Best way to initialize empty array in PHP

Question

Because of object creation and instantiation, it has been observed that initialising a new array using the syntax var foo = [] rather than var foo = new Array() is faster in some other languages (like AS3, for instance). I'm curious if PHP has any equivalent concepts.

class Foo {
    private $arr = array(); // is there another / better way?
}

Can someone please help me with this?