Wondering is it possible to open Google adsense ads in a new window?
Google states that it is generally not allowed:
https://support.google.com/adsense/answer/1354740?hl=en

Then what is the solution if you really hope to open ads in a new window

You will have to make use of ad server to manage all our ads inventories.
https://support.google.com/dfp_premium/answer/191228?hl=en