Fig. 1
From: Optical excitation of atomic force microscopy cantilever for accurate spectroscopic measurements
Schematic diagram of the experimental setup. Two laser lights from Laser diode 1 (1550 nm) and Laser diode 2 (1310 nm) are combined with a filter Wavelength Division Multiplexer (FWDM). The combined light is launched into a single-mode optical fiber. While a fraction of the light is reflected at the fiber-vacuum interface, the rest of the light which comes out of the fiber is reflected on the back side of the cantilever and goes back into the fiber. Only the 1550 nm laser can pass through the filter WDM and reach the photo diode