Fresnel Blender

Applications of this new and unique capability range from simplification (reduced element count) in ultrahigh- intensity laser installations to cylindrical focusing of excimer lasers for annealing systems, to lenses for laser-based free-space communications.

In celebration of the UNESCO International Year of Light and the 200th anniversary of Augustin-Jean Fresnel’s wave theory, the Society of Light and Lighting organised the Fresnel Lecture, with sponsorship from Philips, along with the IALD and the STLD. During the lecture, Peter Phillipson MSLL reappraised the life and work of Fresnel, along with guest appearances, artifacts and experiments.

Fresnel effect

Superior antireflection (AR) coatings are also critical for transmission gratings. PGL’s experience in thin-film coating enables us to produce our own optimized AR coatings for each transmission grating design. The resulting gratings are ideal for compact, commercial systems from laser pulse compressors to spectrometers.

Fresnel pronunciation

Fresnel lens

PGL’s grating exposure and etching processes produce exceptionally smooth, uniform, and deep grating grooves for negligible diffracted wavefront distortion and high uniformity and diffraction efficiency.

Transmission gratings require very deep groove depths to achieve high diffraction efficiency into the desired order – typically 3 – 10 times deeper than MLD and gold gratings. PGL has developed a deep etch process based on reactive ion etching (RIE) capable of attaining > 2.5 μm groove depths directly in fused silica substrates. The high uniformity of this process coupled with the precision of Scanning Beam Interference Lithography implemented in PGL’s Nanoruler grating writing technology leads to exceptional Diffracted Wavefront Error performance.

Focusing Gratings In addition to the many advantages of PGL’s SBIL grating writing technology for standard gratings – high diffraction efficiency, consistent duty cycle, and period repeatability of 10 ppb from part-to-part – the Nanoruler also can readily produce curved grating lines. As a result, we can produce both spherically and cylindrically focusing gratings.

The plot below shows the theoretical diffraction efficiency vs. input wavelength and angle of incidence for a 1,200 l/mm grating optimized for 800 nm. Actual gratings typically have DE 1 – 2% below theory.

Fresnel Light

A type of lantern which produces an even, soft-edged beam of light through a Fresnel lens. The lens is a series of stepped concentric circles on the front and pebbled on the back and is named after its French inventor, Augustin Jean Fresnel (1788-1827). He developed the lens for French lighthouses so that they could be seen further out to sea and could achieve a longer focal length with a lot less glass than a standard plano-convex lens.

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