Grating magneto-optical traps are an enabling quantum technology for portable metrological devices with ultracold atoms. However, beam diffraction efficiency and angle are affected by wavelength, creating a single-optic design challenge for laser cooling in two stages at two distinct wavelengths - as commonly used for loading, e.g., Sr or Yb atoms into optical lattice or tweezer clocks. Here, we optically characterize a wide variety of binary gratings at different wavelengths to find a simple empirical fit to experimental grating diffraction efficiency data in terms of dimensionless etch depth and period for various duty cycles. The model avoids complex 3D light-grating surface calculations, yet still yields results accurate to a few percent across a broad range of parameters. Gratings optimized for two (or more) wavelengths can now be designed in an informed manner suitable for a wide class of atomic species enabling advanced quantum technologies.Grating magneto-optical traps are an enabling quantum technology for portable metrological devices with ultracold atoms. However, beam diffraction efficiency and angle are affected by wavelength, creating a single-optic design challenge for laser cooling in two stages at two distinct wavelengths - as commonly used for loading, e.g., Sr or Yb atoms into optical lattice or tweezer clocks. Here, we optically characterize a wide variety of binary gratings at different wavelengths to find a simple empirical fit to experimental grating diffraction efficiency data in terms of dimensionless etch depth and period for various duty cycles. The model avoids complex 3D light-grating surface calculations, yet still yields results accurate to a few percent across a broad range of parameters. Gratings optimized for two (or more) wavelengths can now be designed in an informed manner suitable for a wide class of atomic species enabling advanced quantum technologies.

arXiv:2306.17080Jun 29, 20230 citations

Two-color grating magneto-optical trap for narrow-line laser cooling

Saskia Bondza, Christian Lisdat, Stefanie Kroker +1 more

We demonstrate for the first time the two-color cooling and trapping of alkaline-earth atoms in a grating magneto-optical trap (gMOT). The trap is formed by a single incident laser beam together with four secondary beams that are generated via diffraction from a nanostructured wafer. A grating structure for a gMOT operating with strontium atoms is optimized and fabricated. We trap $10^6$ $^{88}$ Sr atoms on the $^1$ S $_0$ $\rightarrow$ $^1$ P $_1$ transition at $461\;\mathrm{nm}$ and transfer $25\;\%$ of these atoms to the second cooling stage on the narrower $^1$ S $_0$ $\rightarrow$ $^3$ P $_1$ intercombination transition at $689\;\mathrm{nm}$ , preparing a sample of $2.5\times 10^5$ atoms at $5\;μ$ K. These results demonstrate for the first time the applicability of the gMOT technology in conjunction with two widely differing wavelengths and enable the continued miniaturization of alkaline-earth based quantum technologies like optical atomic clocks.We demonstrate for the first time the two-color cooling and trapping of alkaline-earth atoms in a grating magneto-optical trap (gMOT). The trap is formed by a single incident laser beam together with four secondary beams that are generated via diffraction from a nanostructured wafer. A grating structure for a gMOT operating with strontium atoms is optimized and fabricated. We trap $10^6$ $^{88}$Sr atoms on the $^1$S$_0$ $\rightarrow$ $^1$P$_1$ transition at $461\;\mathrm{nm}$ and transfer $25\;\%$ of these atoms to the second cooling stage on the narrower $^1$S$_0$ $\rightarrow$ $^3$P$_1$ intercombination transition at $689\;\mathrm{nm}$, preparing a sample of $2.5\times 10^5$ atoms at $5\;μ$K. These results demonstrate for the first time the applicability of the gMOT technology in conjunction with two widely differing wavelengths and enable the continued miniaturization of alkaline-earth based quantum technologies like optical atomic clocks.

arXiv:2112.08833Dec 16, 20210 citations

Dual atom ( 87 Rb- 133 Cs) grating magneto-optical trap

Lei Xu, Muming Li, Zhilong Yu +5 more

This paper proposes a dual-color grating chip design method for simultaneously capturing dual atomic clouds ( 87 Rb and 133 Cs). By simulating key parameters such as the grating period, etching depth, duty cycle, coating material, and thickness, the optimal design parameters were determined ( T = 210 nm, r = 0.5, h 0 = 100 nm, d = 1150 nm) to ensure efficient dual-wavelength diffraction and maximize the number of captured atoms. Experimental results demonstrate the simultaneous trapping of 1.6 × 10 8 87 Rb atoms and 7.8 × 10 6 133 Cs atoms, thereby offering an approach for multi-species cold atom systems. This dual-species grating magneto-optical trap (GMOT) system has potential applications in precision measurements such as cold atom clocks, quantum interferometers, and quantum electrometry.This paper proposes a dual-color grating chip design method for simultaneously capturing dual atomic clouds ( 87 Rb and 133 Cs). By simulating key parameters such as the grating period, etching depth, duty cycle, coating material, and thickness, the optimal design parameters were determined ( T = 210 nm, r = 0.5, h 0 = 100 nm, d = 1150 nm) to ensure efficient dual-wavelength diffraction and maximize the number of captured atoms. Experimental results demonstrate the simultaneous trapping of 1.6 × 10 8 87 Rb atoms and 7.8 × 10 6 133 Cs atoms, thereby offering an approach for multi-species cold atom systems. This dual-species grating magneto-optical trap (GMOT) system has potential applications in precision measurements such as cold atom clocks, quantum interferometers, and quantum electrometry.

Optics ExpressJan 24, 202511 citations

Dual atom (87Rb-133Cs) grating magneto-optical trap

Lei Xu, Muming Li, Zhilong Yu +5 more

This paper proposes a dual-color grating chip design method for simultaneously capturing dual atomic clouds (87Rb and 133Cs). By simulating key parameters such as the grating period, etching depth, duty cycle, coating material, and thickness, the optimal design parameters were determined to ensure efficient dual-wavelength diffraction and maximize the number of captured atoms. Experimental results demonstrate the simultaneous trapping of 1.6E8 87Rb atoms and 7.8E6 133Cs atoms, thereby offering an approach for multi-species cold atom systems. This dual-species grating magneto-optical trap (GMOT) system has potential applications in precision measurements such as cold atom clocks, quantum interferometers, and quantum electrometry.This paper proposes a dual-color grating chip design method for simultaneously capturing dual atomic clouds (87Rb and 133Cs). By simulating key parameters such as the grating period, etching depth, duty cycle, coating material, and thickness, the optimal design parameters were determined to ensure efficient dual-wavelength diffraction and maximize the number of captured atoms. Experimental results demonstrate the simultaneous trapping of 1.6E8 87Rb atoms and 7.8E6 133Cs atoms, thereby offering an approach for multi-species cold atom systems. This dual-species grating magneto-optical trap (GMOT) system has potential applications in precision measurements such as cold atom clocks, quantum interferometers, and quantum electrometry.

arXiv:2412.14440Dec 19, 20240 citations

Two-Color Grating Magneto-Optical Trap for Narrow-Line Laser Cooling

Saskia Bondza, Christian Lisdat, Stefanie Kroker +1 more

We demonstrate the two-color cooling and trapping of alkaline-earth atoms in a grating magneto-optical trap (GMOT). The trap is formed by a single incident laser beam together with four secondary beams that are generated via diffraction from a nanostructured wafer. A grating structure for a GMOT operating with strontium atoms is optimized and fabricated. We trap ${10}^{6}{\phantom{\rule{0.2em}{0ex}}}^{88}\mathrm{Sr}$ atoms on the ${}^{1}{S}_{0}{\ensuremath{\rightarrow}}^{1}{P}_{1}$ transition at $461\phantom{\rule{0.2em}{0ex}}\mathrm{nm}$ and transfer 25% of these atoms to the second cooling stage on the narrower ${}^{1}{S}_{0}{\ensuremath{\rightarrow}}^{3}{P}_{1}$ intercombination transition at $689\phantom{\rule{0.2em}{0ex}}\mathrm{nm}$ , preparing a sample of $2.5\ifmmode\times\else\texttimes\fi{}{10}^{5}$ atoms at $5\phantom{\rule{0.2em}{0ex}}\ensuremath{\mu}\mathrm{K}$. These results demonstrate the applicability of the GMOT technology in conjunction with two widely differing wavelengths and enable the continued miniaturization of alkaline-earth-based quantum technologies like optical atomic clocks.We demonstrate the two-color cooling and trapping of alkaline-earth atoms in a grating magneto-optical trap (GMOT). The trap is formed by a single incident laser beam together with four secondary beams that are generated via diffraction from a nanostructured wafer. A grating structure for a GMOT operating with strontium atoms is optimized and fabricated. We trap ${10}^{6}{\phantom{\rule{0.2em}{0ex}}}^{88}\mathrm{Sr}$ atoms on the ${}^{1}{S}_{0}{\ensuremath{\rightarrow}}^{1}{P}_{1}$ transition at $461\phantom{\rule{0.2em}{0ex}}\mathrm{nm}$ and transfer 25% of these atoms to the second cooling stage on the narrower ${}^{1}{S}_{0}{\ensuremath{\rightarrow}}^{3}{P}_{1}$ intercombination transition at $689\phantom{\rule{0.2em}{0ex}}\mathrm{nm}$, preparing a sample of $2.5\ifmmode\times\else\texttimes\fi{}{10}^{5}$ atoms at $5\phantom{\rule{0.2em}{0ex}}\ensuremath{\mu}\mathrm{K}$. These results demonstrate the applicability of the GMOT technology in conjunction with two widely differing wavelengths and enable the continued miniaturization of alkaline-earth-based quantum technologies like optical atomic clocks.

Physical Review AppliedApr 1, 202225 citations

Diffractive chips for magneto-optical trapping of two atomic species

Zhaoning Yu, Garrett Hickman, Mark E. Saffman +1 more

Grating-based structures have recently been used as components of magneto-optical traps (MOT) to simplify the setup for trapping Rb atoms. Here, we design diffractive chips to trap more than one atom species. Our full-wave simulations show that a two-dimensional (2D) grating chip can simultaneously have high force-balancing efficiency for a wavelength of 780 nm for trapping Rb atoms and a wavelength of 852 nm for Cs atoms. We fabricated and characterized a mm-scale grating chip using electron-beam lithography, and are in the process of trapping experiments. Our work opens the door to compact multi-species MOTs.Grating-based structures have recently been used as components of magneto-optical traps (MOT) to simplify the setup for trapping Rb atoms. Here, we design diffractive chips to trap more than one atom species. Our full-wave simulations show that a two-dimensional (2D) grating chip can simultaneously have high force-balancing efficiency for a wavelength of 780 nm for trapping Rb atoms and a wavelength of 852 nm for Cs atoms. We fabricated and characterized a mm-scale grating chip using electron-beam lithography, and are in the process of trapping experiments. Our work opens the door to compact multi-species MOTs.

Quantum Nanophotonic Materials, Devices, and SystemsAug 20, 20200 citations

10^6

^{88}

Sr atoms on the

^1

_0

\rightarrow

^1

_1

transition at

461\;\mathrm{nm}

and transfer

25\;\%

of these atoms to the second cooling stage on the narrower

^1

_0

\rightarrow

^3

_1

intercombination transition at

689\;\mathrm{nm}

, preparing a sample of

2.5\times 10^5

atoms at

5\;μ

K. These results demonstrate for the first time the applicability of the gMOT technology in conjunction with two widely differing wavelengths and enable the continued miniaturization of alkaline-earth based quantum technologies like optical atomic clocks.

{10}^{6}{\phantom{\rule{0.2em}{0ex}}}^{88}\mathrm{Sr}

atoms on the ${}^{1}{S}_{0}{\ensuremath{\rightarrow}}^{1}{P}_{1}$ transition at

461\phantom{\rule{0.2em}{0ex}}\mathrm{nm}

and transfer 25% of these atoms to the second cooling stage on the narrower ${}^{1}{S}_{0}{\ensuremath{\rightarrow}}^{3}{P}_{1}$ intercombination transition at

689\phantom{\rule{0.2em}{0ex}}\mathrm{nm}

, preparing a sample of $2.5\ifmmode\times\else\texttimes\fi{}{10}^{5}$ atoms at $5\phantom{\rule{0.2em}{0ex}}\ensuremath{\mu}\mathrm{K}$. These results demonstrate the applicability of the GMOT technology in conjunction with two widely differing wavelengths and enable the continued miniaturization of alkaline-earth-based quantum technologies like optical atomic clocks.