Prof. Mario C. Marconi

Department of Electrical and Computer Engineering, Colorado State University


Time resolved holographic imaging



Experimental set up

Text Box:    Figure 1: Scheme of the experimental set up.  The EUV laser beam is splitted by a zone plate and generates an illumination beam (zero order) and a reference spherical beam (1st order).  The interference between these two beams is recorded in a CCD.  A beam stopper (beam block) prevents the zero order from saturating the detector.












A Fourier Transform Holography (FTH) configuration was implemented using as illumination source a table top EUV capillary discharge laser. The holograms are recorded in a charged-coupled device (CCD) camera and numerically reconstructed.  With this experimental configuration it was possible to achieve time resolved holograms (or flash holograms) with a temporal resolution determined by the laser pulse width, in this case 1 nanosecond.   Figure 1 is a schematic of the experimental set up for holographic recording. The EUV laser radiation was directed onto the Fresnel zone plate which was used as a beam splitter, generating the illumination and the reference beams.  The object (a nanopillar array) was located in close proximity of the zone plate focal plane.  The un-diffracted zero order beam illuminated the object (nanopillar array) producing a diffracted object beam. The object beam was superposed in CCD detector plane with the spherical wave generated by the first order focal point of the zone plate.


Time-resolved imaging of oscillating pillars

Text Box:    Figure 2: Sequence of holograms displaying oscillating pillars.  The images with the pillars in different locations can be composed in a “movie” of the oscillating pillars that is available by request















Time-resolved holograms of oscillating nanopillars were recorded using single-shot exposure.  Each pillar has a length of 15 µm and a width of 200 nm. The sample was attached to a ceramic piezoelectric that was excited with a sinusoidal wave 10 V peak to peak at a frequency of 1.16 MHz.  Several single shot holograms were recorded of the oscillating pillars using the experimental set up shown in Figure 1. Figure 2 is a sequence of different single shot holograms obtained in different positions of the pillars. With this sequence of images it was possible to compose a “movie” of the oscillating pillars by sequentially displaying the different images as frames in a film.  The movement of the pillars is clearly visible in the movie.  To see the movie click HERE.