An apparatus is provided that includes a near infrared (NIR) light emitting diode (LED) having a predominant axis of NIR light transmission from the NIR LED and a lens that disperses NIR light received from the NIR LED with respect to first and second planes, the lens having an air to lens light entry boundary where light from the NIR LED enters a surface of the lens and a lens to air boundary where the light exits the lens in each of the first and second planes, wherein an intersection formed by the second plane with the surface is a line that is concave on each side of the predominant axis, and wherein a radius of the air to lens light entry boundary of the line successively increases over each span of a predetermined number of degrees progressing outwards along the line from the predominant axis.