Low-Cost Scanning Beam Profiler Architectures for Near-Infrared Laser Characterization: Experimental Validation and Comparative Simulation

We present a low-cost beam profiling system based on a rotating photodiode detector for the characterization of near-infrared laser beams. Commercial beam profilers operating in this wavelength range are often costly and rely on specialized detector arrays with a limited wavelength range, while common silicon cameras are insensitive above 1.1 μm. The proposed system employs a single photodiode on a rotating arm, digitized by a microcontroller-based platform, enabling one-dimensional reconstruction of the beam intensity distribution at substantially reduced cost and complexity. Experimental validation at 1550 nm demonstrates approximately 10% agreement with a commercial Thorlabs scanning-slit beam profiler over the observed operating range, where the beam diameter spans at least three detector aperture widths. This agreement is comparable to the manufacturer-specified accuracy of commercial scanning-slit profilers, while the proposed system costs approximately one-twentieth as much. The wavelength coverage can also be extended from 800 to 2600 nm through detector substitution alone. Two alternative architectures are introduced through simulation: a single-mirror galvanometer for high-speed one-dimensional scanning, and a hybrid rotating-arm plus galvanometer system that combines two orthogonal one-dimensional scans to achieve full two-dimensional beam reconstruction.