If using node.js, it says that you can write this:
db.collection.find( { field: /acme.*corp/i } );
//or
db.collection.find( { field: { $regex: 'acme.*corp', $options: 'i' } } );
Also, you can write this:
db.collection.find( { field: new RegExp('acme.*corp', 'i') } );