Beam direction-controllable surface grating-loaded VCSEL array

This paper demonstrates a beam direction-controllable slow-light vertical-cavity surface-emitting laser (VCSEL) array. By optimizing the epitaxial structure and surface grating of the rectangular VCSELs with bent waveguides, we achieved directional emission of single beams. We proved the feasibility of changing the beam deflection angle by altering the surface grating period of VCSEL through theoretical analysis and experiment. Compared to the existing scheme of steering the beam emission direction by adjusting the injected current, this approach enables a larger adjustable range for beam deflection angles of over 28°. To our knowledge, this is the largest deflection range obtained by slow-light VCSEL devices without the need for external beam-splitting components. We integrated these slow-light VCSELs with different grating periods into an array, ultimately achieving an optical beam deflection angle range exceeding 55° and a minimum far-field divergence angle of 0.58°. In addition, for a single VCSEL, a continuous variation of the deflection angle of 1.4° can be achieved by changing the injection current. This research is expected to be applied in the field of 3D sensing to achieve chip-scale direct scanning.