This paper reviews the state of the arts of ultra-short light pulse generation techniques and their applications. A variety of pulse generation techniques has been used to obtain sub-nanosecond pulses. Mode-locking is an especially important technique to obtain picosecond pulses, which is reviewed in detail with emphasis on recently developed mode-locking schemes for dye lasers and solid-state lasers. A survey is also made on light pulse generation with a semiconductor laser, which has unique characteristics. Emphasis is placed on the roles of active optical control techniques in ultra-short optical pulse generation. Various examples of applications are reviewed from the opto-electronical point of view.
Products Development Laboratory, Mitsubishi Electric Corporation, Electrophotographic properties of polyethylene terephthalate-CdS photoreceptors have been studied with the following conclusions. (1) In negative corona charging, the starting voltage of electrical discharge of the CdS layer, which becomes equal to the starting voltage Vthd' of dark areas at about 5500A, decreases with increasing wavelength of imaging light. (2) Although Vchd' increases with the thickness of the CdS layer in the thinner regions, it approaches a constant value of about 1600 volts in regions thicker than 100±10μm. It is confirmed that phenomena (1) and (2) can be explained by theoretical equations derived on the basis of the volume charge capacitor model. (3) By soaking silicone oil into the US layer added with the resion binder of about 5wt%, electrical dischage of air spaces can be removed completely without appreciable decrease in the photosensitivity to within 10%.
Based on a simple detector model, the spectral response of PbSnTe infrared detector is calculated, taking into account the non-parabolic nature of the band and the band filling effect. The spectral response easily changes with surface carrier concentration and junction depth. This feature is illustrated and can be utilized to make detectors with any desired spectral response.