The invention relates to an apparatus and method for the detection of the spectral absorption properties of a fluid in a microenvironment, the apparatus comprising a radiation source, a microfluidic device and detection means, wherein the apparatus additionally comprises means for increasing the path length of the radiation through the fluid. The method includes: capturing a current image by an image capture device of the terminal; analyzing current ambient brightness according to the current image; and adjusting display of an interface on the terminal according to the current ambient brightness. The optical beamforming RF transmitter also includes an array of antennas, where each antenna has an optical input configured to drive the corresponding antenna, and an array of optical modulators, such that each modulator has an output connected to a corresponding one of the antennas and an input connected to one of the outputs of the optical WDM splitter.