How to define private-file-access Route in lumen

private-file-access Route is working in laravel but not working in lumen

When I hit api "http://localhost:/8000/api/profile/img.png"

1. this api is working in laravel but not working in lumen

   $router->get('api/profile/{data:.*}','FileManager\UserController@profilePic'); //this api is working in laravel but not working in lumen

2. this api is working in laravel but we can't define this way in lumen

   Route::get('api/profile/{data:.}','FileManager\UserController@profilePic')->where('data', '.'); //this api is working in laravel but we can't define this way in lumen