类后端/ UsersController不存在

I am trying to separate Backend and Frontend in my project. I have Created two direcotry inside Controllers, named: frondend and backend. I have UsersController inside backend directory. I have added route for UsersController

Route::group(array('prefix' => 'backend'), function() { Route::get('users', array('as' => 'users', 'uses' => 'backend/UsersController@index')); }); I have used namespace as

namespace Controllers/backend;

in my UsersController. I run the command php artisan dump-autoload. When I try to access the routes as codefacet.loc/backend/users, it says

`ReflectionException

Class backend/UsersController does not exist`

Any help please?

Route::group(array('prefix' => 'backend'), function() {
    Route::get('users', array('as' => 'user_index', 'uses' => 'UsersController@index'));
});

the other way you can achieve that is 

Route::group(['namespace'=>'your-namespace-in-full'], function()
{
    Route::controller('users/index', 'UsersController',array(
        'index'=>'users.index',
    ));
});