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Description:
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In this thesis , a 6 -beam combiner using multiplexed holograms in dye -doped polymer is investigated . It is realized by recording six superimposed holographic gratings , which show uniform diffraction efficiency . The coupled wave theory for N superimposed gratings is more generalized and is used to analyze the amplitudes of diffracted waves in three different boundary conditions .
Multiple -ring diffracted beam analysis is proposed to determine the dynamic range of a holographic material . The M / # is evaluated by recording a single hologram and counting the number of ring patterns in the diffracted beam . This analysis is extended to assess the equalized grating strength of N superimposed holograms . Six holograms with the equalized grating strength which can be assigned within the dynamic range of our material and show maximum diffraction efficiency are recorded .
The phase locking of five beams to one reference beam is performed using PZT controller . The designs of lock -in amplifier , ramp generator and servo using commercial chips are demonstrated . The readout set -up used to split one single beam into six coherent copies is presented . The function of each part of the PZT controller in the readout set -up is discussed in detail .
The intensity profile of an N -beam combiner is investigated by varying the phase angle between adjacent input waves . The entire solution which describes the amplitude of a combined beam is derived from generalized coupled wave theory . A simplified experimental set -up without a complicated PZT controller is demonstrated using a planoconvex lens . In order to provide six coherent light sources in future work , the injection locking of a single laser diode to the master laser diode is performed . An expected read -out setup is proposed to carry out both the achievement of six coherent sources and a 6 beam combination . |