We report experimental observations of field-induced transparency in a solid medium. Absorption reduction of 20% was observed in ruby using a magnetic field for the creation of closely spaced lower levels and a microwave field for the coupling of these states. [S0031-9007(97)

The tendency to sneeze upon exposure to bright light is autosomal dominant and affects 18-35% of the population. This uncontrolled sneezing may represent a danger to pilots during flight. Testing was conducted using Ditric narrow band (+/- 10 nm) interference filters. Wavelengths at 430, 532, and 560 nm were tested with a GE 500-W photoflood BCA #1 bulb at constant intensity. Subsequent testing of military and civilian aviation goggles and sunglasses was conducted using a Digikrom 240 monochromator. Repeated testing with interference filters in a clinical setting showed no effect on sneezing in a susceptible subject. The photic sneeze reflex does not appear to be mediated by specific wavelengths of light, but rather by the change in light intensity. This could trigger an unexpected sneezing episode during critical periods of flight. This is an unrecognized and previously unreported danger to fixed-wing and rotary aircraft pilots.

No abstract

We demonstrate mixed binary multiplication of two or three numbers represented as spatial bit patterns by using a backward stimulated photon echo in a low-temperature solid activated by rare-earth ions. The photon-echo output image is the convolution-correlation of input images in a holographic arrangement, which can be interpreted as multiplication in a mixed binary format. The computation is extremely fast (~ 50 ns) and may be combined with temporal data processing for a versatile vector and matrix processor.

The observation of phase conjugation in InGaAs/GaAs multiple quantum wells at 1.06 μm wavelength is reported on. The effective nonlinearity of the sample used in our experiments was measured to be χ(3)=10−7 esu. The nonlinearity is induced by the saturation absorption due to band filling and exciton bleaching. The saturation intensity is 1.3 kW/cm2.