Simple PHP or Javascript accept @ in the URL [duplicate]

Im looking to accept @ in the URL to pass information and parse it in the other site, but havent got it.

Example:

I have this URL

https://completeurl.com/@username

I want only the username at the end

I only manage doing something like this

https://completeurl.com/testusername.php/@something

the result in fact it is: something

but I want to be a clean URL

is it possible?