A Two-Dimensional Magneto-Optical Trap for a Strontium Clock

Atomic Caesium clocks have made an astonishing development in the past few decades, with them gaining an order of magnitude in precision every decade. A new generation of atomic optical clocks is now emerging, which is moving to the forefront of timekeeping. By going from microwave to optical frequencies these clocks are now reaching fractional uncertainty levels in the 10\$^-\$\$^1\$\$^8\$, opening a whole new range of exciting applications. This thesis presents the design and implementation of an experiment for laser cooling of strontium atoms, focusing on the mobility of the setup, opening a range of new applications as a mobile clock. The experimental apparatus applies a range of new techniques for strontium, such as the use of a two dimensional magneto-optical trap for pre cooling atoms, allowing for a compact and transportable system. A mobile laser system for laser cooling strontium atoms was realized. This includes a frequency doubling system for the main cooling transition. The constructed monolithic frequency doubling cavity has generated 300 mW of blue light and proven to be a stable setup suitable for a mobile system. The 3D-MOT was able to capture 4 * 10\$^5\$ atoms with a long lifetime of 5.5 s, with further improvements for a significant increase in atom number currently being implemented.Atomic Caesium clocks have made an astonishing development in the past few decades, with them gaining an order of magnitude in precision every decade. A new generation of atomic optical clocks is now emerging, which is moving to the forefront of timekeeping. By going from microwave to optical frequencies these clocks are now reaching fractional uncertainty levels in the 10\$^-\$\$^1\$\$^8\$, opening a whole new range of exciting applications. This thesis presents the design and implementation of an experiment for laser cooling of strontium atoms, focusing on the mobility of the setup, opening a range of new applications as a mobile clock. The experimental apparatus applies a range of new techniques for strontium, such as the use of a two dimensional magneto-optical trap for pre cooling atoms, allowing for a compact and transportable system. A mobile laser system for laser cooling strontium atoms was realized. This includes a frequency doubling system for the main cooling transition. The constructed monolithic frequency doubling cavity has generated 300 mW of blue light and proven to be a stable setup suitable for a mobile system. The 3D-MOT was able to capture 4 * 10\$^5\$ atoms with a long lifetime of 5.5 s, with further improvements for a significant increase in atom number currently being implemented.

Dec 1, 20136 citations

Cooling Strontium in a Narrow Line Magneto-Optical Trap

Benjamin J. Reschovsky, Daniel S. Barker, Neal C. Pisenti +1 more

Bulletin of the American Physical SocietyJun 4, 20140 citations

A Novel Laser Activated Atom Source for Portable Strontium Optical Lattice Atomic Clocks

Jonathan Bass, Matthew Aldous, David C. Morris +3 more

Atomic clocks have been in common use since the 1950s and over this period the clock community has had two main goals: increasing the performance of the clocks and increasing their portability. At Birmingham we aim to compress a strontium optical lattice clock, a clock with an extremely high accuracy, into a portable package. Many novel approaches need to be employed to allow such a clock to operate with a favorable SWaP while maintaining the low instability and uncertainty that makes optical clocks a desirable frequency standard. The focus of this work is to use laser activation of a strontium compound as the atomic source for the clock. Previously work published by this group [1] demonstrated that it is possible to release the strontium atoms from strontium oxide successfully load a magneto-optical trap (MOT).Atomic clocks have been in common use since the 1950s and over this period the clock community has had two main goals: increasing the performance of the clocks and increasing their portability. At Birmingham we aim to compress a strontium optical lattice clock, a clock with an extremely high accuracy, into a portable package. Many novel approaches need to be employed to allow such a clock to operate with a favorable SWaP while maintaining the low instability and uncertainty that makes optical clocks a desirable frequency standard. The focus of this work is to use laser activation of a strontium compound as the atomic source for the clock. Previously work published by this group [1] demonstrated that it is possible to release the strontium atoms from strontium oxide successfully load a magneto-optical trap (MOT).

Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFCS)Apr 1, 20190 citations

Mercury optical lattice clock with a 2D magneto-optical trap

M. Andia, Changlei Guo, Valentin Cambier +26 more

Dec 9, 20190 citations

A ring magneto-optical trap

M. Morinaga

Conference on Lasers and Electro-OpticsJan 1, 20050 citations

Midinfrared magneto-optical trap of metastable strontium for an optical lattice clock

Richard Hobson, William Bowden, Alvise Vianello +2 more

We report on the realization of a magneto-optical trap (MOT) for metastable strontium operating on the 2.92-$\ensuremath{\mu}\mathrm{m}$ transition between the energy levels $5s5p{\phantom{\rule{0.16em}{0ex}}}^{3}{P}_{2}$ and $5s4d{\phantom{\rule{0.16em}{0ex}}}^{3}{D}_{3}$ . The strontium atoms are initially captured in a MOT operating on the 461-nm transition between the energy levels $5{s}^{2}{\phantom{\rule{0.16em}{0ex}}}^{1}{S}_{0}$ and $5s5p{\phantom{\rule{0.16em}{0ex}}}^{1}{P}_{1}$ , prior to being transferred into the metastable MOT and cooled to a final temperature of 6 $\ensuremath{\mu}\mathrm{K}$. Challenges arising from aligning the midinfrared and 461-nm light are mitigated by employing the same pyramid reflector to realize both MOTs. Finally, the 2.92-$\ensuremath{\mu}\mathrm{m}$ transition is used to realize a full cooling sequence for an optical lattice clock, in which cold samples of $^{87}\mathrm{Sr}$ are loaded into a magic-wavelength optical lattice and initialized in a spin-polarized state to allow high-precision spectroscopy of the $5{s}^{2}{\phantom{\rule{0.16em}{0ex}}}^{1}{S}_{0}$ to $5s5p{\phantom{\rule{0.16em}{0ex}}}^{3}{P}_{0}$ clock transition.We report on the realization of a magneto-optical trap (MOT) for metastable strontium operating on the 2.92-$\ensuremath{\mu}\mathrm{m}$ transition between the energy levels $5s5p{\phantom{\rule{0.16em}{0ex}}}^{3}{P}_{2}$ and $5s4d{\phantom{\rule{0.16em}{0ex}}}^{3}{D}_{3}$. The strontium atoms are initially captured in a MOT operating on the 461-nm transition between the energy levels $5{s}^{2}{\phantom{\rule{0.16em}{0ex}}}^{1}{S}_{0}$ and $5s5p{\phantom{\rule{0.16em}{0ex}}}^{1}{P}_{1}$, prior to being transferred into the metastable MOT and cooled to a final temperature of 6 $\ensuremath{\mu}\mathrm{K}$. Challenges arising from aligning the midinfrared and 461-nm light are mitigated by employing the same pyramid reflector to realize both MOTs. Finally, the 2.92-$\ensuremath{\mu}\mathrm{m}$ transition is used to realize a full cooling sequence for an optical lattice clock, in which cold samples of $^{87}\mathrm{Sr}$ are loaded into a magic-wavelength optical lattice and initialized in a spin-polarized state to allow high-precision spectroscopy of the $5{s}^{2}{\phantom{\rule{0.16em}{0ex}}}^{1}{S}_{0}$ to $5s5p{\phantom{\rule{0.16em}{0ex}}}^{3}{P}_{0}$ clock transition.

arXiv:2001.05210Physical Review AJan 14, 202023 citations

We report on the realization of a magneto-optical trap (MOT) for metastable strontium operating on the 2.92-$\ensuremath{\mu}\mathrm{m}$ transition between the energy levels

5s5p{\phantom{\rule{0.16em}{0ex}}}^{3}{P}_{2}

and

5s4d{\phantom{\rule{0.16em}{0ex}}}^{3}{D}_{3}

. The strontium atoms are initially captured in a MOT operating on the 461-nm transition between the energy levels

5{s}^{2}{\phantom{\rule{0.16em}{0ex}}}^{1}{S}_{0}

and

5s5p{\phantom{\rule{0.16em}{0ex}}}^{1}{P}_{1}

, prior to being transferred into the metastable MOT and cooled to a final temperature of 6 $\ensuremath{\mu}\mathrm{K}$. Challenges arising from aligning the midinfrared and 461-nm light are mitigated by employing the same pyramid reflector to realize both MOTs. Finally, the 2.92-$\ensuremath{\mu}\mathrm{m}$ transition is used to realize a full cooling sequence for an optical lattice clock, in which cold samples of

^{87}\mathrm{Sr}

are loaded into a magic-wavelength optical lattice and initialized in a spin-polarized state to allow high-precision spectroscopy of the

5{s}^{2}{\phantom{\rule{0.16em}{0ex}}}^{1}{S}_{0}

5s5p{\phantom{\rule{0.16em}{0ex}}}^{3}{P}_{0}

clock transition.