wget -r --http-user=username --http-password=password https://server.address/folder1/folder2
In this example, folder2 within folder1 on the https server is being transferred.
However, this may result in data from the parent folder/folders being copied also. To prevent this behavior use flag --no-parent to stop parent folders from being accessed.
wget -r --http-user=username --http-password=password --no-parent https://server.address/folder1/folder2/