To breadboard a new conceptual stray light verification tool based on pulsed laser time of flight techniques.

Background and context: The aim of this activity is to breadboard the Straylight LIDAR instrument concept and to verify its performance experimentally. This activity aims to raise the TRL to 4 and follows the TDE activity (T216-104MM Verification of straylight rejection of optical science payloads using a pulsed laser source). The aim of this smooth follow-on is to verify the concept experimentally using an available flight spare space telescope baffle as a representative test object.Description of the concept: The technique is called ?straylight LIDAR? and the concept is based on recent research results of a number of groups working in differing fields. The range gating technique at macro (m to cm) scales using a ps laser has been shown to achieve 1 mm range resolutions. It enables very short photon pulses to be identified and resolved in x, y and t. By doing a "temporal analysis" of the straylight performance model of an optical instrument it seems feasible to identify the time gating needed to actually measure the critical straylight paths. By sweeping the time gate over the full range of response of the system, previously unidentified paths can also be detected. This is the real power of the technique. Furthermore, by varying the angle of incidence of the (pulsed laser) source with respect to the entrance aperture/baffle, and by setting the time gate and imager integration time, it seems feasible to achieve spatially and temporally resolved images of the straylight characteristics of the system under test. The principle measurable parameter used to quantify straylight performance is the Point Source Transmittance - PST. This is typically measured vs angle of incidence at the instrument entrance aperture and is the most commonly used straylight performance requirement specification for astronomical telescopes and can be derived readily from straylight models.Task list: - Assess LISA straylight verification OGSE needs vs LIDAR instrument concept performance - Use the output of the concept study to produce a Straylight LIDAR breadboard design ready for manufacture with a view of the LISA requirements - Construct and test the Straylight LIDAR breadboard - Use the Straylight LIDAR breadboard to verify and confirm the measurement of Point Source Transmittance using a piece of flight representative hardware - Evaluate the results, draw conclusions and make recommendations for developing an operational Straylight LIDAR instrument