filtered light 548 is directed onto flipper mirror 700 positioned in the up position an actuator is mounted to flipper mirror 700 to lower and raise flipper mirror 700 between a first down position as shown in fig9 and a second up position as shown in fig1 in the first position flipper mirror 700 does not receive filtered light 548 which is instead received by optical element 514 which reflects filtered light 548 into accessory compartment 300 to form light 516 in the second position flipper mirror 700 is positioned to receive filtered light 548 and to reflect the received filtered light 548 toward optical element 802 and the crystal such that optical element 514 does not receive filtered light 548 or form light 516 optical element 802 receives light reflected from flipper mirror 700 and reflects the received light toward first optical element 1102 first optical element 1102 receives light reflected from optical element 802 and reflects the received light toward a lower surface 1200 shown with reference to fig1 of atr puck 702 atr puck 702 is formed of an optically dense crystal with a high refractive index at a certain angle this internal reflectance creates an evanescent wave that extends beyond the surface of the crystal and into the sample held in contact with the crystal this evanescent wave protrudes a few microns beyond the crystal surface.