High efficiency multiple beam gratings

Abstract

Diffraction gratings are used in many optical systems as beam splitters. In these applications the diffraction grating must (1) have high diffraction efficiency and (2) produce uniform intensities in the central block of diffracted beams. High diffraction efficiency is attained by making the grating a phase grating. In this paper we discuss in some detail the use of pulse width modulation (PWM) and pulse position modulation (PPM) to create grating structures that produce uniform central diffracted beams. By using these modulation techniques and proper phase relief for the grating, the diffraction grating can have a diffraction efficiency of 70% or more. Some examples of multiple beam diffraction gratings produced by using PWM and PPM are shown.

Quantum Information with Structured Light

“…Therefore, the phase and the amplitude of the diffracted light can be controlled by setting the parameters p(x) and w(x). In the language of communication theory, these methods are sometime referred to as pulse position modulation (PPM) and pulse width modulation (PWM) [92,93]. Eq.…”

Generating stable tractor beams with dielectric metasurfaces

“…The designed metasurface consists of a Si bullseye pattern on a bulk SiO 2 substrate. Inspiration for this geometry is derived from the extensive literature on binary phase gratings, which are commonly employed for interfering plane waves due to their simple design and fabrication processes [39][40][41]. The period of the grating determines the angles at which light will be transmitted, and the thickness of the Si determines the efficiency.…”

Experimental generation of an optical field with arbitrary spatial coherence properties

“…A shift in the location of these pulses will change the overall phases into the diffracted orders, while changing the widths or duty cycles of the pulses will change the diffracted efficiency. These two methods are known as pulse position and pulse width modulation respectively [24,26,27], and such a modulation represents a generalization of the Moiré technique [28]. Mathematically, a periodic binary grating can be written as a Fourier series…”