How can I avoid wasted space on Google searches on large monitors?

There is a lot of wasted space in Google searches (in Chrome) on my 23″ monitor (1920×1080 resolution):

(click image to enlarge)

As you can see, less than 1/3 of the full screen width is actually used, and the rest of the precious screen space remains blank.

Is there any way to optimize Google for larger screens?

Your issue is with Google’s webpage and not your system. Maybe a browser extension can make the page appear more aesthetically pleasing. You could lower your monitor resolution. Or as someone else suggested, rotate your display 90 degrees. Holding CTRL button and using the mouse wheel will often adjust the magnification of text. Otherwise, write Google a nice letter because they would need to modify the code.

Rotate your screen 90 degrees. It makes use of your screen and google’s new super-narrow results format.

More seriously, you might be able to do something with creating a “Google Custom Search“, unless you think that does not address your question (it won’t help google.com’s direct results, but it will let you search google and purports to provide options you can set about how the results look.)