Internship offer: Development of an ultra-stable frequency laser source For LISA space mission ground tests
The recent detection of gravitational waves, using the LIGO and VIRGO ground interferometers, validates Einstein’s theory of general relativity, and gives rise to a very strong interest in the space mission LISA (Laser Interferometer in Space Antenna). This space mission, of type L3 and selected by ESA to be launched by 2034, is based on a set of three satellites flying in formation, distant from each other by 2.5 million kms. The mission’s success lies, among other things, in the frequency stability of embedded lasers for interferometric links. The current specification for residual frequency noise is 300 Hz / Hz, which will likely be reduced to 30 Hz / Hz, in order to reduce the stress on other aspects of the mission.
A French consortium composed of the CNES, several laboratories of the CNRS (INSU, IN2P3,INSIS) and of the CEA, is in charge of the AIVT aspect of the LISA mission payload. The contribution of SYRTE focuses on the development and the provision of a frequency-stabilized laser device to the consortium, in a very compact and predominantly fibered configuration.
For many years at SYRTE, we have been conducting an R & D activity on Telecom laser sources (~ 1.5 μm) tripled in frequency and stabilized on hyperfine transitions of molecular iodine in the green domain of the electromagnetic spectrum. This « Telecom laser/ iodine vapor » allows to put in place very compact and portable instrument devices, benefiting of commercial composants of great technological maturity. This approach also makes it possible to confer infrared lasers emitting in the Telecom band, a frequency stability never achieved using an atomic vapor in a cell. We have already demonstrated a stability level of 2.5×10-14t-1/2, where t is the integration time, which decreases to 3.5×10-15 after 100s of integration, for a laser operating at 1542nm and tripled in frequency. This result is expressed by the Allan standard deviation associated with the residual relative frequency noise of the stabilized laser on iodine, or ~ 7 Hz / Hz expressed in frequency noise spectral density. It already meets the most severe specifications for the perfomance of the laser of the mission, whose nominal wavelength is 1064 nm. This type of laser will be connected to the reference Telecom laser via a phase control loop associated with frequency doubling. The architecture of the entire experimental device is designed very compact, to facilitate its transport and its use outside the laboratory.
The internship proposed will allow the student to become familiar with the techniques used in the laboratory for frequency doubling / tripling, power stabilization, frequency stabilization on atomic line and phase stabilization of lasers between them. In a fist step, he will have the particular responsability to stabilize in phase two lasers emitting at 1064 nm, as well as the optical powers emitted. The optical bench will totaly be fiber.
Very motivated candidate, who has a big interest in experimental work. Good knowledge in non-linear optics and molecular spectroscopy. Basic knowledge in analog electronic would be apreciated.
3 to 4 months.
Forecast start date: April 2019
Paid internship: Yes
Level of qualification required: Master 2
Internship place: Laboratoire SYRTE- UMR 8630/ Observatoire de Paris. 77 avenue Denfert-Rochereau, Paris F-75014
Access and transports : Métro, RER B, Bus
Tel. 33(0)1 40 50 20 50