ArcGisServer.html

<!DOCTYPE html>
<head>
    <title>ArcGIS</title>
    <link href="../Build/Cesium/Widgets/widgets.css" rel="stylesheet">
    <script type="text/javascript" src="./js/require.min.js" data-main="./js/main"></script>
</head>
<body>
<div id="cesiumContainer"></div>
<script>
    function onload(Cesium) {
        var viewer = new Cesium.Viewer('cesiumContainer', {
            imageryProvider : new Cesium.ArcGisMapServerImageryProvider({
                url : 'http://atlasmaps.esri.com/arcgis/rest/services/Esri/USA_Population_Density/MapServer',
                enablePickFeatures : false
            }),
           baseLayerPicker : false
        });

        var test =  new Cesium.ArcGisMapServerImageryProvider({
            url : 'http://atlasmaps.esri.com/arcgis/rest/services/Esri/USA_Population_Density/MapServer',
            enablePickFeatures : false
        });

        var imageryLayers = viewer.imageryLayers;

        imageryLayers.addImageryProvider(test);
    };
</script>
</body>