Hello Chetan this is something you would need to build a custom indexer for. By default search fields are indexed as text fields by converting the datetime to a search string using:
SearchValueConverter.DateToString(value);
if you create a custom index like this:
https://docs.kentico.com/display/K82/Creating+custom+smart+search+indexes
you could control what is put in your field and even do some logic before it is inserted as a generalfield