In recent years, a great deal of emphasis has been placed on achieving the diffraction limit with large aperture telescopes. For a well matched focal-plane instrument, the diffraction limit provides the highest possible angular resolution and sensitivity per pixel. But it offers another key advantage as we now show. Conventionally, as the telescope aperture D grows, the instrument size grows in...

OF DOCTORAL DISSERTATION HELSINKI UNIVERSITY OF TECHNOLOGY P. O. BOX 1000, FI-02015 TKK http://www.tkk.fi Author Antti Säynätjoki Name of the dissertation Manuscript submitted 3.3.2008 Manuscript revised 5.5.2008 Date of the defence 23.5.2008 Article dissertation (summary + original articles) Monograph Faculty Department Field of research Opponent(s) Supervisor Instructor Abstract

High contrast grating (HCG) is a new class of optical grating with many distinct features that are not found in conventional gratings [1–6]. These features include broadband ultrahigh reflectivity, broadband ultrahigh transmission, or very high quality factor resonance, for optical beam surface-normal or in oblique incidence to the direction of grating periodicity. Furthermore, these features c...

By placing changeable nanofabricated structures (wires, dots, etc.) on an atom mirror one can design guiding and trapping potentials for atoms. These potentials are similar to the electrostatic potentials which trap and guide electrons in semiconductor quantum devices like quantum wires and quantum dots. This technique will allow the fabrication of nanoscale atom optical devices. PACS. 03.75.Be...

Magnetooptical garnets combine high Faraday rotation with low optical losses in the near infrared region where optical communication via glass fiber is established. In this spectral range garnets are the only materials discussed to realize nonreciprocal devices as optical isolators and circulators. Although such devices are available as microoptical components, practical versions of their integ...

Microfluidic systems have a large variety of applications in biomedicine and life sciences. One of the problems occurring in practical systems is the adhesion of cells and micro-particles to the walls of microfluidic channels and reservoirs. For scientific examinations, e.g. for drug testing, it is necessary to expose specific test cells to different media. The cells are moved between the reser...

A novel surface micro-machined micro-optical bench (MOB) has been demonstrated. Free-space micro-optics such as micro-Fresnel lenses, rotatable mirrors, beam-splitters and gratings are implemented on a single Si chip using IC-like microfabrication processes. Self-aligned hybrid integration with semiconductor lasers are also demonstrated for the first time. The MOB technology realizes a microopt...

Integrated optics (IO) is an optical technology that allows to reproduce optical circuits on a planar substrate. Since 1996, we have investigated the potentiality of IO in the framework of astronomical single mode interferometry. We review in this paper the principles of IO, the requirements for interferometry and the corresponding solutions offered by IO, the results of component characterizat...

Thin film integrated optics components such as light guides, modulators, directional couplers, and polarizers demand high quality edge smoothness and high resolution pattern formation in dimensions down to submicrometer size. Fabrication techniques combining holographic and scanning electron beam lithography with ion beam micromachining have produced planar phase gratings with intervals as smal...

We show the feasibility of controlling the magnetic permeability of optical semiconductor devices on InP-based photonic integration platforms. We have achieved the permeability control of GaInAsP/InP semiconductor waveguides by combining the waveguide with a metamaterial consisting of gate-controlled split ring resonators. The split-ring resonators interact magnetically with light travelling in...