While quantum and nonlinear photonic technologies are typically developed at shorter wavelengths, there are significant opportunities associated with moving to longer wavelengths. They are particularly valuable for sensing, classical and non-classical: mid-infrared’s ability to act as a molecular fingerprint holds promise for portable medicine, longwave infrared LIDAR can penetrate greater distances in inclement weather, and terahertz can noninvasively detect complex molecules such as explosives. It is it not only important to develop existing concepts at longer wavelengths, but it is also important to take advantage of the opportunities for when longer wavelengths enable new conceptual advances.