The aim of this project is to develop new technique that allows single electron manipulation by the light. The novelty of the project is to take advantage of the unique capabilities of carbon nanotubes for single electron detection to study electronic properties of various types of molecular systems subjected to external light source. To do this a novel nanodevice layout consisting of the carbon nanotube (CNT) combined with quantum dots or molecules is proposed. In the device layout the CNT is acting as a ultra-sensitive detector for single electron detection and the quantum dot is attached to only one electrode – a nanotube. Two configurations of the device layout are proposed. In the first scenario the nanotube and the probed molecule are laying on an insulating oxide surface and in second scenario the device is suspended. This layout overcomes problem seen in standard devices where a molecular system is placed between two electrodes and very often it turns out that it is impossible to pass any measurable current through the system.Detection scheme is based on the fact that electrons can tunnel between the quantum dot and the tube detector. Electron transport between these nanoobjects will be controlled by light illumination and it will be detected by means of electron counting spectroscopy technique. The proposed idea represents a new strategy to study the separation in energy between the electronic discrete levels of the quantum systems subjected to the light illumination.Another aim of the project would be to investigate the effect of light on the transport properties of molecules that can undergo structural and electronic modification upon light exposure. Upon light exposure some molecules can undergo a process that results in change of the shape of the molecule. This will modify the molecule-tube tunnel barrier in the device. Light can also change the separation between energy levels of the molecule. Both cases can be monitored by proposed technique.