We are partners in the UK Hub for Quantum Enabled Position, Navigation and Timing with a core aim of reducing the size, weight, power and cost of the lasers and photonic components for cold atom systems. In particular we have demonstrated DFB lasers at 778.1 nm wavelength with 58 mW output power and 3.76 kHz linewidth. We have also developed silicon nitride waveguides for photonic integrated circuits at 778 / 780 nm with losses below 0.15 dB/cm and demonstrated integrated DFB lasers on the same chip. Microrings with a Q > 1.4M have been demonstrated at 780 nm wavelength. We have also demonstrated MEMS vacuum cells with Rb vapour for locking the lasers to the 87Rb D2 atomic transition. Our ultimate aim is to produce all the required photonic components for cold atom systems on a chip to provide significant miniaturisation from the present technology.

1. Chip-scale atomic spectrometer with silicon nitride optical phased array APL Photonics 10(7), 076104 (2025) - DOI 10.1063/5.0273108
   J. Januszewicz, A.P. McWilliams, S. Dyer, J.P. McGilligan, P.F. Griffin,E. Riis, E. Di Gaetano, M. Sorel, D.J. Paul and K. Gallacher


2. 778.1 nm distributed feedback lasers for Rb two-photon atomic systems with sub-4 kHz linewidths APL Photonics 9(5), 056114 (2024) - DOI 10.1063/5.0191088
   E. Di Gaetano, B. Keliehor, K. Gallacher, P.F. Griffin, M. Sorel, E. Riis and D.J. Paul


3. "Chip-Scale Packages for a Tunable Wavelength Reference and Laser Cooling Platform" Physical Review Applied 19, 044015 (2023) - DOI: 10.1103/PhysRevApplied.19.044015
   S. Dyer, K. Gallacher, U. Hawley, A. Bregazzi, P.F. Griffin, A.S. Arnold, D.J. Paul, E. Riis and J.P. McGilligan


4. "Micro-fabricated components for cold atom sensors" Review of Scientific Instruments 93, 091101 (2022) - DOI: 10.1063/5.0101628
   J.P. McGilligan, K. Gallacher, P.F. Griffin, D.J. Paul, A.S. Arnold and E. Riis


5. "Silicon nitride waveguide polarization rotator and polarization beam splitter for chip-scale atomic systems " APL Photonics 7(4), 046101 (2022) - DOI 10.1063/5.0077738 - Supplementary material
   K. Gallacher, P.F. Griffin, E. Riis, M. Sorel and D.J. Paul


6. "Sub-MHz linewidth 780.24 nm distributed feedback laser for ⁸⁷Rb applications" Optics Letters 45(13) pp. 3529 - 3532 (2020) - DOI: 10.1364/OL.394185
   E. Di Gaetano, S. Watson, E. McBrearty, M. Sorel and D.J. Paul


7. "1.4 million Q factor Si₃N₄ micro-ring resonator at 780 nm wavelength for chip-scale atomic systems" Optics Express 28(3), pp. 4010 - 4020 (2020) - DOI: https://doi.org/10.1364/OE.381224
   M. Sinclair, K. Gallacher, M. Sorel, J. Bayley, E. McBrearty, R.W. Millar, S. Hild, and D.J. Paul


8. "Integrated DFB Lasers on Si₃N₄ Photonic Platform for Chip-Scale Atomic Systems" Conference on Lasers and Electro-Optics, paper STu4O.7 (2019) 10.1364/CLEO_SI.2019.STu4O.7
   K Gallacher, M. Sinclair, R W. Millar, O. Sharp, F Mirando, G. Ternent, G. Mills, B. Casey and D J. Paul


9. "The UK National Quantum Technologies Hub in sensors and metrology (Keynote Paper)" Proceedings SPIE 9900, 990009 (2016) - DOI: 10.1117/12.2232143
   K. Bongs et al.