Wire-grid polarizers (WGPs) are currently limited by their wafer-scale manufacturing methods to sizes of approximately 12 to 18 in. For large-size displays, a new method for the production of large-area WGPs is required. Large-area WGPs were simulated using the finite-difference-time-domain method, and a scaleable method for their production based on a block copolymer (BCP)-nanostructured template was implemented. The nanostructured template is globally aligned through the use of a cylinder-forming liquid crystal (LC) diblock copolymer, which is first aligned on a rubbed polyimide substrate. A surface-relief template is produced using the differential dry etch rates of the cylinder-forming component and LC polymer matrix component of the BCP. The template is metalized to produce a WGP. Polarizers of arbitrary size with polarization efficiency up to 0.6 have been made in close agreement with calculated values for idealized structures. The choice of the cylinder-forming polymer is critical to the degree of alignment of the template, and the thermal stability of the LC polymer matrix is critical to the stability of the template during etching.
In digital holographic microscopy, a hologram of an object is recorded by an electronic image sensors and a computer is used to reconstruct the original object numerically. A number ro different arrangements have been successfully used, for example by Haddad, Schnars, Takaki and Jacquot. There is an intermediate case between the Fourier-transform method of Haddad et al and the Fresnel arrangement used by Jacquot et al, which has some of the advantages of both methods. A point reference source in a lane some distance from object provides the spatial frequency reduction in the hologram plane, as for Fourier transform methods, without the strong central peak and with the twin image defocused in the object plane. This arrangement is tested, showing that it can produce a resolution significantly improved over the Fresnel case. We also consider the removal of the holographic twin image in the Fresnel in-line holographic arrangement. The high-contrast parts of the image are assumed to be part of the true image, and the twin image corresponding to these high-contrast elements is subtracted, leaving an improved estimate of the true image only. We present experimental results demonstrating this method for a number of different objects.
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