Yves Jourlin

Spatially and polarization resolved plasmon mediated transmission through continuous metal films

The experimental demonstration and characterization is made of the plasmon-mediated resonant transmission through an embedded undulated continuous thin metal film under normal incidence. 1D undulations are shown to enable a spatially resolved polarisation filtering whereas 2D undulations lead to spatially resolved, polarization independent transmission. Whereas the needed submicron microstructure lends itself in principle to CD-like low-cost mass replication by means of injection moulding and embossing, the present paper demonstrates the expected transmission effects on experimental models based on metal-coated photoresist gratings. The spectral and angular dependence in the neighbourhood of resonance are investigated and the question of the excess losses exhibited by surface plasmons is discussed.

100 nm period grating by high-index phase-mask immersion lithography

The interferogram of a high index phase mask of 200 nm period under normal incidence of a collimated beam at 244 nm wavelength with substantially suppressed zeroth order produces a 100 nm period grating in a resist film under immersion. The paper describes the phase mask design, its fabrication, the effect of electron-beam lithographic stitching errors and optical assessment of the fabricated sub-cutoff grating.

A monolithic optical phase-shift detector on silicon

A novel monolithically integrated device used as an optical phase-shift detector is presented. It consists of a diffraction grating etched at the surface of a p-n photodiode fabricated by a process compatible with a standard silicon CMOS technology. When two coherent light beams are collimated toward the surface of the device, the detected optical power generates a current depending on the relative phase between the two incident beams. The operating principle of this detector and the results obtained by finite-difference time-domain modeling are presented. The fabrication process of the first devices is described and the experimental validation of the concept is demonstrated.

Fast dynamic interferometric lithography for large submicrometric period diffraction gratings production

Abstract. This paper describes a successful technological transfer, from a state laboratory to an industrial company, for writing long and large submicron period gratings (potentially square-meter sized), implemented in an industrial direct laser beam writing equipment at 355 nm wavelength (Dilase 750 from KLOE SA company). The writing head, which has been inserted in the machine, consists of a phase mask which enables it to project a set of fringes pattern of small area onto a photoresist-coated substrate. As the substrate is continuously moving, one-dimensional or two-dimensional gratings can be fabricated over large areas limited only by the machine’s stage displacement range. The optical scheme is described from the beam shaping to the printing processes and the phase mask optimization. In order to demonstrate the technology, 600 nm period gratings of over 20 cm in length have been fabricated. Such submicron structures can be used in solar cell modules for photon trapping and as antireflection coatings.

Subwavelength cylindrical grating by holistic phase-mask coordinate transform

A periodic grating with an integer number of periods is fabricated at the resist-coated wall of a cylinder by exposing a circularly symmetrical planar high index phase mask to a cylindrical wave. This extends the spatial coherence features easily achievable in a planar 2D space to the 3D space of cylindrical waves and elements.

On-the-fly writing of a long grating phase mask

A method is demonstrated for writing long grating phase masks, which can be used for patterning large-area (square meter size) submicron-period gratings. The method consist of illuminating a small area transmission grating phase mask by a continous wave transverse-electric-polarized collimated laser beam under the −1st order Littrow mounting to define a high-contrast interferogram composed of fringes. By sliding a long photoresist-coated substrate under this small area phase mask, gratings of arbitrary length may be written, with grating lines oriented in the scan direction. The patterning of uninterrupted gratings with lengths exceeding 300 mm is demonstrated.

Sharp Plasmon-Mediated Resonant Reflection From an Undulated Metal Layer

A close-to-the-theoretically-largest TM resonant reflection of a free-space wave from a free-standing undulated gold layer immersed in a liquid host medium is demonstrated experimentally. It is mediated by the grating-excited long-range plasmon mode propagating along the continuous metal film with particularly low loss.

Resonant-grating reflection extended to wide-band, large-aperture beams by waveguide-mode coalescence

The resonant reflection of a free-space beam from a slab waveguide grating is rendered high bandwidth and angularly robust by using a bimodal high index waveguide. A deep double-sided corrugation gives rise to the coalescence of the resonant reflection peaks resulting in a top-hat reflection spectrum. A low-cost waveguide technology based on solar cell amorphous silicon is demonstrated in the near infrared in a polarizer application.

Cylindrical Grating Projection by Single-Shot Normal Exposure of a Radial Phase Mask

A periodic grating is defined at the photoresist-coated wall of a circular cylinder with an integer number of particularly long grooves parallel to the generic lines by the holistic exposure of a radial phase mask to a normally incident collimated laser beam. The single-shot projected element corresponds to the inner grating of a high-resolution miniature shaft encoder.

Monolithic double-grating phase mask for large-period highly coherent grating printing

A monolithic double-grating phase mask comprising three short-pitch grating sections of spatial frequencies k(1) and k(2) collocated at one side of a substrate produces a large-period interferogram without higher harmonics to print in a photoresist film a latent grating of small spatial frequency equal to twice k(2)-k(1). When incorporated in a write-on-the-fly scheme, the elements permit the fabrication of unlimitedly long gratings.