The scientific name of ZAMIA Q series CO2 laser is all-metal seal-off RF-excited diffusion cooling slab-waveguidelaser,generally referred to as RF slab waveguide CO2 laser.
Different from the all-waveguide CO2 laser, the discharge area of the slab waveguide CO2 laser is composed of two rectangular metalslabsplaced in parallel and spaced apart by millimeters. Two optics are mounted at both ends of the two metalslabsto form a laser resonator for generating laser.
The cavity mirror has curvature, the curvature radiusoffront cavity mirrorisshorter, and the one of rear cavity mirror is longer, so the front cavity mirror is shorter than the rear cavity mirrorin length.The two cavity mirrors aremounted in alignment on one side, and the laser beam is output from the other side of the front cavity mirror.As shown below:
The space between the two electrode plates is several hundred millimeters long, several tens of millimeters wide, and several millimeters high. It can be seen from the numerical valuethat the size ofits heightdirectionis similar to that of the laser beam, much smaller than that of its widthdirection, so its shape is just like a flat sheet.In this space, discharge occurs andgain mediumis generated, andthe laser oscillating between the two resonators passes back and forth through thisspacemany times.
Each time the laser beam passes through this space,it showsdifferent transmission laws in the height and width directions: the size in the width direction is much larger than the size of the laser beam, so the laser beam passes freely in this direction without restriction; the size of the height direction issimilar tothe size of the laser beam, so the laser beam is constrained to passthroughin this direction each time.Becausethe laser beamsoscillate in the cavity for many times, passthrough the flat space between the two plates for many times,and is output on one side of the front mirror,the final output laser beams areasymmetric in the width and height directions.
In addition, the divergence angle and spot size of the laser beam in the two directions are different:the divergence angleis small inthe width directionand large in theheight direction, which means thatthe beam quality in the two directions is different.The schematic diagram of laser beam transmitted in free space after output from the resonator is as follows:
The above figure shows that the laser beam will change the shape of the spot with the different transmission distance,showingan elliptical spot in the far field. This laser beam is directly focusedand presentsan elliptical spot at the focus position.If the focus pointshowsan ellipticallaserspot,the thickness of the lines in the two directions will be inconsistent during processing, and the cutting effect will be different,thus finallyaffect the processing effect.
To obtain laser beams with the same divergence angle and the same spot size in two directions,it is necessary to shapeabove-mentioned asymmetric laser beams to obtain the same beam quality factors in the two directions, so that the circular symmetrical Gaussian beams of quasi-fundamental modecan be obtained.The circular focused spotcan be gainedby laser processing equipment such as marking machine and cuttingmachines.
To shape the laser beam into a complex system composed of a series oflens,asymmetric optical elements, such as cylindrical lenses or cylindrical mirrors, are generally introduced in two directions.
