Lidar and related applications continue to present an unsatisfied need in broadband, random access, non-mechanical beam steering devices. A conformal, thin, broadband and rapid beam steering device is thought of as a vehicle to overcoming the recognized disadvantages of traditional optical systems and electro-optical beam steering devices, which use heavy and power-hungry gimbals and optical components making large mechanical motions. While various non-mechanical optical beam steering devices have been demonstrated, most of such devices utilize electrically-controlled optical diffraction elements such as, for example, an LCoS (that is, a liquid-crystal-on-silicon) based contraption and/or a MEMS (micro-electro-mechanical) based system to steer the optical beam in space. Each of these elements represents an actively-operated (or active) diffractive element. These spatial light modulator (SLM) devices normally operate over a corresponding narrow wavelength band (referred to herein interchangeably as “wavelength spectrum” or simply “spectrum” of operation of the device). Since the diffraction-effect-induced steering angle (θd) relates to the wavelength of the incident light (λ) via the grating equationsin θd−sin θi=mλΛ  (1),
where θi is the incidence angle, m an integer number defining the diffraction order, and Λ is the grating spacing (period), the polychromatic light diffracted upon interaction with (or at) such device is spatially dispersed, as is schematically illustrated in FIG. 1. Put differently, the polychromatic light is spread angularly in accordance with its spectral contents.
The observed effect of dispersion can be expressed, based on the grating equation, asdλ/dθd=Λ cos θd/m  (2)
This fundamental property that polychrotnatic light disperses angularly upon interaction with an active diffractive element, according to spectral contents of polychromatic light inevitably limits the operation of any diffraction-based beam-steering device to narrow spectral band applications.
Considering that new types of laser sources—such as, for example, frequency comb pulsed lasers and supercontinuum lasers—require spectrally-broadband operation (in order to effectuate, for example, hyperspectral light detection and ranging, LIDAR, systems), the availability of broadband-spectrum-adapted beam-steering devices capable of supporting the required spectrally-broadband operation of the laser light source may facilitate the enablement of new LIDAR applications.
USPTO Backgrounds
USPTO Backgrounds