AngularJS 2 rc.4 cannot find name 'google'. hatasi

Selamun Aleyküm, Ionic 2 ögrenmekteyim, map.component.ts'de google:any, ve initializeMap metodun altinda var google; olarak denedim basarili olamadim. Acaba google classini nasil tanitabilirim typescript motoruna? map.component.ts su sekilde;

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export class MapComponent {

          constructor(private navCtrl: NavController) {
                this.initializeMap();
          }

        initializeMap(){
          var minZoomLevel = 15;

           this.map = new google.maps.Map(document.getElementById('map_canvas'), {
             zoom: minZoomLevel,
             center: new google.maps.LatLng(52.5200, 13.4050),
             mapTypeId: google.maps.MapTypeId.ROADMAP,
             disableDefaultUI: true,
             zoomControl: true
           });
         }

        }