ABSTRACT
We suggest overcoming the "Rayleigh catastrophe" and reaching superresolution for imaging with both spatially and temporally correlated field of a superradiant quantum antenna. Considering far-field radiation of two interacting spontaneously emitting two-level systems, we show that for the measurement of the temporally delayed second-order correlation function of the scattered field, the Fisher information does not tend to zero with diminishing the distance between a pair of scatterers even for non-sharp time-averaged detection. For position estimation of more scatterers, the measurement of the time-delayed function is able to provide a considerable accuracy gain over the zero-delayed function. We also show that the superresolution with the considered quantum antenna can be achieved for both near-field imaging and for estimating the antenna parameters.
ABSTRACT
Application of a metallic thin-film selector to the single-frequency oscillation of a diode-pumped Nd:YVO(4) laser has been investigated theoretically and experimentally. We show that a chromium thin-film selector with a thickness between 8 and 9 nm provides single-frequency output within a power range of 0.6 W. Single-frequency operation, slow smooth tuning, or chirping was realized by the output coupler movement with a piezoceramic transducer. Chirping at a repetition rate of 0.5 kHz in the 0.5-10-GHz range was achieved. Physical and technical limitations caused by the wide-gain bandwidth, thermal effects, and mechanical vibrations of cavity elements are discussed.
