php artisan serve only starts development server by default.
You have to start browser by your own or start a script that will start php artisan serve and later start browser
or you can add
Illuminate\Foundation\Console\ServeCommand.php
$this->info("Laravel development started on http://{$host}:{$port}/");
exec('google-chrome http://localhost:8000');
Do this :
Run php artisan serve in the cli.
Then open the browser with http://localhost:8000.
As stated by @vajid you have to open browser by yourself. It wont popup.