Optical atomic clocks are the most precise measurements ever build by the mankind. Accuracy at the level of 10^-18 [1,2] and instability in mid 10^-17 after 1 s of averaging  was already presented. With all perturbation under control one can use a clock not only for precise time measurements but also for other physical quantity measurements, e.g. for looking for fundamental constants variations  or dark matter in form of topological defects . Atomic clocks are also directly sensitive to the gravitational potential, i.e. they can be used as a gravitational waves detectors  and in relativistic geodesy [7,8].
All modern optical atomic clocks are passive, with an oscillator in the form of ultra-stable laser and a frequency discriminator in the form of cold atomic sample. We would like to propose instead an active optical atomic clock  as a gravitational detector. Such an active frequency standard would take advantage form both better instability and higher time resolution over already existing optical clocks. Its construction will provide a high degree of mobility, since its performance would not be limited by an instability of a fragile optical cavity.
We will present potential advantages of using active optical clocks as gravitational potential detectors along with gravimeters measuring acceleration. A combination of both devices can remotely detects not only small gravitational anomalies or objects, but also precisely locate them. Moreover, shape and mass distribution can also be derived.
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Marcin Bober and Michal Zawada, "Active optical atomic clock for gravitational anomalies detection (Conference Presentation)," Proc. SPIE 10438, Emerging Imaging and Sensing Technologies for Security and Defence II, 104380H (Presented at SPIE Security + Defence: September 14, 2017; Published: 19 October 2017); https://doi.org/10.1117/12.2277402.5618116230001.
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Study of self-shadowing effect as a simple means to realize nanostructured thin films and layers with special attentions to birefringent obliquely deposited thin films and photo-luminescent porous silicon