Until relatively recently, high-resolution infrared spectrographs could examine only tiny portions of individual spectral windows in a single exposure.  Silicon immersion gratings, combined with sensitive, large-format IR detectors have made it possible to observe broad swaths of the IR at once at very high resolution and to do so on much fainter systems.  We discuss the development of Si diffractive optics and of the H and K spectrograph IGRINS (now in use on the Gemini South Telescope) and the Giant Magellan Telescope Infrared Spectrograph, which will observe from 1.08 μm to 5.4 μm at R=λ/Δλ=65,000-85,000 in a single exposure.  We present results from IGRINS that demonstrate its sensitivity and versatility as it sheds new light on the atmospheres of exoplanets and cool brown dwarfs, on the evolution of YSO’s and on the physics of the ISM.