Precision generation and measurements of small static and dynamic forces by means of radiation pressure of multipass laser beam
Final Report Abstract
A high-precision table-top force measurement system (FMS) is developed for direct experimental investigations on the possibilities of using the quantum mechanical approach to generate calibration/reference forces (due to the transfer of the photon-momentum) at µN, nN and below and for their measurement by using classical mechanical principles. Ultra-high reflective mirrors with reflectivity coefficient about 0.99995 (50 ppm loses) optimized for 532 nm wavelength are employed in order to create a special macroscopic optical cavity with each mirror rigidly connected to a separate force sensor that the FMS consist. The cavity is serving to couple the complex opto-electro-mechanical based differential (for noise/common mode rejection) FMS operating in horizontal plane for 1-degree-of-freedom, with a custom developed optical layout in order to deliver laser energy to the system. Various high-power continuous wave and pulsed laser systems are employed at an average optical power levels from several mW to 20 W referenced by calibrated state-of-the-art optical power sensors in order to create specular multi-reflected laser beam configuration within the cavity (oblique incidence, avoiding creation of interference patterns or energy absorption). Due to the transfer of the photon momentum as a result of this multi-reflection process an additively built up of an amplified force values up to the 4000 nN are measured in comparison with several ten nN forces that are generated from single reflection. Theoretical computation based on simplified model that reproduces the actual measurement conditions is used for comparison of measured and calculated force values. An agreement of the measured and theoretically calculated force values is obtained to better than 1.7 % which is an improvement in comparison with the result obtained earlier of about 20 % (also known from literature). It was demonstrated through the systematic study and direct experimental evidence that the reference force values on continuous scale from several ten nN up to 4000 nN can reliably be generated dependent from the initially known values of the input power of the laser, the number of reflections and the reflectivity coefficient of the mirrors. Additionally, scientific research is conducted on various aspects of engineering/technological processes throughout complex measurement system of the FMS by which a preliminary developed metrological infrastructure is tailored. At the future works, measurements of this generated forces traceable to International System of Units (SI) and the corresponding evaluation of the measurement uncertainties will be performed.
Publications
- “Metrology in direct photon momentum measurement“, - In: Messunsicherheit - Prüfprozesse 2019. - Düsseldorf : VDI Verlag GmbH, (2019), S. 193-205
S. Vasilyan, N. Rogge, T. Fröhlich
(See online at https://doi.org/10.51202/9783181023655-193) - ”Photon momentum induced precision small forces: a static and dynamic check“, Meas. Sci. Technol. 30 105004, (2019)
E. Manske, T. Fröhlich, S. Vasilyan
(See online at https://doi.org/10.1088/1361-6501/ab257e) - “Revisiting the limits of photon momentum based optical power measurement method, employing the case of multi-reflected laser beam”, Metrologia (2020)
S. Vasilyan, M. López, N. Rogge, M. Pastuschek, H. Lecher, E. Manske, S. Kück, T. Fröhlich
(See online at https://doi.org/10.1088/1681-7575/abc86e) - “Optical power measurements via photon momentum and its comparison with SI-traceable reference methods”. 14th International Conference on New Developments and Applications in Optical Radiometry (NEWRAD 2021), June 21-24, 2021
S. Vasilyan et al.
