Optical density wedge

Described in this paper are three aspects of our work dealing with the verification of the performance of the system that may aid other users of the OMA 1) the measurement of the deterioration of the image caused by pulsing the SIT vidicon and how to eliminate the deterioration, 2) the measurement of pincushion distortion, and 3) the use of a triangular mask in a spinning rotor to simulate an optical density wedge. 

Densitometer. 0.0 -1.0 optical density wedge with 620 nm filter. 

In both cases, the distance from the light source to the sample plane was 10 cm. The light intensity was modulated using a 30 step transparent wedge of 0.1 optical density increments. Before each exposure, the sample and the mask were thermally equilibrated for 5 min at a designated temperature. 

The plates used were sli tly wedge-shaped in order to make the different reflection images more easily separable. The unevermesses on the optical flat surfaces were smaller than 400 A which is probably the limit obtainable. The area of the plates mainly used was 4 cm, their density at 15 C was = 2 556, their refractive index = 1 5209. Later on glass plates with area 1 cm, d 2 55, = 1 515 and quartz plates d s = 2 66 na (ord.)... 

Optical reflection color density was measured using a Macbeth model 914 filter densitometer. For simplicity, step-wedge numbers were used to represent logarithmic increments on the intensity axis. Phase diagrams were constructed by plotting the step number corresponding to a transition on the sensitometric curve against the exposure temperature. 

Fig. 9.96 (a) Mach-Zehnder interferometer with variable phase delay (p realized by an optical wedge, (b) Detected mean intensity (I) measured at / = 0, and phase-independent photon noise power density, measured at / = 10 MHz with and without input intensity Iq... 

Figure 6.5 Experimental setup for polarization dependent 2DPE. CCD = spectrograph and CCD camera, Ch = chopper, DO = diflractive optic, G = glass window, L = lens, M=mask, ND=neutral density filter, PM = parabolic mirror, S = sample, W=wedge pairs, WP=half-wave plate. Blue lines originate from the pump beam, green lines originate from the probe beam. Dotted red line is the evolved signal, which overlaps with the LO beam.

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