Isuke Hirano

Near-infrared time-resolved spectroscopy system for tissue oxygenation monitor

We have developed a three-wavelength (759,797, and 833 nm) time-resolved spectroscopy (TRS) system as a tissue oxygenation monitor employing a time-correlated single photon counting method. This system achieved a high data acquisition rate and system miniaturization maintaining a high sensitivity and time resolution. Our system succeeded in accurately measuring concentrations of oxy-(HbO2) and deoxyhemoglobin (Hb) by means of TRS data observation through studies using a phantom model and living tissue.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Theoretical study on absorption efficiency for a LD side-pumped Nd:YAG laser with the infinite convergence approach

We present a new technique to analyze the absorption efficiency of the active medium for a LD side-pumped Nd:YAG laser. A detailed ray trace has been carried out to evaluate the route of the pump LD-rays propagating inside the diffusing chamber. The method, named the infinite convergence approach, is used to determine the total absorbed power of a Nd:YAG rod when random reflection takes place at the inner surface of the reflector wall. By reason of losses caused by slits milled the reflector wall, there is an optimum slit width corresponding to the maximum absorption efficiency. It has been theoretically determined that the absorption efficiency can be summarized by a convergent result for the infinite energy transfer process inside the diffusing chamber. The method is applicable to the cavity design for any LD side-pumped solid-state lasers.

Potential switching of optical properties in polymer electrolytes

The electric field dependence of the optical properties of series of anion-conducting polymer electrolytes at an ITO-electrolyte interface was investigated. A change in reflectance and refractive index of polymer electrolytes [ poly( ethyl methacrylate)] 18 (Bu;jSnX) 3 Bu 4 NX where X = Cl, Br, and SCN was observed. This was ascribed to anion accumulation/depletion in the interfacial region. Shorter response times were observed for electrolytes with higher conductivities, illustrating the interrelationship between these two phenomena.