M. T. Hartman

The LISA benchtop simulator at the University of Florida

At the University of Florida, we are developing an experimental Laser Interferometer Space Antenna (LISA) simulator. The foundation for the simulator is a pair of cavity-stabilized lasers that provide realistic, LISA-like phase noise. The light travel time over the five million kilometres between spacecraft is recreated in the lab by use of an electronic phase delay technique. Initial tests will focus on phasemeter implementation, time delay interferometry (TDI) and arm-locking. In this paper we present the frequency stabilization results, results from an electronic arm-locking experiment, software phasemeter performance and results from a first optical experiment to test the TDI concept. In the future, the benchtop simulator will be extended to test several other aspects of LISA interferometry such as clock noise and Doppler shifts of the signals. The eventual long-term use of the LISA simulator will be to provide realistic data streams, including all the noise components, into which model gravitational wave signals can be injected. This will make the simulator a useful testbed for data analysis research groups.

Arm‐Locking in a LISA‐like Hardware Model: A Status Report

The Laser Interferometer Space Antenna (LISA), is a proposed mission to detect gravitational waves in the mHz regime. The mission calls for a triangular constellation of three spacecraft, with inter‐spacecraft distances of approximately 5 Gm. Laser interferometry is used to measure fluctuations in the inter‐spacecraft distances to a level of ∼ 10 pm, sufficient for detecting gravitational waves. A major challenge in reaching this precision is addressing laser phase noise, which couples into the distance measurement at a level several orders of magnitude above the gravitational‐wave signal. Arm‐locking is a proposed stabilization method which uses the inter‐spacecraft distance(s) as a frequency reference. In this paper we describe the implementation of arm‐locking in an electro‐optic model of the LISA interferometer. The system includes input phase noise derived from cavity‐stabilized lasers and a single‐arm delay of 1.065 ms. The residual frequency noise of the locked system was measured to be less than 2...

Time Delay Interferometry using the UF LISA Benchtop Simulator

At the University of Florida, we are developing an experimental LISA simulator to test the implementation of various aspects of LISA interferometry including arm‐locking and time delay interferometry (TDI). Realistic light travel times are created in the lab using an electronic phase delay technique and signals are read with a LISA‐like phasemeter. TDI relies on a strong correlation between the LISA signals taken at different times and locations. In this paper, we present results from the first‐generation of the simulator showing that we are able to create LISA‐like optical signals in the lab and measure and recombine them to cancel several orders of magnitude laser phase noise.