Abstract: An apparatus comprising a first substrate comprising a nanostructured surface, thereby forming an optical metasurface; a mirror formed on a second substrate; and a mechanism arranged to move the first and second substrates relative to one another. The mechanism alters a separation between the first and second substrates between a first separation distance and at least a second separation distance. At the first separation distance the optical metasurface performs a first manipulation of incident light and at the second separation distance the optical metasurface does not perform the first manipulation of incident light. An optical system and a method are also described.

Abstract: A field detector (2) comprises a field-responsive element (10) which undergoes a dimensional change when exposed to a predetermined field; and an interferometric read-out arrangement arranged to detect the dimensional change of the field-responsive element. A light source (4) is arranged to provide a measurement beam reflected from the field-responsive element (10) and a reference beam not reflected from the field-responsive element (10), an optical detector (6) being disposed so as to detect at least part of an interference pattern produced by the measurement beam and the reference beam. The field-responsive element (10) has a shape comprising a curved surface and is constrained at least one edge (12) thereof such that the dimensional change causes the curved surface to be displaced in a direction which changes an optical path length of the measurement beam relative to the reference beam, thereby changing the interference pattern detected by said optical detector.

Abstract: A field detector (2) comprises a field-responsive element (10) which undergoes a dimensional change when exposed to a predetermined field; and an interferometric read-out arrangement arranged to detect the dimensional change of the field-responsive element. A light source (4) is arranged to provide a measurement beam reflected from the field-responsive element (10) and a reference beam not reflected from the field-responsive element (10), an optical detector (6) being disposed so as to detect at least part of an interference pattern produced by the measurement beam and the reference beam. The field-responsive element (10) has a shape comprising a curved surface and is constrained at least one edge (12) thereof such that the dimensional change causes the curved surface to be displaced in a direction which changes an optical path length of the measurement beam relative to the reference beam, thereby changing the interference pattern detected by said optical detector.

Abstract: This invention relates to a source for emitting radiation in the infrared range comprising a thin membrane including a radiation element made from a semi-conductive material having a chosen dopant, the radiation element being connected to a frame, the frame comprising connector means for connecting to a power source for conducting an electrical current through the substrate, the radiation element being provided with a periodic modulation of the refractive index constituting a photonic crystal having a chosen period, thus defining an optical resonator at one or more chosen wavelengths, and wherein the membrane is mounted to the substrate through a number of conductor beams distributed along the membrane circumference so as to provide an even current distribution and thus even heating over the membrane.

Abstract: This invention relates to a source for emitting radiation in the infrared range comprising a thin membrane including a radiation element made from a semi-conductive material having a chosen dopant, the radiation element being connected to a frame, the frame comprising connector means for connecting to a power source for conducting an electrical current through the substrate, the radiation element being provided with a periodic modulation of the refractive index constituting a photonic crystal having a chosen period, thus defining an optical resonator at one or more chosen wavelengths, and wherein the membrane is mounted to the substrate through a number of conductor beams distributed along the membrane circumference so as to provide an even current distribution and thus even heating over the membrane.