Do gravitational waves stretch the wavelength of light?

[jonah]

We often get some version of this question:

“If a gravitational wave stretches the distance between the LIGO mirrors, doesn’t it also stretch the wavelength of the laser light? If so, then how can LIGO detect gravitational waves?”

This is a great question! Here are a few different resources for understanding the answer:

https://www.ligo.org/science/faq.php#mirror-distance

Q: If Light is Stretched/Compressed by a GW, Why Use Light Inside LIGO?

https://www.americanscientist.org/article/wavy-gravy

If light waves are stretched by gravitational waves, how can we use light as...