TECHNOLOGY FOCUS - IMAGING AND COMMUNICATION - Preferred Process: The process also comprises varying the laser pulse regarding its shape until the molecules show a composition optimizes according to the predefined composition. The molecules have been extracted as a result of the absorption of energy quanta. The process also comprises varying the form of the laser pulse until further variations achieve no further approach to the predefined composition. The process during iterative process to shape a laser pulse includes irradiating laser pulse into gas to excite the molecules, extracting multi-excited molecules from gas, measuring the composition of the extracted multi-excited molecules, comparing the composition with predefined composition, and varying form of laser pulse and repeatedly directing the laser pulse into the gas until the composition of the extracted molecules is optimized according to the predefined composition. The method also comprises performing the iterative process and the variation of the form of the laser pulse in accordance with evolutionary algorithm. The process also comprises using a laser pulse detection unit to determine the temporarily and spectral form of the laser pulse.Preferred Components: The laser pulse is amplitude and/or phase modulated. The modulation of the laser pulse is charged by the iterative process. The molecules of the gas after the absorption of the first energy quantum form the laser pulse are brought into electronically excited quantum states energetically above the vibrational ground state in a way that the wave packets formed by the excited molecule-specific excitation spectra and require energy quanta of the different energy for further excitation. The molecules to be separated are selectively excited by the laser pulse several times in a way that the molecules can be extracted. The molecules to be separated are selectively excited by the laser pulse several times in a way that the molecules can be extracted, are excited into Rydberg-states and ionized by electromagnetic fields, or are ionized by multi-excitation. The multi-excited molecules to be separated are extracting chemically or by electromagnetic fields. A femto-second laser is used to generate the laser pulses. The separating device also comprises evaluation unit interacting with the control unit and evaluates the composition of the separated molecules of the different excitation-spectra as detected by the detector. The evaluation unit and detector unit include computer program controlling the iterative process. The pulse modulator comprises controllable liquid crystal mechanisms. The liquid crystal mechanism modulates the form of the laser pulses, particularly the phase and/or amplitude of the laser pulses. The control unit contact in the liquid crystal mechanism of the pulse modulator to vary the form of the laser phase. The iterative process follows an evolutionary algorithm. The device also comprises mass spectrometer, i.e. quadruple mass spectrometer measuring the composition of specific masses of the extracted molecules, ion detector (3) for measuring the ionized molecules, electrostatic extraction unit for merged ions for extracting multi-excited molecules, laser pulse detection unit for determining the temporary and spectral form of the laser pulse. The pulse modulator is arranged in the Fourier-plane of grid pattern for generating laser pulses shaped in time and frequency in order to form laser pulses. The variation mechanism varies the form of the laser pulses if the comparison by the comparative device shows that the measured composition is not optimized. The variation of the form of the laser pulses to the control mechanism. The iteration process follows an evolutionary algorithm.