Patents

We have a series of patents related to the Moiré Diffractive Optical Elements (MDOEs):

MDOEs are pairs of diffractive optical elements which can act as tunable Fresnel lenses, axicons or other optical elements upon mutual rotation.

Principle

DOE-Grafik

Short Demo Video
(AVI, ~40MB)

Info-Flyer
(pdf)

Two specially designed diffractive optical elements (DOEs) are placed very closely behind each other. A rotation of one element around the central axis leads to a Moiré pattern which determines the optical properties of the joint DOE.

Optical elements with properties that are continuously adjustable by a mutual rotation include:

varifocal diffractive lenses
flat zoom lenses
axicons with a variable refractive power (for applications as beam couplers in fiber optics),
continuous phase shifters (for applications in interferometers or frequency sideband generation),
spiral phase plates with a variable helical index (for holographic optical tweezers to produce doughnut beams or for spiral phase contrast in optical microscopy).

More details on MDOEs

Application scenarios for varifocal Fresnel lenses:

Advantages of MDOEs:

human-eye-like imaging systems
lenses in environments with restricted space (cell phones etc.)
inspection systems (continuous distance scanning)
laser scan heads (fast z-control, high damage threshold)
collimation lenses in illumination systems (overhead projection, microscope illumination)
for flashlight focusing
for adjustable eyeglasses
as multi-purpose lenses for experimental setups in research laboratories, optical development, and prototyping.

very wide range of focal lengths adjustable with a single MDOE
diffraction limited point-spread-function
lightweight optics
thin (entire element can be less than 1 mm thick)
can be used for both, micro-optics and large scale lenses (e.g. overhead projector lenses)
compatible with high laser power
no position change of optics necessary to change the focal length
dispersion of diffractive element may counteract dispersion of refractive elements (e.g. when combined with a plano-convex lens).

Publication(s):

N. Bregenzer, T. Öttl, M. Zobernig, M. Bawart, S. Bernet, and M. Ritsch-Marte: Demonstration of a multi-color diffractive lens with adjustable focal length., Optics Express 28, 20, 30150 (2020)

M. Bawart, N. Bregenzer, S. Bernet, M. Ritsch-Marte Dynamic beam steering by a pair of rotating diffractive elements, Opt. Commun. 460, 125071 (2020)

Stefan Bernet and Monika Ritsch-Marte, "Multi-color operation of tunable diffractive lenses," Opt. Express 25, 2469-2480 (2017).

M. Bawart, Jesacher A., Zelger P., Bernet S., Ritsch-Marte M., Modified Alvarez lens for high-speed focusing, Opt. Express 25, 29847-29855 (2017)

Walter Harm, Stefan Bernet, Monika Ritsch-Marte, Irina Harder, and Norbert Lindlein, Adjustable diffractive spiral phase plates, Opt. Express 23, 413-421 (2015).

Walter Harm, Clemens Roider, Alexander Jesacher, Stefan Bernet, and Monika Ritsch-Marte, "Dispersion tuning with a varifocal diffractive-refractive hybrid lens," Opt. Express 22, 5260-5269 (2014).

Stefan Bernet, Walter Harm, and Monika Ritsch-Marte, Demonstration of focus-tunable diffractive Moiré-lenses, Optics Express, Vol. 21 Issue 6, pp.6955-6966 (2013)

Stefan Bernet and Monika Ritsch-Marte, Adjustable refractive power from diffractive moiré elements, Applied Optics 47, 3722-3730 (2008)

Coverage in Optoelectronic News World and Laser Focus World

Filed patent applications

2019

S. Bernet, M.Bawart, M. Ritsch-Marte „Optical system for light steering“, EP-application 19 19 3442.1
M. Bawart, N. Bregenzer, S. Bernet, M. Ritsch-Marte Dynamic beam steering by a pair of rotating diffractive elements, Opt. Commun. 460, 125071 (2020)
status: pending

2017

M. Bawart, S. Bernet, A. Jesacher „Modified Moiré Lens,“ EP application.
M. Bawart, Jesacher A., Zelger P., Bernet S., Ritsch-Marte M., Modified Alvarez lens for high-speed focusing, Opt. Express 25, 29847-29855 (2017)
status: pending

Awards

Prototypenförderungspreis

Grand Prix at the South Korean Inventors’ Fair KIWIE 2011 (Press release)