  Cat states, as an important resource in the study of macroscopic quantum
superposition and quantum information applications, have garnered widespread
attention. To date, preparing large-sized optical cat states has remained
challenging. We demonstrate that, by utilizing interaction-free measurement and
the quantum Zeno effect, even a fragile quantum microscopic system can
deterministically control and become entangled with strong light fields,
thereby generating large-amplitude optical cat states. During the entire
preparation process, our method ensures that the microscopic system functions
within a weak field environment, so that its quantum property can be protected.
Furthermore, we show that the preparation of cat states is possible even when
the quantum microsystem suffers from significant photon loss, provided that
optical losses from classical devices are kept low, which implies that the
fidelity of the cat state can be enhanced by improvements to and the perfection
of the classical optical system.
