1, end-pumped solid-state laser
The biggest advantage of end-pumped mode is that it is easy to obtain good beam quality and can realize high brightness solid-state laser. The efficiency of end pumping is higher. This is because, under the condition that the pump laser mode is not too bad, the pump light can be coupled into the working substance through the converging optical system, and the coupling loss is small; On the other hand, the pump light also has a certain mode, and the mode of the generated oscillating light is closely related to the pump light mode, so the matching effect is good, so the working medium has a high utilization rate of the pump light.
It is precisely because of the advantages of high efficiency, good mode matching and wavelength matching that end-pumped mode has developed rapidly in the world and become one of the key development directions of laser science. It is widely used in laser marking, laser micromachining, laser printing, laser display technology, laser medicine and scientific research, and has great market potential.
2. Side-pumped solid-state laser
The laser head of a side-pumped solid-state laser is a pump source composed of three diode pump modules in a circle, and each pump module is composed of three diode linear arrays with microlenses. The average output power of each linear array is 20W, and the output wavelength is 808nm. The device skillfully designs the pump cavity and refrigeration channel by using the glass tube. Most of the surface of the glass tube is coated with 808nm high reflection film, and the rest is coated with three layers of 808nm antireflection film at 120 to form a pump cavity. The light emitted by the semiconductor pump source is converged to three long and narrow areas coated with antireflection films through three pairs of beam shaping lenses, and then absorbed by the crystal through the glass tube wall. Because most areas of the glass tube are coated with highly reflective films, the pump light will be reflected back and forth in the pump cavity until it is completely absorbed by the crystal, forming a uniform gain distribution on the cross section of the crystal.
At the same time, the glass tube can also be used for refrigeration, and the cooling water passing at high speed can quickly take away the generated heat. The crystal is a Nd:YAG rod with composite structure, the effective size is j3*63mm, and the doping concentration is 1.5at.%. When the pump power is 180W, the laser output is 72 W, and the optical-optical conversion efficiency is as high as 40%.