Author Correction: Hard X-ray transient grating spectroscopy on bismuth germanate

Correction to: Nature Photonics https://doi.org/10.1038/s41566-021-00797-9, published online 22 April 2021.

In the version of this Letter originally published, the text ‘The spot size at the sample was tuned to 190 × 150 mm²’ in the Methods was incorrect; it should have read ‘The spot size at the sample was tuned to 190 × 150 µm²’. This has now been corrected in all versions of the Letter.