One-dimensional Doppler laser collimation of chromium beam with a novel pre-collimating scheme

A novel pre-collimating scheme in laser-focused chromium(Cr)atomic deposition is presented.It consists of three apertures,which are one main pre-collimating aperture at centre and two probing apertures with uniform dimension at both sides of the central one.The calculations show that the Cr atomic beam is divided into three parts accordingly after going through this scheme,and the full-width at half-maximum (FWHM)of each part decreases while the peak value increases after one-dimensional(1D)Doppler laser collimation,subsequently.Compared with that before laser collimation,the central part does not have displacement,but each part of the other two has the same displacement to the centre after laser collimation. These phenomena which are agreed with experiment prove that the novel pre-collimating scheme is a feasible means to solve the problem which we cannot observe the collimation of Cr atomic beam after substrate in laser-focused deposition with a pre-collimating scheme of only one aperture,because the atoms will be obstructed completely by the substrate.