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Ken'ichi Nakagawa

Publications and source records attributed to Ken'ichi Nakagawa.

3 recordsLinked to original sources

Laser-design methodology for extending an available wavelength range of dual-wavelength injection-seeded laser

This paper describes a method for expanding the applicable wavelength range of dual-wavelength oscillation injection-locked lasers. Special focus is placed on the laser design that enables simultaneous oscillations at both the gain center and gain tail, requiring the most stringent requirements. We show that a sufficient performance can be achieved by introducing a wavelength-dependence property onto the output coupling mirror, without giving any losses in the laser resonator. We also show how we can determine such wavelength-dependent property on the basis of experimental measurements. Using the designed output-coupler, in practices, we demonstrate simultaneous oscillations with an equal output power, across a variety of wavelength combinations of near the gain center and around the gain tail in which the wavelength separation amounts 60 nm at the most.

physics.optics↗

Generation of five phase-locked harmonics by implementing a divide-by-three optical frequency divider

We report the generation of five phase-locked harmonics, f_1: 2403 nm, f_2: 1201 nm, f_3: 801 nm, f_4: 600 nm, and f_5: 480 nm with an exact frequency ratio of 1 : 2 : 3 : 4 : 5 by implementing a divide-by-three optical-frequency divider in the high harmonic generation process. All five harmonics are generated coaxially with high phase coherence in time and space, which are applicable for various practical uses.

physics.optics↗

Rectified momentum transport for a kicked Bose-Einstein Condensate

We report the experimental observation of rectified momentum transport for a Bose-Einstein Condensate kicked at the Talbot time (quantum resonance) by an optical standing wave. Atoms are initially prepared in a superposition of the 0 and -2*hbar*kl momentum states using an optical pi/2 pulse. By changing the relative phase of the superposed states, a momentum current in either direction along the standing wave may be produced. We offer an interpretation based on matter wave interference, showing that the observed effect is uniquely quantum.

quant-ph↗