If your talking about the HTTP redirect there is no such mechanism in it. It's just a simple 303 response which informs your browser to fetch the content of a page from a different URL. If you want to open a new panel/window with URL_2 after visiting URL_1 that has to be done with javascript.
Why do you want to do that anyway? Opening new panel/window is plain evil (especially if done with javascript). This should be controlled by the user, not the webapp developer who thinks he knows better what the users want. Give a normal link and let the users decide how they want to open it.
