The “Molecular Metrology and Fundamental Tests” group of the Laboratoire de Physique des lasers (LPL) is involved in several projects dealing with ultra-stable frequency references based on detection of molecular transitions. In this context, the master student will become part of a team involved in the development of compact ultra-stable optical frequency combs based on semiconductor mode-locked lasers. Such transportable devices could play an important role in generating and distributing low phase noise optical and microwave signals. This is essential for a number of scientific and technical applications such as clocks, gravimeters, sensors, synchronization at large-scale facilities, and radar systems.
One essential step of the project is to transfer stability and accuracy of a molecular transition to the comb. The chosen molecular reference is a transition of Acetylene 13C2H2 in a cell at 1.542µm which will be probed by a single-frequency semiconductor laser. In order to increase the Signal to Noise ratio of the molecular signal, the gas-cell will be inserted into an optical resonator. In order to realize a compact system, we plan to test the metrological performances of a fiber based ring cavity. For this purpose we use an ultra-stable optical reference transmitted by the “Observatoire de Paris” (SYRTE) on an optical fiber.
Program of the internship:
Detection and characterization of linear absorption of Acetylene
Detection and characterization of the absorption in saturation spectroscopy (Doppler-free configuration)
Signal/Noise improvement by inserting the cell into an optical resonator based on fiber components
Laser frequency stabilization onto the molecular signal
Metrological characterization (noise analysis, frequency accuracy and stability)
Duration of the internship: 4 months minimum
Key words: Laser, optoelectronics, nonlinear spectroscopy, electronic servo loop, metrology.
Level required: Master degree, Engineer degree.
PhD possibility ? YES
Contact: Frédéric Du Burck