Radiation pressure – RP phenomenon has drawn much interest since the beginning of the 20th century. There are many quantum technologies linked with it and worth mentioning like: cavity optomechanics with optical cooling and small forces amplification, single atom trapping, cantilevers spring constant calibration or high-power laser measurement.
Nevertheless, the quantitative measurement of the RP and the Photon Force – PF is always influenced by many parasitic effects e.g. photothermal effects, which can appear while the radiation beam is absorbed. The goal of the investigations presented was to design and manufacture a MEMS/NEMS tool, the so-called PF cantilever, for the reliable PF-interactions studies where the photothermal effect is highly reduced, then present the quantum mechanical reference for force/mass sensing purposes.
Cantilever as a tool for optomechanical investigation fits perfect, due to the universality of its further application. Moreover, its elasticity and mechanical behavior can be exactly described within the mechanical impedance metrology method. Some recent attempts were mainly focused on how to increase the reflectivity coefficient R. In this case double-layer dielectric coating (to avoid thermal expansion coefficient mismatch) or multilayer highly reflecting mirror application were applied. To avoid such cost- and time-consuming approaches and to eliminate theoretical considerations and measurements we propose to design of the cantilevers for PF-investigations.
The cantilevers are arranged in quadruple arrays and U-shaped which makes the spring constant lower than 0.1 N/m. Furthermore, the consequence of their stiffness is the high resolution of photon force detection lower than 100 fN/Hz1/2. The material for the construction is boron doped silicon (BDS) which makes the PF-cantilever fully conductive (entire structure forms the Lorentz loop) and thus removes the thermal actuation problem due to thermal coefficient mismatch of the current loop and beam material. By integration of the Lorentz loop it is possible to actuate the structure’s deflection and to adjust the sensor position. The force resolution resulting from the thermal limit is lower than 1 pN. Compensation of the smallest force requires biasing the loop with the current equal to about 10 nA what causes the dissipation of 10-100 fW of power).
