The ability to “see” in the infrared spectral region provides rich information on thermal and chemical signatures enabling applications in night vision, thermography, healthcare, astronomy, surveillance, climate studies, and more. There is a continual desire to improve the technology of infrared detectors for imaging systems to improve performance, incorporate spectral selectivity, and to reduce the size, weight, and power of systems. In this presentation, infrared detector technology concepts will be presented along with select recent research topics on infrared detectors in our research group. These topics include novel HgCdTe detector device structures to reduce dark current, InGaAs/GaAsSb type-II superlattices on InP for SWIR detection, and subwavelength optical gratings for infrared spectral filtering. In addition, biological tissue has an optical transparency window in the near-infrared, providing an opportunity for wireless power transfer and communications for bioimplantable devices. Efficient mm-scale near-infrared energy harvesting devices will be presented, which may ultimately enable implantable biosensors for cancer treatment and neural interfaces.