The value of absorption of light energy is dependent on the number of molecules present in absorbing material and the thickness of the medium. Thus, intensity of light energy leaving the absorbing substance is used as an indication of concentration of that particular substance. If the thickness i.e. path length of the light energy in the sample holder, normally the flow through cell and intensi...

In the current work, the effect of surface morphology on light emission property and absorption behavior of quasi-columnar macro-porous silicon (PS) was investigated. PS structures with different morphology were synthesized using photo-electrochemical etching method by applying different etching current densities. SEM micrographs showed that empty macro-pores size and porosity of PS layers were...

static properties, relatively intensity noise and intensity modulation response in quantum cascade lasers (qcls) studied theoretically in this paper. the present rate equations model consists of three equations for the electrons density in the conduction band and one equation for photons density in cavity length. two equations were derived to calculate the noise and modulation response. calcula...

An efficient technique for calibrating video cameras to record optical density (OD) from microscopic images is described. The method corrects for variation over the field of the brightfield and darkfield intensities, does not assume a linear response of the camera to the incident intensity and requires a single calibration filter.