TypeError Cannot read property 'open' undifined

var app = angular.module('app',['ui.bootstrap']);

//ApplicationController
app.controller("controller", ['$scope', '$http', function($scope, $http, $modal)
{
    $scope.AnkenCheck = function(){
        $scope.newGuest = {};
        $modal.open({
                    templateUrl: "AnkenSerch",
                    scope: $scope
                    }); }
}]);