Liquid crystal clad waveguide laser scanner and waveguide amplifier for LADAR and sensing applications

Abstract

We will describe the construction and performance of a prototype high speed, non-mechanically scanned, laser system that is coupled to a custom planar waveguide optical amplifier. The system provides high speed (10 kHz) scanning of >200 far-field resolvable spots, with a path toward >500 spots at 10 kHz demonstrated. An enabling component for this system is the new EO scanner that provides previously unrealizable performance such as sub-millisecond scanning, full 2-D operation with only three control electrodes, fully refractive (no side-lobes) scanning, no blind spot within the field of view (FOV), and a large continuous scan angle. Scanners with near perfect Gaussian output beams, throughputs greater than 50%, and a 50 0 × 15 o continuous field-of-view will be discussed. Furthermore, a path toward much larger FOVs will also be presented. We will also present the design and construction of custom planar waveguide amplifiers to which our EO scanner can be free space end-fire coupled. The amplifiers and scanners were designed for operation at 1.645 microns. This will enable long-range, eye-safe LADAR and sensing applications, such as CH4 sensors.

Liquid Crystal Beam Steering Devices: Principles, Recent Advances, and Future Developments

“…The major losses are from the Fresnel loss upon refractions and some in-coupling and out-coupling losses. However, as demonstrated, a waveguide amplifier can compensate for the losses [56]. The aforementioned systems work for near-infrared and short-wave infrared.…”

“…For instance, combining an OPA with several PBDs and PVGs is a common approach to fulfill these requirements. Other methods have also been demonstrated, such as combining LC-waveguide scanners with PBDs [56]. Such a hybrid device will, undoubtedly, increase the driving complexity and device bulkiness.…”

5.4: An active approach of TFT matrix controlling for liquid crystal cladding based beam steering device

“…(2)(3)(4) Due to the existence of physical momentum, such mechanical laser sweeping method has its natural limitations in several aspects. (2,5,6) Therefore, alternative solutions are highly demanded. Among those new rising technologies (7)(8)(9)(10)(11), liquid-crystal-based beam steering devices have been demonstrated and believed to be rather promising for the commercialization in terms of its cost and technology compatibility.…”

“…Among those new rising technologies (7)(8)(9)(10)(11), liquid-crystal-based beam steering devices have been demonstrated and believed to be rather promising for the commercialization in terms of its cost and technology compatibility. (5,12,13) From the work of S.R. Davis et al, (13) a prototype with such unique architecture was firstly exhibited, as illustrated in Figure 1.…”

“…The working principle of such device results in several merits, namely, faster scanning rate (more than 10 kHz), compatible with the existing display industry. (5,6,13,14) Figure 1. Crossection view of beam steering device based on liquid crystal cladding layer.…”