Tissue substance measurement systems are arranged with highly specialized
optical sources. Quantum cascade lasers are high power semiconductor
lasers which are tiny in size and highly tunable with respect to
wavelength. When deployed in non-invasive tissue substance measurement
systems, quantum cascade lasers offer system advantages such as high
accuracy, small size, convenience, efficiency, among others. These
specialized semiconductors may be used with systems based upon
photoacoustic principles. Systems may be formed of a plurality of quantum
cascade laser in an optical source, mechanism to couple light into
tissue, an acoustic detector and a signal processor. In some versions,
user interfaces provide a reporting and feedback function to a user.
