Analog, non-mechanical beam-steerer with 80 degree field of regard

Abstract

Frames from an IR video showing a 1550 nm beam scanned across a parking lot (above a seated person). ABSTRACTWe are presenting a novel electro-optic architecture for non-mechanical laser beam steering with a demonstrated 80 degrees of steering in a chip-scale package. To our knowledge this is the largest angular coverage ever achieved by non-mechanical means. Even higher angular deflections are possible with our architecture both in the plane of the waveguide and out of the waveguide plane. In the present paper we describe the steering in the plane of the waveguide leaving the out-of-plane scanning mechanism to be detailed in a subsequent publication. In order to realize this performance we exploit an entirely new electro-optic architecture. Specifically, we utilize liquid crystals (LCs), which have the largest known electro-optic response, as an active cladding layer in an LC-waveguide geometry. This architecture exploits the benefits of liquid crystals (large tunable index), while circumventing historic LC limitations. LC-waveguides provide unprecedented macroscopic (>1 mm) electro-optic phase delays. When combined with patterned electrodes, this provides a truly analog, "Snell's-law-type" beam-steerer. With only two control electrodes we have realized an 80 degree field of view for 1550 nm light. Furthermore, the waveguide geometry keeps the light from ever coming into contact with an ITO electrode, thereby permitting high optical power transmission. Finally, the beamsteering devices have sub-millisecond response times.

Liquid crystal waveguides: new devices enabled by >1000 waves of optical phase control

“…Figure 6 illustrates a few possibilities, all of which have been reduced to various levels of prototypes. [10][11][12][13] In addition to these, LC-waveguides may also be used for optical coherence tomography, true optical time delays, tunable lenses, optical switches, and many more. In the rest of this proceedings we provide some examples of new photonic devices that are enabled by LC-waveguides: i) a chip-scale non-mechanical Fourier Transform Spectrometer, ii) non-mechanical wide angle beamsteerers, iii) chip-scale widely tunable lasers, iv) ultra-low power optical switch, and v) voltage tunable micro-ring resonator.…”

“…To date we have demonstrated: ultra-wide field of view (270 o demonstrated) non-mechanical laser beamsteerers, FTIR spectrometers on a chip with < 5 nm resolution, chip-scale widely tunable lasers (nearly 40 nm tunability demonstrated), ultra-low power (< 5 μWatts) tunable micro-ring filters and Mach-Zehnder switches, and many more. [10][11][12][13] All of these devices may be in small LCD-like packages that can ultimately be as low cost as a calculator display.…”

“…Vescent's proprietary liquid-crystal (LC) waveguide architecture [5][6][7][8][9][10][11][12][13] provides unprecedented voltage control over optical phase (> 2 mm), orders of magnitude more than any other technology, e.g., liquid crystal optical phased arrays 14 or MEMs. This previously unrealizable level of control makes possible new devices with remarkable performance attributes.…”

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

“…Mechanical approaches include scanning/rotating mirrors [13], rotating prisms [14], piezo actuators [15], and micro-electromechanical system (MEMS) mirrors [16,17]. On the other hand, non-mechanical options include acousto-optic and electro-optic deflectors [18][19][20][21], electro-wetting [22][23][24][25], and liquid crystal (LC) technologies [26,27], to name a few. Although traditional mechanical beam steering devices are reasonably robust, some technical issues remain to be overcome, such as relatively short lifetimes, heavy weight, large power consumption, and high cost.…”

Simulation of electrically controlled nematic liquid crystal Rochon prism

“…The deflec− tion angles of the wedges are rather small due to small apex angles. Large deflection angles can be obtained if the light beam propagates along a thin liquid crystal layer and refracts or reflects at an oblique interface between two regions with different director orientations [9]. In this paper, we simulate numerically the nematic liquid crystal beam steering device which operates as an electrically controlled Rochon prism.…”