Create strings depending on template arguments

I have many classes/methods like this:

template<typename CharT, typename TraitsT = std::char_traits<CharT> >
struct Foo
{
   std::basic_string<CharT, TraitsT> getFoo(void) const
   {
     return "Foo"; // + this->member_var1 + this->member_var2...
   }
};

But depending on CharT, I have to use "", L"", u"" or "U" (for char, wchar_t, u16char_t, u32char_t).

What syntax must be used to create strings that are independed from such template arguments?