Abstract: A sensor-in-package device, a process for fabricating a hermetically-sealed sensor-in-package device, and a process for fabricating a hermetically-sealed sensor-in-package device with a pre-assembled hat that employ example techniques in accordance with the present disclosure are described herein. In an implementation, the sensor-in-package device includes a substrate; at least one thermopile, at least one photodetector, at least one light-emitting diode, an ultraviolet light sensor, and a pre-assembled hat disposed on the first side of the substrate, where the pre-assembled hat includes a body; a first lid; and a second lid; where the body, the substrate, and the first lid define a thermopile cavity that houses the at least one thermopile, and where the body, the substrate, and the second lid define an optical cavity that houses at least one of the at least one photodetector, the at least one light-emitting diode, or the ultraviolet light sensor.