K. Nanri

High-efficiency operation of chemical oxygen-iodine laser using nitrogen as buffer gas

High-efficiency operation of supersonic chemical oxygen-iodine laser (COIL) with an advanced jet-type singlet oxygen generator using nitrogen as buffer gas was demonstrated. Laser output was remarkably increased when buffer gas was cooled with liquid nitrogen. The effects of buffer gas temperature on the characteristics of the oxygen-iodine laser medium was discussed. A net chemical efficiency of 23.4% was obtained at 405 W when the chlorine molar flow rate was 19 mmol/s.

Trace NO/sub 2/ detection with Yb fiber laser pumped mid-IR difference frequency generation

A novel high power Yb fiber laser pumped cw narrow-linewidth tunable mid-IR coherent source based on a difference frequency generation (DFG) in a periodically poled LiNbO/sub 3/ (PPLN) crystal for trace gas detection was demonstrated.

Ion cyclotron resonance in a magnetized sheet plasma

Separation of ionic or isotopic species in a magnetized sheet plasma has been studied by using the ion cyclotron resonance method. The sheet plasma was used instead of a cylindrical plasma in which many unfavorable collisions take place. An rf electric field is applied to the plasma by two parallel plate electrodes. It is shown that a resonance is strongly dependent on the plasma space potential across the sheet plasma. The resonance spectra of argon, neon, and nitrogen ions in the low dense sheet plasma with a shallow potential well are clearly observed, while the resonances in high dense plasma with a deep potential well are not observed. It is also found that the resonance frequency for a corresponding ion is proportional to the magnetic field strength.

Isotope separation in a magnetized sheet plasma by ion cyclotron resonance

Abstract The isotope separation experiment in a sheet plasma has been studied by using ion cyclotron resonance heating. The sheet plasma flowed into two parallel plate electrodes to which an rf electric field with a frequency equal to an ion cyclotron for the desired isotopic species was applied. The observed resonance frequency is 180 kHz, however, the ion cyclotron frequency of Ar ion is 65 kHz. This discrepancy may be explained in terms of plasma space potential in the sheet plasma. The ion saturation current in a Langmuir probe gives a maximum value of 6.7 V/cm and 2.3 kG.

An experimental study on a cylindrical multi-pass cell

A new type multi-pass cell was demonstrated for absorption spectroscopy. This cell is useful when performing gas measurement. Moreover, the optical characteristic of a cell was verified.

Instantaneous measurement of NH/sub 3/ and NO/sub x/ by using near- and mid-infrared coherent light sources

Instantaneous measurement of NH/sub 3/ and NO/sub x/ both in near-infrared (near-IR) and mid-infrared (mid-IR) region provided by single difference frequency generation device is demonstrated.

Two-dimensional oxygen-distribution imaging in a laser cut kerf on two-tracer LIF technique

Two-tracer Laser Induced Fluorescence (LIF) technique with toluene and 3-pentanone is applied to visualize the assist gas flow in the laser cut kref. Assist gas distribution and oxygen concentration in the quartz model kerf is visualized.

An intelligent gas detector based on Raman scattering spectroscopy pumped by power build-up cavity

Intelligent gas detection to monitor Hydrogen concentration based on stokes Raman scattering was demonstrated. Power Build-up Cavity (PBC) as a light source, Avalanche Photo Diode (APD) was employed. The detection limit was lower than 200ppm.

Dual gas (NH 3 and NO 2 ) laser absorption measurement by tailored signal and idler wavelength in difference frequency mixing process

Absorption measurements of NH3in 1.53 μm wavelength region and NOx in 3.46 μm wavelength region are performed at the same instant by using single optical gas sensing system based on difference frequency generation (DFG).

An ultra-compact NO2 detector based on cavity ringdown spectroscopy using a laser diode pumped power build-up cavity

A novel gas detector to monitor nitrogen dioxide (NO2) concentration based on continuous-wave cavity ringdown spectroscopy was demonstrated. A sensitivity of 2 × 10^-7cm^-1was achieved using a compact laser diode power build-up cavity.