THIN-FILM WAVE-GUIDE SENSOR FOR MEASUREMENT OF THE ABSORPTION-COEFFICIENT OF HEMOGLOBIN DERIVATIVES

A simple method for determining the absorption coefficient of oxyhemog lobin and deoxyhemoglobin in human blood is proposed. The method is ba sed on a variation of the complex propagation constant of guided wave in a thin-film optical waveguide. On the waveguide layer, a serial mul ti-channel sample chamber is constructed to vary the interaction lengt h between the evanescent field and the sample, and the dependence of t he sensor response on the interaction length is investigated for Vario us concentrations of two hemoglobins. The response of this sensor is l inearly proportional to the interaction length and the concentration o f the two hemoglobins. The attenuation constant due to the evanescent field absorption between the channels is experimentally obtained with the designed sensor, and the absorption coefficient is determined by t he proposed method. The determined absorption coefficients coincided w ith those obtained by conventional transmission measurement.