@Georgia19
Thanks for the post.
The Roku Streaming stick will not be able to connect optically to external devices. The Streaming Stick will need to be connected to the TV and the TV will then need to be connected to your external audio devices. The issue you are experiencing would appear to be related to your TV and audio products connection.
How are you connecting your Samsung TV to your Polk audio products?
Please keep us posted and we will be able to assist you further.
Thanks,
Danny
Danny R.
Roku Community Moderator