Duration: 16 months
Optical clocks exhibit superior accuracy compared to microwave counterparts, making them essential for space-based PNT applications and satellite communications. The integration of miniaturized atomic standards with photonic integrated circuits (PICs) represents a major challenge for enhanced performance of stable and deployable clocks. QSENSATO’s approach is leveraged by the patented Laser-Written Vapor Cell (LWVC) technology, an out-of-the-box solution that allows for all-glass atomic-photonic chips, providing unprecedented combination of accuracy, integration and robustness. Utilizing two-photon absorption, the pump laser frequency is locked to the fluorescence signal via a feedback loop, eliminating the need for high-vacuum systems and complex laser cooling.
In contrast with MEMS vapor cells, LWVCs are all-glass transparent components inscribed with a maskless fabrication method. This bestows advantages over MEMS, such as reduced manufacturing complexity, 3D geometric versatility and multiple optical access. The femtosecond laser writing (FLW) technology enables fabrication of PICs and waveguides in the same chip. This will be merged with PIC-based ring resonators and laser sources into modern architectures of chip-scale optical clocks.
We propose a LWVC-based frequency reference comprising an alkali-metal-vapor cell with filters and reflectors, integrated micro-lenses, and waveguides in glass. The frequency reference is based on two-photon absorption and will contain a single laser input and stabilization signal output from the detected fluorescence signal. Given its isotropic nature and LWVC transparency, detection can be perpendicular with respect to the pump laser.
The idea advances:
-atomic-photonic chip integration without off-chip laser propagation
-reduction in fabrication complexity and simplified passive alignment
-enhanced fluorescence signal detection due to geometric versatility
-reduced helium leakage into the vapor cell by appropriate glass choice
