We have common detectors for radio, microwaves, visible, ultraviolet, xray and gammy rays.. but how about the infrared frequencies from molecular vibrations. The frequencies of molecular vibrations range from less than 10^12 to approximately 10^14 Hz. These frequencies correspond to radiation in the infrared (IR) region of the electromagnetic spectrum. How come we don't commonly heard of detectors of it? I'm not talking about Raman Spectroscopy, but just plain detectors.. why can't we detect molecular vibrations frequencies yet we can easily detect radio, microwave, xray, etc.? anything I missed?