated ghost beam mitigation strategies for the design options and we will point out critical aspects in case of an implementation in LISA. |
Gerberding, Oliver; Isleif, Katharina-Sophie; Mehmet, Moritz; Danzmann, Karsten; Heinzel, Gerhard Phys. Rev. Applied, 7 , S. 024027, 2017. @article{PhysRevApplied.7.024027, title = {Laser-Frequency Stabilization via a Quasimonolithic Mach-Zehnder Interferometer with Arms of Unequal Length and Balanced dc Readout}, author = {Oliver Gerberding and Katharina-Sophie Isleif and Moritz Mehmet and Karsten Danzmann and Gerhard Heinzel}, url = {https://link.aps.org/doi/10.1103/PhysRevApplied.7.024027}, doi = {10.1103/PhysRevApplied.7.024027}, year = {2017}, date = {2017-02-01}, journal = {Phys. Rev. Applied}, volume = {7}, pages = {024027}, publisher = {American Physical Society}, abstract = {Low-frequency high-precision laser interferometry is subject to excess laser-frequency-noise coupling via arm-length differences which is commonly mitigated by locking the frequency to a stable reference system. This approach is crucial to achieve picometer-level sensitivities in the 0.1-mHz to 1-Hz regime, where laser-frequency noise is usually high and couples into the measurement phase via arm-length mismatches in the interferometers. Here we describe the results achieved by frequency stabilizing an external cavity diode laser to a quasimonolithic unequal arm-length Mach-Zehnder interferometer readout at midfringe via balanced detection. We find this stabilization scheme to be an elegant solution combining a minimal number of optical components, no additional laser modulations, and relatively low-frequency-noise levels. The Mach-Zehnder interferometer is designed and constructed to minimize the influence of thermal couplings and to reduce undesired stray light using the optical simulation tool ifocad. We achieve frequency-noise levels below 100Hz/√Hz at 1 Hz and are able to demonstrate the LISA frequency prestabilization requirement of 300 Hz/√Hz down to frequencies of 100 mHz by beating the stabilized laser with an iodine-locked reference.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Low-frequency high-precision laser interferometry is subject to excess laser-frequency-noise coupling via arm-length differences which is commonly mitigated by locking the frequency to a stable reference system. This approach is crucial to achieve picometer-level sensitivities in the 0.1-mHz to 1-Hz regime, where laser-frequency noise is usually high and couples into the measurement phase via arm-length mismatches in the interferometers. Here we describe the results achieved by frequency stabilizing an external cavity diode laser to a quasimonolithic unequal arm-length Mach-Zehnder interferometer readout at midfringe via balanced detection. We find this stabilization scheme to be an elegant solution combining a minimal number of optical components, no additional laser modulations, and relatively low-frequency-noise levels. The Mach-Zehnder interferometer is designed and constructed to minimize the influence of thermal couplings and to reduce undesired stray light using the optical simulation tool ifocad. We achieve frequency-noise levels below 100Hz/√Hz at 1 Hz and are able to demonstrate the LISA frequency prestabilization requirement of 300 Hz/√Hz down to frequencies of 100 mHz by beating the stabilized laser with an iodine-locked reference. |
2016 |
Isleif, Katharina-Sophie The LISA backlink - Comparing optical phase reference systems Vortrag 06.09.2016, (LISA Symposium, ETH, Zurich, Switzerland). @misc{Isleif2016b, title = {The LISA backlink - Comparing optical phase reference systems}, author = {Katharina-Sophie Isleif }, year = {2016}, date = {2016-09-06}, note = {LISA Symposium, ETH, Zurich, Switzerland}, keywords = {}, pubstate = {published}, tppubtype = {presentation} } |
Isleif, Katharina-Sophie; Gerberding, Oliver; Mehmet, Moritz; Schwarze, Thomas S; Heinzel, Gerhard; Danzmann, Karsten Comparing interferometry techniques for multi-degree of freedom test mass readout Konferenzbericht IOP Publishing, 716 , 2016. @proceedings{Isleif_2016, title = {Comparing interferometry techniques for multi-degree of freedom test mass readout}, author = {Katharina-Sophie Isleif and Oliver Gerberding and Moritz Mehmet and Thomas S Schwarze and Gerhard Heinzel and Karsten Danzmann}, url = {https://doi.org/10.1088%2F1742-6596%2F716%2F1%2F012008}, doi = {10.1088/1742-6596/716/1/012008}, year = {2016}, date = {2016-05-01}, journal = {Journal of Physics: Conference Series}, volume = {716}, pages = {012008}, publisher = {IOP Publishing}, abstract = {Laser interferometric readout systems with 1pm/Hz precision over long time scales have successfully been developed for LISA and LISA Pathfinder. Future gravitational physics experiments, for example in the fields of gravitational wave detection and geodesy, will potentially require similar levels of displacement and tilt readouts of multiple test masses in multiple degrees of freedom. In this article we compare currently available classic interferometry schemes with new techniques using phase modulations and complex readout algorithms. Based on a simple example we show that the new techniques have great potential to simplify interferometric readouts.}, keywords = {}, pubstate = {published}, tppubtype = {proceedings} } Laser interferometric readout systems with 1pm/Hz precision over long time scales have successfully been developed for LISA and LISA Pathfinder. Future gravitational physics experiments, for example in the fields of gravitational wave detection and geodesy, will potentially require similar levels of displacement and tilt readouts of multiple test masses in multiple degrees of freedom. In this article we compare currently available classic interferometry schemes with new techniques using phase modulations and complex readout algorithms. Based on a simple example we show that the new techniques have great potential to simplify interferometric readouts. |
Lieser, Maike; Fitzsimons, E; Isleif, K-S; Killow, C; Perreur-Lloyd, M; Robertson, D; Schuster, S; Tröbs, M; Veith, S; Ward, H; Heinzel, G; Danzmann, K Construction of an optical test-bed for eLISA Konferenzbericht IOP Publishing, 716 , 2016. @proceedings{Lieser_2016, title = {Construction of an optical test-bed for eLISA}, author = {Maike Lieser and E Fitzsimons and K-S Isleif and C Killow and M Perreur-Lloyd and D Robertson and S Schuster and M Tröbs and S Veith and H Ward and G Heinzel and K Danzmann}, url = {https://doi.org/10.1088%2F1742-6596%2F716%2F1%2F012029}, doi = {10.1088/1742-6596/716/1/012029}, year = {2016}, date = {2016-05-01}, journal = {Journal of Physics: Conference Series}, volume = {716}, pages = {012029}, publisher = {IOP Publishing}, abstract = {In the planned eLISA mission a key part of the system is the optical bench that holds the interferometers for reading out the inter-spacecraft distance and the test mass position. We report on ongoing technology development for the eLISA optical system like the back-link between the optical benches and the science interferometer where the local beam is interfered with the received beam from the distant spacecraft. The focus will be on a setup to investigate the tilt-to-pathlength coupling in the science interferometer. To test the science interferometer in the lab a second bench providing a laser beam and a reference interferometer is needed. We present a setup with two ultra-stable low expansion glass benches and bonded optics. To suppress the tilt-to-pathlength coupling to the required level (few μm/rad) imaging optics are placed in front of the interferometer photo diodes.}, keywords = {}, pubstate = {published}, tppubtype = {proceedings} } In the planned eLISA mission a key part of the system is the optical bench that holds the interferometers for reading out the inter-spacecraft distance and the test mass position. We report on ongoing technology development for the eLISA optical system like the back-link between the optical benches and the science interferometer where the local beam is interfered with the received beam from the distant spacecraft. The focus will be on a setup to investigate the tilt-to-pathlength coupling in the science interferometer. To test the science interferometer in the lab a second bench providing a laser beam and a reference interferometer is needed. We present a setup with two ultra-stable low expansion glass benches and bonded optics. To suppress the tilt-to-pathlength coupling to the required level (few μm/rad) imaging optics are placed in front of the interferometer photo diodes. |
Isleif, Katharina-Sophie The journey to noise reduced and ultra stable interferometers Vortrag 01.03.2016, (Deutsch-Physikalische-Gesellschaft Frühjahrestagung, Hannover, Germany). @misc{Isleif2016c, title = {The journey to noise reduced and ultra stable interferometers}, author = {Katharina-Sophie Isleif}, year = {2016}, date = {2016-03-01}, abstract = {Laser interferometry achieving pm/$\sqrt{\mathrm{Hz}}$ sensitivities in the mHz-frequency range is the key technology for satellite missions in the area of gravitational wave detection and geodesy, but it requires sophisticated interferometer layouts that suppress classical interferometer noise sources like scattered light, ghost beams, laser frequency noise and misalignments just by design. We present the recipe for a successful low-noise interferometer construction, starting with a digital design of the interferometer using the C++ library IfoCad, followed by an optimisation in which we are looking at the simulated interferometer data. Different optimisation parameters, like the overall interferometer architecture, the usage of wedged components and the correct positions, are discussed on the basis of two examples: A Mach-Zehnder interferometer used for the test mass readout in future geodesy missions via deep frequency modulation interferometry, and the 3-Backlink-Setup, an experiment for the laser interferometer space antenna (LISA). The interferometer construction combines the manufacture of a template, a thermally stable quasi-monolithic assembly of the components and a Coordinate Measuring Machine. We compare the simulation with a setup assembled by hand and an optimally designed interferometer.}, note = {Deutsch-Physikalische-Gesellschaft Frühjahrestagung, Hannover, Germany}, keywords = {}, pubstate = {published}, tppubtype = {presentation} } Laser interferometry achieving pm/$sqrt{mathrm{Hz}}$ sensitivities in the mHz-frequency range is the key technology for satellite missions in the area of gravitational wave detection and geodesy, but it requires sophisticated interferometer layouts that suppress classical interferometer noise sources like scattered light, ghost beams, laser frequency noise and misalignments just by design. We present the recipe for a successful low-noise interferometer construction, starting with a digital design of the interferometer using the C++ library IfoCad, followed by an optimisation in which we are looking at the simulated interferometer data. Different optimisation parameters, like the overall interferometer architecture, the usage of wedged components and the correct positions, are discussed on the basis of two examples: A Mach-Zehnder interferometer used for the test mass readout in future geodesy missions via deep frequency modulation interferometry, and the 3-Backlink-Setup, an experiment for the laser interferometer space antenna (LISA). The interferometer construction combines the manufacture of a template, a thermally stable quasi-monolithic assembly of the components and a Coordinate Measuring Machine. We compare the simulation with a setup assembled by hand and an optimally designed interferometer. |
Isleif, Katharina-Sophie; Gerberding, Oliver; Schwarze, Thomas S; Mehmet, Moritz; Heinzel, Gerhard; Cervantes, Felipe Guzmán Experimental demonstration of deep frequency modulation interferometry Artikel Optics Express, 24 (2), S. 1676–1684, 2016. @article{isleif2016experimental, title = {Experimental demonstration of deep frequency modulation interferometry}, author = {Katharina-Sophie Isleif and Oliver Gerberding and Thomas S Schwarze and Moritz Mehmet and Gerhard Heinzel and Felipe Guzmán Cervantes}, url = {https://www.osapublishing.org/oe/abstract.cfm?uri=oe-24-2-1676}, doi = {10.1364/OE.24.001676}, year = {2016}, date = {2016-01-01}, journal = {Optics Express}, volume = {24}, number = {2}, pages = {1676--1684}, publisher = {Optical Society of America}, abstract = {Experiments for space and ground-based gravitational wave detectors often require a large dynamic range interferometric position readout of test masses with 1 pm/√Hz precision over long time scales. Heterodyne interferometer schemes that achieve such precisions are available, but they require complex optical set-ups, limiting their scalability for multiple channels. This article presents the first experimental results on deep frequency modulation interferometry, a new technique that combines sinusoidal laser frequency modulation in unequal arm length interferometers with a non-linear fit algorithm. We have tested the technique in a Michelson and a Mach-Zehnder Interferometer topology, respectively, demonstrated continuous phase tracking of a moving mirror and achieved a performance equivalent to a displacement sensitivity of 250 pm/√Hz at 1 mHz between the phase measurements of two photodetectors monitoring the same optical signal. By performing time series fitting of the extracted interference signals, we measured that the linearity of the laser frequency modulation is on the order of 2% for the laser source used.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Experiments for space and ground-based gravitational wave detectors often require a large dynamic range interferometric position readout of test masses with 1 pm/√Hz precision over long time scales. Heterodyne interferometer schemes that achieve such precisions are available, but they require complex optical set-ups, limiting their scalability for multiple channels. This article presents the first experimental results on deep frequency modulation interferometry, a new technique that combines sinusoidal laser frequency modulation in unequal arm length interferometers with a non-linear fit algorithm. We have tested the technique in a Michelson and a Mach-Zehnder Interferometer topology, respectively, demonstrated continuous phase tracking of a moving mirror and achieved a performance equivalent to a displacement sensitivity of 250 pm/√Hz at 1 mHz between the phase measurements of two photodetectors monitoring the same optical signal. By performing time series fitting of the extracted interference signals, we measured that the linearity of the laser frequency modulation is on the order of 2% for the laser source used. |
2015 |
Isleif, Katharina-Sophie Phase modulation techniques for multi-fringe interferometry Vortrag 22.06.2015, (11th Edoardo Amaldi Conference, Gwangju, South Corea). @misc{Isleif2015, title = {Phase modulation techniques for multi-fringe interferometry}, author = {Katharina-Sophie Isleif }, year = {2015}, date = {2015-06-22}, abstract = {Experiments for space and ground-based gravitational wave detectors often require large dynamic range interferometric position readout of test masses with pm/sqrtHz precision over long time scales. Heterodyne interferometer schemes that achieve such precisions are available, but they require complex optical set-ups, which limits their scalability for multiple channels. We discuss alternative interferometer techniques that were investigated in recent years, which use phase modulation schemes and complex digital readout algorithms to decrease the complexity of optical set-ups. As highlight we present the first experimental results on deep frequency modulation, a new technique that combines sinusoidial laser frequency modulation in unequal arm-length interferometers with a non-linear fit of the amplitudes of the modulation frequency harmonics, an algorithm first developed for deep phase modulation. This scheme requires very few optical components in the phase critical beam path and promises simple scalability for future multi-degree of freedom readouts of test masses.}, note = {11th Edoardo Amaldi Conference, Gwangju, South Corea}, keywords = {}, pubstate = {published}, tppubtype = {presentation} } Experiments for space and ground-based gravitational wave detectors often require large dynamic range interferometric position readout of test masses with pm/sqrtHz precision over long time scales. Heterodyne interferometer schemes that achieve such precisions are available, but they require complex optical set-ups, which limits their scalability for multiple channels.
We discuss alternative interferometer techniques that were investigated in recent years, which use phase modulation schemes and complex digital readout algorithms to decrease the complexity of optical set-ups.
As highlight we present the first experimental results on deep frequency modulation, a new technique that combines sinusoidial laser frequency modulation in unequal arm-length interferometers with a non-linear fit of the amplitudes of the modulation frequency harmonics, an algorithm first developed for deep phase modulation.
This scheme requires very few optical components in the phase critical beam path and promises simple scalability for future multi-degree of freedom readouts of test masses. |
2014 |
Isleif, Katharina-S; Gerberding, Oliver; Köhlenbeck, Sina; Sutton, Andrew; Sheard, Benjamin; Goßler, Stefan; Shaddock, Daniel; Heinzel, Gerhard; Danzmann, Karsten Highspeed multiplexed heterodyne interferometry Artikel Optics express, 22 (20), S. 24689–24696, 2014. @article{isleif2014highspeed, title = {Highspeed multiplexed heterodyne interferometry}, author = {Katharina-S Isleif and Oliver Gerberding and Sina Köhlenbeck and Andrew Sutton and Benjamin Sheard and Stefan Goßler and Daniel Shaddock and Gerhard Heinzel and Karsten Danzmann}, url = {https://www.osapublishing.org/oe/abstract.cfm?uri=oe-22-20-24689}, doi = {10.1364/OE.22.024689}, year = {2014}, date = {2014-01-01}, journal = {Optics express}, volume = {22}, number = {20}, pages = {24689--24696}, publisher = {Optical Society of America}, abstract = {Digitally enhanced heterodyne interferometry is a metrology technique that uses pseudo-random noise codes for modulating the phase of the laser light. Multiple interferometric signals from the same beam path can thereby be isolated based on their propagation delay, allowing one to use advantageous optical layouts in comparison to classic laser interferometers. We present here a high speed version of this technique for measuring multiple targets spatially separated by only a few centimetres. This allows measurements of multiplexed signals using free beams, making the technique attractive for several applications requiring compact optical set-ups like for example space-based interferometers. In an experiment using a modulation and sampling rate of 1.25 GHz we are able to demonstrate multiplexing between targets only separated by 36 cm and we achieve a displacement measurement noise floor of <3 pm/√Hz at 10 Hz between them. We identify a limiting excess noise at low frequencies which is unique to this technique and is probably caused by the finite bandwidth in our measurement set-up. Utilising an active clock jitter correction scheme we are also able to reduce this noise in a null measurement configuration by one order of magnitude.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Digitally enhanced heterodyne interferometry is a metrology technique that uses pseudo-random noise codes for modulating the phase of the laser light. Multiple interferometric signals from the same beam path can thereby be isolated based on their propagation delay, allowing one to use advantageous optical layouts in comparison to classic laser interferometers. We present here a high speed version of this technique for measuring multiple targets spatially separated by only a few centimetres. This allows measurements of multiplexed signals using free beams, making the technique attractive for several applications requiring compact optical set-ups like for example space-based interferometers. In an experiment using a modulation and sampling rate of 1.25 GHz we are able to demonstrate multiplexing between targets only separated by 36 cm and we achieve a displacement measurement noise floor of <3 pm/√Hz at 10 Hz between them. We identify a limiting excess noise at low frequencies which is unique to this technique and is probably caused by the finite bandwidth in our measurement set-up. Utilising an active clock jitter correction scheme we are also able to reduce this noise in a null measurement configuration by one order of magnitude. |
2013 |
Isleif, Katharina-Sophie Digitally enhanced heterodyne interferometry Vortrag 15.03.2013, (Deutsch-Physikalische-Gesellschaft Frühjahrestagung, Hannover, Germany). @misc{Isleif2013, title = {Digitally enhanced heterodyne interferometry}, author = {Katharina-Sophie Isleif }, year = {2013}, date = {2013-03-15}, note = {Deutsch-Physikalische-Gesellschaft Frühjahrestagung, Hannover, Germany}, keywords = {}, pubstate = {published}, tppubtype = {presentation} } |