Photonic design is an important tool in modern classical and quantum optics. By controlling different degrees of freedom in photonic systems, it enables state-of-the-art devices such as mode couplers, solar cells, and computing chips. In this talk, I will show how photonic design can be applied to two problems. The first concerns maximizing motion-induced energy transfer between light and an external drive in a time-varying medium. This energy transfer sets, for example, the maximum frequency shift or field amplification in optical modulators, as well as the maximum force, torque, and work in optomechanical devices. Using a far-field scattering formalism, I model this motion-induced energy transfer in the adiabatic limit and derive the optimal temporal modulation and incident wavefront that maximize it. The second problem concerns quantum state transfer, where quantum information is transmitted from one qubit to another. This is typically done by having the first qubit emit a photon and the second qubit absorb it. Without deliberate engineering, however, the absorption probability is at most 54%. Existing solutions rely on active components to control the coupling between the qubits and the photon. Here, I will show that by engineering the photonic environment, specifically the dispersion profile of its propagating mode, one can achieve perfect quantum state transfer without any active components.