How to validate an Input Array field in Laravel 5.1?

How can I write rule for input field like below:

{!! Form::number("amount[]",null,['min' => 0, 'class' => 'form-control col-xs-2 ']) !!}

I tried following which gave error: htmlentities() expects parameter 1 to be string, array given

        $rules = array(
            'amount[]' => 'required'
        );
        $this->validate($request, $rules);

via Chebli Mohamed