Researchers at the University of Illinois have developed a method of applying optical parametric amplification technology to enhance ultrweak signals from scattering biological tissue. This method can also be utilized for other types of signals such as fluorescence, parametirc processes, and Raman for tissue analysis in research applications. Although high sensitivity photodetectors exist, this method deals with instances of extremely low-level light signals that w ould otherwise result in long integration time and slow imaging speed. This method solves issues that ussually occur with the current application, i.e. low spatial and temporal coherence and the incompatibility of high intensity/low repition rate lasers with biological samples.