BOXCARS experimental arrangement

Figure 1. Schematic of BOXCARS experimental arrangement BS, beamsplitter L, lens D, dichroic OF, optical flat P, prism F, filter DC, dye cell T, trap TM, partially transmitting mirror (24).

In some experimental arrangements, boxcar integrators are used instead of digital oscilloscopes. The basic operational scheme of a boxcar integrator is shown in Figure 3.26. 

Figure 12. Experimental diagram from Ref. 9 demonstrating the experimental arrangement used to generate BOXCARS spectra. For legend symbols see Figure 2.

To measure the t/coefficients of a poled polymer sample, the Maker fringe SHG experiment [40] is frequently carried out. The experimental arrangement is shown in Fig. 26.4. A polarized laser beam from a Q-switched Nd YAG laser (A = 1.064 /u,m) or other IR laser source is employed. The fundamental laser beam at a frequency 0) passes through the poled polymer sample and an appropriate IR blocking filter. The SHG signal is selected with an interference filter at the corresponding frequency 2o), detected by a photomultiplier tube, and measured with a boxcar integrator. The SHG intensity, /(2w), can be expressed as... 

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