The deposition of amorphous hydrogenated hard carbon (a–C:H) thin films from benzene vapor in a rf plasma is described. a–C:H was deposited on glass, quartz, Si, Ge, and GaAs. Negative self-bias VB and gas pressure P are shown to be the two significant parameters for an accurate control of the deposition process. The dependence of growth rate and deposition temperature on VB and P was determined; this gives an empirical relation for the average energy Ē of the ions forming the thin films. Refractive index (1.85–2.20 in the IR), optical gap (0.8–1.8 eV) and density (1.5–1.8 g/cm3) of a–C:H was measured. The optical gap varies linearly with the content of bonded hydrogen in the films. The density of a–C:H is proportional to the average ion energy Ē. We demonstrate the application of a–C:H as antireflective coating on Ge for 10.6 μm (reflection <0.2% at 10.6 μm) and as terminating layer of an optical multilayer stack.

Infrared pulses were generated over the range from 1.2 to 10 μm in a single path system consisting of two AgGaS2 crystals. A high photon conversion efficiency between 10−1 and 10−3 was found depending upon the emission frequency. A bandwidth of approximately 10 cm−1 for idler pulses between 6 and 10 μm was observed. With a Nd:yttrium aluminum garnet laser pump of 20-ps pulse duration one observes parametric pulses of 8 ps.

Some of the unique reconstruction properties of image plane holography are derived from the well-known imaging equations of holography. These properties are illustrated experimentally with focused holograms using both external and locally generated reference beams. The relative advantages of lenses and hologram optical elements are presented with particular reference to local reference beam focused holography and some of the photographic film parameters which are important for optimum image reconstruction are presented. Image plane holography offers a practical technique for producing inexpensive,bright, white light displays.

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