Narrow linewidth lasers are important tools for fundamental and applied physics. Indeed, atomic physics requires highly stable lasers to manipulate atoms through light-matter interaction, i.e. optical pumping, optical cooling, and high resolution and high sensitivity spectroscopy to measure the hyperfine structure of electronic transitions. The narrower the laser linewidth, the better the frequency resolution and the signal to noise ratio. On the other hand, miniature low noise blue and violet semiconductor lasers will also find technological applications for underwater coherent optical telecommunications, lithography, optical data storage and Raman spectroscopy for biomedical applications and environmental monitoring investigation (e.g. highly sensitive gases trace detection). Nowadays, the red and infrared parts of the electromagnetic spectrum are well covered by compact ultrastable semiconductor lasers. However, miniature ultralow noise blue lasers are still lacking.
The aim of this project is to realize miniature III-nitride highly coherent single mode blue lasers. Two main breakthroughs are targeted. The first of them is the demonstration of electrically pumped narrow linewidth single mode Fabry-Perot (SFP) lasers ; the second one is the implementation of a linewidth narrowing technique based on the implementation of resonant optical feedback with a linewidth reduction as large as tens of thousands. The ultimate goal is to link together the two objectives to decrease blue laser linewidth down to the sub-kHz regime. The novelty of this project is to address an original approach based on the combination of an InGaN-based SFP laser diode coupled to a high-quality factor whispering gallery mode (WGM) micro-resonator. Unprecedented characteristics overcoming those of state of the art narrow linewidth blue lasers with high frequency and intensity stability emitting milliwatts of output power will be obtained.
LASPE-EPFL
(groupes Foton : gr1 - gr2)
Campus France (