Research objectives and content
Light is confined in 100 pim silica microspheres, by total internal reflection, in a wavelength-sized equatorial ring. Whispering-gallery modes (WGM) yield high-Q resonances (photon lifetime 1 ms). The electric field per photon is high and strong cavity effects are expected. This made it possible to realize low threshold microlaser with Nd-doped microspheres. Nd microlasers are now studied at low temperatures to achieve thresholdless regime with a few active ions. The quantum effects associated to the dynamics of these lasers will be studied in details. These experiments are expected to bring information on neodymium ions in silica. They are a step toward Cavity QED experiments with a few atoms coupled to a WGM.
At room temperature, up-conversion in erbium can provide green laser light with a pump diode laser at 800 nm. Laser action has not been demonstrated in silica fibers. Since microspheres are efficient laser cavities, Er-doped microspheres are tested for laser action.
Training content (objective, benefit and expected impact)
I will improve my knowledge on: - diode lasers, integrated optics, high efficiency detection, high resolution spectroscopy. - cryogenics. I also expect theoretical training in: - Quantum Optics - Cavity-QED in the optical domain
Links with industry/industrial relevance
- Patents on special microlasers (green microlasers) - Contacts with CNET-France Telecom.