1. A device comprising:a light source assembly; and
a control system configured to cause the light source assembly to perform functions comprising:
emitting a first light having a first luminous flux and a peak intensity at a first wavelength that is greater than or equal to 680 nanometers (nm) and less than or equal to 750 nm, wherein the first luminous flux oscillates at a first frequency; and
emitting a second light having a second luminous flux and a peak intensity at a second wavelength that is less than or equal to 680 nm, wherein the second luminous flux (i) oscillates at a second frequency that is equal to the first frequency and (ii) is out of phase with the first luminous flux.