Continuous wave Bessel beams with a strong longitudinal acceleration in free space

A variety of transversely accelerating optical beams, such as Airy, Mathieu, and Weber have been proposed intensively studied in the past few decades, while longitudinal acceleration beams free space has considered much less mostly for ultrashort pulses. In this work, we create two-component continuous wave Bessel that exhibit extremely high space, with group velocity changing by a factor 10 just centimeters propagation. The beam components are co-propagating interfering can different frequencies angular spectra. We also demonstrate large-magnitude negative velocities zero-group-velocity modes beam. measured interferometrically, using common-path interferometer. measurement results agree well theoretical predictions. presented methods to control measure light expected attract attention researchers working on interferometry, ultrafast optics, nonlinear tweezers.