Laravel DomPdf不支持UTF-8

i'm trying to use dompdf in laravel 4.2, in that document for support utf-8 i must be set

in meta tag, but does not work correctly. for example after pass string such as latin character such as Hello World, this package can create currect PDF, but when i set Arabic or Persian character such as سلام. created pdf file is empty without any string. i think my code is correct and this package dont support correct utf8

My code is:

$pdf = App::make( 'dompdf' );
$pdf->loadHTML( '<html lang="en"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"/><title>PDF</title></head><body><h1>سلام</h1></body></html>' );

return $pdf->stream();

You can use the TCPPDF It is available at the link below: laravel-tcpdf