Razer is bringing the opto-mechanical switches first introduced on the new Huntsman gaming keyboard to its gaming laptop models. For now, the low profile optical laptop keyboard is only available on the Blade 15 Advanced laptop, but Razer will add this feature to other 2020 models. The optical switches make use of an infrared light beam that allows for faster actuation and inputs.
https://www.notebookcheck.net/Razer-showcases-the-world-s-first-optical-laptop-keyboard.439756.0.html
It's definitely not the world's first. Those who use Tongfang models had always had the option to use optical keyboard.
Well, the Schenker XMG Neo 15 had this feature already in the beginning of 2019.