The recent development of the Micro Electromechanical System (MEMS) Phase Light Modulator (PLM) enables fast laser beam steering for lidar applications by displaying a Computer-Generated Hologram (CGH) without employing an iterative CGH calculation algorithm. We discuss the application of MEMS PLM (Texas Instruments PLM) for quasi-continuous laser beam steering by deterministically calculated CGHs. The effect on the diffraction efficiency of PLM non-equally spaced phase levels was quantified. We also address the CGH calculation algorithm and an experimental demonstration that steered and scanned the beam into multiple regions of interest points, enabling beam steering for lidar without sequential raster scanning.
Enabling all-day-wearable augmented reality (AR) displays require compact engineering solutions that still satisfy requirements like wide field-of-view (FOV) and high resolution. By using a Digital Micromirror Device (DMD) and a pulsed laser in synchronization we are able to perform diffractive image steering which decouples the FOV of the projected image from the display size while not sacrificing image resolution. This approach reduces, by several factors, the lateral extent of the display panel while retaining image resolution. The diffractive-steering-enabled FOV expansion by the DMD, paired with a prism array placed at the exit pupil of the projection lens, maintains a small form factor by re-distributing a part of the volume from the projector engine to the image transfer optics. Together with diffractive image steering and the prism array we demonstrate a 5x increase in field-of-view. This approach decreases the requirement on the number of pixels to maintain high resolution across a wide FOV, which makes it suitable for eventually installing it in small form factor head mounted displays.
Real-time, simultaneous, and adaptive beam steering into multiple regions of interest replaces conventional raster scanning with a less time-consuming and flexible beam steering framework, where only regions of interest are scanned by a laser beam. CUDA-OpenGL interoperability with a computationally time-efficient computer-generated hologram (CGH) calculation algorithm enables such beam steering by employing a MEMS-based phase light modulator (PLM) and a Texas Instruments Phase Light Modulator (TI-PLM). The real-time CGH generation and display algorithm is incorporated into the beam steering system with variable power and scan resolution, which are adaptively controlled by camera-based object recognition. With a mid-range laptop GPU and the current version of the MEMS-PLM, the demonstrated scanning speed can exceed 1000 points/s (number of beams > 5) and potentially exceeds 4000 points/s with state-of-the-art GPUs.
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