An imaging system comprising: a first laser (11, 31, 71) that emits a beam of linearly polarized light having a propagation direction; a first wire-grid polarization filter having a first linear polarization pass direction and a first actuator for causing said first linear polarization pass direction to rotate relative to said beam of linearly polarized light, said first wire-grid polarization filter being positioned such that said beam of linearly polarized light passes through said first wire-grid polarization filter; a second wire-grid polarization filter having a second linear polarization pass direction and a second actuator for causing said second linear polarization pass direction to rotate relative to said beam of linearly polarized light, said second wire-grid polarization filter being positioned such that said beam of linearly polarized light passes through said second wire-grid polarization filter after passing through said first wire-grid polarization filter; a controller for setting said first and second linear polarization pass directions to provide linearly polarized light having a specified polarization direction; a second laser that emits a beam of linearly polarized light, said second laser emitting light in a different band of wavelengths than said first laser; a beam director that causes light from said second laser to enter said first wire-grid polarization filter on a path that is coincident with a path that light from said first laser follows through said first wire-grid polarization filter; and a polarization analyzer and a first light detector, wherein the first and the second lasers are quantum cascade lasers (31, 71, 72) configured to be pulsed at different pulse rates such that said controller causes said polarization analyzer and said first light detector to measure an intensity of light for a plurality of different first and second linear polarization pass directions at multiple wavelengths at the same time. a first laser (11, 31, 71) that emits a beam of linearly polarized light having a propagation direction; a first wire-grid polarization filter having a first linear polarization pass direction and a first actuator for causing said first linear polarization pass direction to rotate relative to said beam of linearly polarized light, said first wire-grid polarization filter being positioned such that said beam of linearly polarized light passes through said first wire-grid polarization filter; a second wire-grid polarization filter having a second linear polarization pass direction and a second actuator for causing said second linear polarization pass direction to rotate relative to said beam of linearly polarized light, said second wire-grid polarization filter being positioned such that said beam of linearly polarized light passes through said second wire-grid polarization filter after passing through said first wire-grid polarization filter; a controller for setting said first and second linear polarization pass directions to provide linearly polarized light having a specified polarization direction; a second laser that emits a beam of linearly polarized light, said second laser emitting light in a different band of wavelengths than said first laser; a beam director that causes light from said second laser to enter said first wire-grid polarization filter on a path that is coincident with a path that light from said first laser follows through said first wire-grid polarization filter; and a polarization analyzer and a first light detector, wherein the first and the second lasers are quantum cascade lasers (31, 71, 72) configured to be pulsed at different pulse rates such that said controller causes said polarization analyzer and said first light detector to measure an intensity of light for a plurality of different first and second linear polarization pass directions at multiple wavelengths at the same time.