In a number of procedures of spectroscopic measurements, the time-resolved spectrophotometry has become of increasing importance during the past several years as a tool for examining high temperature plasma, laser, chemical reaction, etc. The technique of high speed spectrophotometry has been advanced in parallel with the progress of radiation detectors and information processing technology. A wide variety of the techniques for presenting the time-resolved spectra including conventional photographic, rapid scanning and stroboscopic methods are classified and illustratively reviewed with particular emphasis placed on current status.
A bolometer, using carbon slab cut from the core of a carbon resistor as a temperature-sensitive resistive element, has been constructed and operated at 1.68°K with a responsivity of 1.9×104 V/W, a noise equivalent power of 7.8×10-11W and a time constant of several milliseconds. Theoretical responsivity calculated from thermal equation is in good agreement with experi-mental results. The performance is much affected by thermal conductance and temperature co-efficient of electrical resistance and a temperature of a thermal bath. This bolometer is suitable for transmission measurements at liquid helium temperature.
An experiment to construct holograms using sound wave (20 Kc) and to reconstruct the original images using laser light (6328Å) is conducted. The acoustic fields are detected by a microphone which scans the fields mechanically. The electric signals from the microphone are amplified and they lighten a lamp fixed on the back of the microphone. The light intensity distributions con-verted from the acoustic field distributions are recorded on films by a camera as sound wave holograms. The original images are reconstructed to illuminate the obtained sound wave holograms of reduced size by laser light.
A new light communication system is proposed, which makes possible to do mutual communi-cation between two separate stations using only one laser transmitter. Light from a gas laser set in a station A is modulated by a modulator K2 and propagated to the other station B. A part of the modulated light is demodulated by the detector in the station B. A new signal is superposed by the modulator K2 in the station B on the rest of the modulated light which is folded back to the station A. The azimuthes of the optical components are selected so as to eliminate the mutual interference of the two modulated signals transmitted through the going and the coming back path. The optimum conditions obtained by use of Jones matrices were examined by telephone call experiments using ADP pockels modulators.
The power spectrum of the speckle pattern of the light from an extended diffused source is known to be proportional to the autocorrelation function of the source illumination function. Through use of this property, an attempt was made to obtain the correlation functions of two-dimensional patterns, taking the pattern to be processed as the source illumination function. The power spectrum may be obtained by a diffraction technique from a photo-graphic film on which the speckle pattern is recorded.