Simultaneous generation of N coherent pulses of various areas under self-diffraction in87Rb vapors

Abstract

Subject of study. The self-diffraction process of a resonant pulse in a dense extended resonant medium was studied for the first time to our knowledge. This process leads to an angular deflection of the output radiation and sequential emission of a large series of N pulses with a variable area in the range (−3π,…,0,…,3π). The pulses are emitted from a small focusing region (0.1–1 mm) of the pump pulse in a dense extended resonant medium. The pulse wavelength corresponds to the resonant transition D287Rb (wavelength 780.24 nm). Aim of study. The nonlinear effect of the self-diffraction of a laser pulse with a cylindrical wavefront is studied in an extended resonant medium of rubidium vapor to develop new resonant microwave photonics devices using laser signal-processing methods in the microwave spectrum. Method. A transverse spatial profile of the electric field strength of a special shape f(x) is created in the caustic of a focused beam of a laser pump pulse with a cylindrical wavefront. The pump pulse must have a converging (for example, cylindrical) wavefront. Computer-synthesized holograms developed by us are used to create an arbitrary f(x) profile. Main results. The effect of the self-diffraction of a pump pulse is studied. This is accompanied by the emission of a series of N coherent resonant pulses with different areas in the range (−3π,…,0,…,3π) from a short focusing region (0.1–1 mm) of a resonant laser pump pulse. The self-diffraction of the pump pulse resulted in 16 emitted pulses with different areas. The distribution of series pulses over the diffraction angle was observed in the angle range from −5∘ to +4∘. The nonlinear generation of 0π-pulses was observed at some angles. The results verify the nonlinear generation of 0π-pulses over a short interaction length between light and a resonant medium for the first time to our knowledge. Practical significance. The obtained results on the effect of the self-diffraction of a resonant pulse with a transverse spatial profile f(x) will serve as a basis for the development of prototype devices for signal-processing problems using low-power laser diodes.