Ultra-stable laser with spectral hole burning and multi-channel probing

Ultra-stable lasers based on spectral hole burning are a promising alternative scheme to overcome the thermal noise limitation of the traditional ultra-stable Fabry-Perot cavity scheme. In this dissertation, a Eu³⁺Y₂SiO⁵ crystal at cryogenic temperatures is used to realize narrow spectral holes as a frequency reference. A flexible and versatile multi-mode heterodyne laser probing scheme based on software defined radio is realized to achieve low detection noises.

The crystal is further cooled down to sub-kelvin temperatures to gain better thermal noise and temperature sensitivity performances. Meanwhile, some relevant spectral hole properties are characterized at this temperature regime, and some useful properties are found, which differ from theoretical predictions based on simple models.

Furthermore, a previously unobserved phenomenon, that I call “glowing”' is reported, together with preliminary analysis based on several characterization measurements, providing new insights to understand the system of Eu3+Y2SiO5 crystal.

Remarkably, the fractional frequency stability of the laser, based on the spectral hole burning scheme, has been encouragingly enhanced to 4(1)×10⁻¹⁶ at 1 s, approximately 2 times better than the previously reported results. This provides compelling evidence of the potential of the spectral hole burning approach for metrological applications.

ultra-stable laser, Eu:YSO, spectral hole, frequency metrology

Full document (EN) : TEL-04822912