Self-mixing imaging sensor using a monolithic VCSEL array with parallel readout.

The advent of two-dimensional arrays of Vertical-Cavity Surface-Emitting Lasers (VCSELs) opened a range of potential sensing applications for nanotechnology and life-sciences. With each laser independently addressable, there is scope for the development of high-resolution full-field imaging systems with electronic scanning. We report on the first implementation of a self-mixing imaging system with parallel readout based on a monolithic VCSEL array. A self-mixing Doppler signal was acquired from the variation in VCSEL junction voltage rather than from a conventional variation in laser power, thus markedly reducing the system complexity. The sensor was validated by imaging the velocity distribution on the surface of a rotating disc. The results obtained demonstrate that monolithic arrays of Vertical-Cavity lasers present a powerful tool for the advancement of self-mixing sensors into parallel imaging paradigms and provide a stepping stone to the implementation of a full-field self-mixing sensor systems.