Akira Takeshima

Temporal characteristics of picosecond continuum as revealed by a two-dimensional analysis of streak images

Abstract A two-dimensional analysis has been made for streak images of picosecond continua generated in D2O, CCl4, saturated aqueous solution of KDP, H3PO4 and quartz block. Their pulse width and distribution of arrival time at the streak camera were determined as a function of the wavelength.

A New Picosecond Synchroscan Photometer

A picosecond synchroscan photometer has been developed to obtain a picosecond temporal resolution and an improved dynamic range of more than 105 : 1, utilizing a newly developed synchroscan streak tube and a direct photomultiplier readout. Advantages include a potentially improved S/N ratio, a lower detection threshold and reduction in cost. A greatly improved high dynamic range of 2 x 105 : 1 with a temporal resolution of better than 47 ps has been demonstrated, by measuring picosecond pulses from a laser diode. The limiting time resolution of this system is estimated to be =10 ps. This technique and its limitations are discussed.

Streak-camera-based long-distance range finder with 10(-7) resolution.

A novel optical distance meter with a pulsed yttrium aluminum garnet laser and a pair of streak cameras is developed. To minimize timing errors, the time scale is marked by an optical-registration-clock pulse. This assures an intrinsic resolution of 3 mm. For field applications, comparison of multiwavelength and single-wavelength methods confirms that the latter method is much better if carefully corrected. By use of the equipotential temperature criterion for correction of the atmospheric parameters, such as the atmospheric boundary layer effect and the temperature along the ray trajectory, a resolution of better than 1 cm is achieved over a range of 30 km. This result corresponds to a relative resolution of 3 × 10(-7). Typical ranging results in a geophysical application are shown for monitoring of the relative translational shift of the Asian (Eurasian) and the Philippine plates; the predicted shift is found to be absent.