Microwave dressed polar molecules in two-dimensional optical lattices

A gas of ultracold polar molecules trapped in an optical lattice provides a powerful platform for realizing lattice spin models and Hubbard models with longer-range interactions. In this context, realizing the most interesting phases requires a sample with low entropy and collisional stability. However, the inelastic collisions between molecules prevents efficient preparation of such samples. Here we report on loading microwave dressed ²³Na⁴⁰K molecules into a few layers of two-dimensional optical lattices. The microwave-dressed molecules are not only shielded from two-body inelastic collisions, but also feature strong elastic dipolar collisions.These properties allows for coherent tunneling and thermalization in the lattices, thus improve the loading efficiency.  We achieved more than 15% filling fraction and observe 10 seconds lifetime of molecules in a deep lattice. Our results lay the groundwork for future studies of many-body physics with polar molecules in optical lattices.