Optimal binary gratings for multi-wavelength magneto-optical traps

Abstract

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.

11 pages, 3 figures, 2 tables. See also 4-page supplementary document

References in corpus (13)

• Magneto-optical trapping of a diatomic molecule
• Grating chips for quantum technologies
• Laser cooling with a single laser beam and a planar diffractor
• Laser cooling in a chip-scale platform
• Invited Review: Micro-fabricated components for cold atom sensors
• Phase-space properties of magneto-optical traps utilising micro-fabricated gratings
• Two-stage magneto-optical trapping and narrow-line cooling of ${}^6$Li atoms to high phase-space density
• Grating magneto-optical traps with complicated level structures
• Narrow-line cooling of ${}^{87}$Rb using 5S${}_{1/2}\to$ 6P${}_{3/2}$ open transition at 420 nm
• Narrow-linewidth cooling of ${}^6$Li atoms using the 2S-3P transition
• Characterization of Suspended Membrane Waveguides towards a Photonic Atom Trap Integrated Platform
• A grating-chip atomic fountain
• Demonstration of a MOT in a Sub-Millimeter Membrane Hole

Cited by in corpus (2)

• Single-beam grating-chip 3D and 1D optical lattices
• A high-flux cold-atom source utilising a grating atom chip