Naoto Uehara

Learn More
We describe the accurate measurement of the radius of curvature of a concave mirror in a Fabry-Perot interferometer with a finesse of 78,100. The radius of curvature of the concave mirror is determined by measuring the free spectral range and the transverse-mode range with the frequency response functions. The radii of curvature at two orthogonal (x and y)(More)
We describe an ultralow-loss and high-reflectance mirror at 1064 nm. A Fabry-Perot cavity is fabricated with two mirrors to measure the finesse and the transmission efficiency on resonance. The finesse was cross checked by two different methods: measurements of the cavity decay time and of the frequency-response function. As a result, a loss of 6 +/- 6 x(More)
We report on the use of a fixed-spacer Fabry-Perot ring cavity to filter spatially and temporally a 10-W laser-diode-pumped Nd:YAG master-oscillator power amplifier. The spatial filtering leads to a 7.6-W TEM (00) beam with 0.1% higher-order transverse mode content. The temporal filtering reduces the relative power fluctuations at 10 MHz to 2.8x10(-9)/(More)
The stress distribution of tablets after compression was simulated using a finite element method, where the powder was defined by the Drucker-Prager cap model. The effect of tablet shape, identified by the surface curvature, on the residual stress distribution was investigated. In flat-faced tablets, weak positive shear stress remained from the top and(More)
BACKGROUND Granule characteristics are some of the important intermediate qualities that determine tablet properties. However, the relationships between granule and tablet characteristics are poorly understood. The aim of this study was to elucidate relationships among formulation factors, granule characteristics, and tablet properties using a non-linear(More)
We describe the ultrahigh-frequency stabilization of a diode-pumped Nd:YAG laser by use of a high-poweracceptance photodetector. The photodetector, which is constructed with an optical power divider and eight combined photodiodes, is developed to reduce shot-noise-limited FM noise. The laser frequency is locked to a Fabry-Perot cavity with a finesse of(More)
We describe frequency-stabilized laser-diode-pumped Nd:YAG ring lasers locked to a high-transmission and high-finesse reference Fabry-Perot cavity. The cavity has a resonant linewidth of 38.0 kHz, a finesse of 19,400, and a transmission efficiency of 79.4% for the TEM(00) mode. We measure the frequency stability by locking two lasers one free spectral range(More)
  • 1