“…In addition to the above aspects, TO has many other applications, such as calculating the optical force, designing gratings, designing spontaneous emissions, reverse ray tracings, designing perfect matched layers in numerical simulations, etc. In recent years, more and more new branches are emerging from TO, such as TO with graphene, TO with photonic crystals, TO with meta‐surfaces, TO with Fourier optics, TO for lossy media by complex coordinate transformations, etc.…”