Adaptive photodichroic matched spatial filter

Holographic recording and reconstruction of polarized light with dyed plastic

Recording and reconstruction of the polarization state of the object beam is achieved by using dyed red plastic as a holographic material. Holographic characteristics are presented of dyed red plastic involving beam powers ranging between 3 and 120 mW/cm2 and exposure times in the order of minutes. It is also shown that the resulting modulation becomes photostationary under continuous exposure.

Real-time recording medium: photodichroic KF:LiF

Laser recording and readout measurements using the photodichroic crystal KF:LiF indicate that the material has potential as an input transducer and an adaptive spatial filter in an optical spectrum analyzer. These crystals are among the most photosensitive recording materials without gain, can be produced in large sizes at relatively low cost, and can be operated close to room temperature using thermoelectric coolers. Experiments using a high precision laser scanner providing 96.6-MHz subnsec pulses at 514 nm show that adequate recording can be accomplished with exposures less than 10 mJ/cm(2). An MTF of 40% at 72 1/mm was measured with uniform readout illumination of the recorded signal, but this is reduced if the signal is recovered by rescanning due to the convolution of the scanning beam profile with the recorded spot profile. The readout is destructive at the recording wavelength but can be read out with a much reduced decay rate by using 488 nm. The linear dynamic range in the Fourier plane was measured to be 40 dB.