Patent ID: 8675702

Claim:
A laser module comprising: a fixing member; a quantum cascade laser emitting mid-infrared light of a wavelength band of 3.8 to 11.5 μm and mounted on the fixing member; a tubular member having a pair of opening ends and mounted on the fixing member so that one opening end is opposed to a face opposed to an emitting end face of the quantum cascade laser, the tubular member is comprised of stainless steel; and an infrared detector mounted on the fixing member so as to be opposed to the other opening end of the tubular member, wherein only the tubular member is arranged in an optical system between the quantum cascade laser and the infrared detector, and wherein the tubular member has a cross-sectional area set in the range of 1.23 to 2.24 mm 2 , a quantity of the mid-infrared light guided inside the tubular member is substantially independent of an oscillation center wavelength of the quantum cascade laser.