PHP AD Authentication

<?php
    $login='domain\\username';
    $password='somepaswordwithç';
    $ldap=ldap_connect("someserver.com");
    ldap_set_option($ldap, LDAP_OPT_PROTOCOL_VERSION, 3);
    if ($bind = @ldap_bind($ldap, $login, $password)) {
        echo "ok";
    }
    else{
        echo "error while connecting";
    }
?>