A document, product, or package, such as a banknote, passport or the like comprises structures having dichroic effects that change color with viewing angle in both transmission and reflection. Such structures can be useful as security features that counter the ability to effectively use counterfeit documents, products, packages, etc.

Disclosed are transparent energy relay waveguide systems for the superimposition of holographic opacity modulation states for holographic, light field, virtual, augmented and mixed reality applications. The light field system may comprise one or more energy waveguide relay systems with one or more energy modulation elements, each energy modulation element configured to modulate energy passing therethrough, whereby the energy passing therethrough may be directed according to 4D plenoptic functions or inverses thereof.

A laser interference lithography system with flat-top intensity profile comprises a laser source for emitting a coherent laser beam, a first beam expander for adjusting the coherent laser beam size, a refractive beam shaper for converting a Gaussian intensity profile inherent to the coherent laser beam into a flat-top one and outputting a first collimated laser beam, a second beam expander for receiving the first collimated laser beam and outputting a second collimated laser beam, a sample holder for holding a substrate, and at least one reflector for reflecting the second collimated laser beam to generate a third collimated laser beam. The second and third collimated laser beams are transmitted to the substrate at a predetermined angle to create an interference pattern exposed onto the substrate.

According to an embodiment of the present inventive concept there is provided an arrangement 4 comprising: an optical device 8 including a radially inner beam forming portion 10 and a radially outer portion 12, at least partly enclosing the radially inner portion 10. The arrangement 4 further comprises a reflector 6 arranged to reflect, in a first direction towards the radially outer portion 12, light emitted by a light source 2 such that a first optical path is formed from the light source 2 to the radially outer portion 12, via the reflector 6. The radially outer portion 12 is transparent such that incident light reaching the radially outer portion 12 along the first optical path exits the radially outer portion 12 in a direction parallel to the first direction, and at least one of scattering and attenuating for light reaching the radially outer portion 12 along a second optical path extending directly between the light source 2 and the radially outer portion 12. The radially outer portion 12 may thus act as a clear exit window for reflected light R, contributing to the intensity of a central beam F formed by the radially inner beam forming portion 10, while preventing transmission of direct light D which otherwise could produce glare.

A microscope has a light source for generating a light beam having a wavelength, λ, and beam-forming optics configured for receiving the light beam and generating a Bessel-like beam that is directed into a sample. The beam-forming optics include an excitation objective having an axis oriented in a first direction. Imaging optics are configured for receiving light from a position within the sample that is illuminated by the Bessel-like beam and for imaging the received light on a detector. The imaging optics include a detection objective having an axis oriented in a second direction that is non-parallel to the first direction. A detector is configured for detecting signal light received by the imaging optics, and an aperture mask is positioned.

A spatial frequency filter device is for use with a laser beam. The device includes: a neutral region, which is configured to transmit or reflect the laser beam; and a deflecting region, which radially adjoins the neutral region and is configured to deflect beam components of the laser beam from a beam axis of the laser beam. The deflecting region has a constant portion, in which a deflecting effect on the beam components of the laser beam for each location in the constant portion is configured to be independent of a distance of a location from the neutral region. the deflecting region has a variation portion, in which the deflecting effect on the beam components of the laser beam is configured to vary, dependent on a distance from the neutral region.

A high resolution inspection apparatus using a terahertz Bessel beam. The high resolution inspection apparatus comprises a terahertz wave generating unit for generating a terahertz wave; a Bessel beam forming unit for generating a terahertz Bessel beam using the terahertz wave incident from the terahertz wave generating unit; a ring beam forming unit for forming a ring beam using the terahertz Bessel beam and concentrating the formed ring beam to an inspection target object; a scattered light detecting unit for detecting scattered light generated from the inspection target object; and a ring beam detecting unit for detecting a ring beam transmitted through the inspection target object.

The invention relates to a light module including a semiconductor laser element emitting a laser beam in a first cone of light, a photoluminescent element, and an optical means for transforming the light coming from the photoluminescent element into an exit light beam. The optical means has a guiding portion arranged to guide at least a portion of the light emitted in the first cone of light into a second cone of light and a device for detection of incident light. The light module comprises a means of deviation designed to deviate the light of the second cone of light toward a third cone of light directed toward the detection device arranged outside of the second cone of light.

For material processing of a material, which is in particular for a laser beam to a large extent transparent, asymmetric shaped modifications are created transverse to the propagation direction of the laser beam. Thereby, the laser beam is shaped for forming an elongated focus zone in the material, wherein the focus zone is such that it includes at least one intensity maximum, which is transverse flattened in a flattening direction, or a transverse and/or axial sequence of asymmetric intensity maxima, which are flattened in a sequence direction. After positioning the focus zone in the material, a modification is created and the material and the focus zone are moved relative to each other in the or across to the flattening direction or in the or across to the sequence direction for forming a crack along an induced preferred direction.

An optically-transparent device (100) is disclosed which comprises a main part (10) of dielectric material having a refractive index n.sub.2, said device being configured for forming a field intensity distribution in a near zone of said device from electromagnetic waves incidentally illuminating said device, when said device is embedded into a dielectric material having a refractive index n.sub.1 lower than said refractive index n.sub.2. Said device (100) further comprises at least one insert (11) of dielectric material having a refractive index n.sub.3 higher than said refractive index n.sub.2, said at least one insert being at least partly inserted into said main part, said refractive index n.sub.1 being different from said refractive index n.sub.3, and wherein Formula (I) with W.sub.2 being a half width of said insert and Formula (II), Formula (III) with W.sub.1 being a half width of said main part and Formula (IV), with λ being the wavelength of the electromagnetic wave propagating in the dielectric material having refractive index n.sub.1.