A body monitor (12) for monitoring a condition of a living being (10) includes (i) a monitor housing (28) that is positioned adjacent to the living being (10)； (ii) a first laser source (240) that directs a first output beam (240A) at the living being (10) to generate first photoacoustic waves； (iii) a second laser source (242) that directs a second output beam (242A) at the living being (10) to generate second photoacoustic waves； and (iv) a photoacoustic detector (16) secured to the monitor housing (28). The photoacoustic detector (16) detects the first photoacoustic waves and the second photoacoustic waves to monitor the condition of the living being (10). The output beams (240A) (240B) have a different center wavelength and can be in the mid-infrared range.
