Spectroscopy of the 689 nm Sr intercombination line in a microfabricated vapor cell

We describe shelving spectroscopy measurement of the 689 nm Sr intercombination line in a microfabricated vapor cell. We demonstrate a linewidth below 200 kHz in a 9 x 14 x 4.4 mm Sr vapor cell, limited primarily by transit time broadening and residual Doppler broadening. This device will be useful for developing compact optical frequency references, as well as for laser pre-stabilization for some quantum computing platforms based on alkaline earth atoms.