Publications by authors named "M Kaivola"

Light sheets are optical beam-like fields with one-dimensional intensity localization. Ideally, the field intensity should be independent of the longitudinal and one of the transverse coordinates, which is difficult to achieve even for truncated light sheets. In this work, we present a general theoretical framework for intensity-interferometric continuous wave (cw) light sheets formed by overlapping the interference fringe patterns of mutually uncorrelated frequency components of the field.

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We demonstrate all-optical modulation and ultrafast detection using an on-resonance optical gain medium, combined with spectral splitting in a Fourier transform pulse shaper. Multiple spectral channels of one optical beam can be independently modulated in time by another beam, allowing high-rate modulation and multiplexing without requiring ultrafast response from the gain medium. For detection of sub-picosecond signals we demonstrate a method of ultrafast signal detection (temporal imaging with no spatial resolution) that utilizes the spatio-temporal tilt of an optical pulse in a pulse shaper.

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Some imaging techniques reduce the effect of optical aberrations either by detecting and actively compensating for them or by utilizing interferometry. A microscope based on a Mach-Zehnder interferometer has been recently introduced to allow obtaining sharp images of light-transmitting objects in the presence of strong aberrations. However, the method is not capable of imaging microstructures on opaque substrates.

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Article Synopsis
  • The metamaterial structure consists of parallel metal nanostripes that can act as a tunable partial polarizer for light.
  • The transmittance for TE-polarized waves is highly sensitive to the angle of incidence, dropping significantly with small angle changes, while TM-polarized waves remain relatively unaffected.
  • A second layer of a similar structure improves the tuning process, allowing for a smoother transition in transmittance from TE waves as the incidence angle increases.
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Wave retarders, including quarter- and half-wave plates, are used in many optical systems for polarization conversion. They are usually realized with anisotropic crystalline materials. However, much thinner and possibly also less expensive wave plates can be made of micro- and nanostructures.

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