Jahresbericht 2005 - IPHT Jena

64
a)
b)
Fig. 3.1: a) View of the compact UV-Raman
spectral sensor (circled) with a commercial
Raman spectrometer HR 600 with nearly the
same performance and b) measured spectra of
bacillus pumius, DSM 361, excitation wavelength
257 nm, with both instruments.
MIKROSYSTEME / MICROSYSTEMS
Unconventional micro-imaging
(R. Riesenberg, A. Grjasnow, M. Kanka,
J. Bergmann)
The coherent illumination of a sample by a pinhole
generates an interference image (inlineholography).
Results are given by unconventional
microscopic imaging by illumination with a pinhole
array, see Fig. 3.2. The microscopy by multiplane
interference detection uses three or more
interference pictures to reconstruct the objects.
The actual technique is adapted to microscopic
imaging. No reference is needed and a sub-pixel
algorithm is implemented.
The lensless technique is applied for wide field
imaging. The illumination by a pinhole-array
leads to a homogenous illumination with more
intensity and so with an increased sensitivity. The
field of view can be extended without loosing resolution
(see Fig. 3.3).
Fig. 3.2.: Arrangement of illumination of the
sample by a pinhole-array and interference
detection by a CCD.
Fig. 3.3: a…d above: Digital inline holography. Objects (diameter of 0.5 µm) at the edge of the illumination
cone (object plane in 10 µm distance from the pinhole-plane) can not be detected and reconstructed. For
a pinhole diameter of 1 µm the aperture is limited. The field of view is limited [hologram at a distance of
220 µm from the pinhole-plane, image area (200 µm) 2 , the field of view in the example is limited to about
(9 µm) 2 .
e…h below: The single pinhole is replaced by a pinhole-array (9 pinholes). Nearly all objects can be illuminated
and reconstructed. The field of view is extended.