At present, the space optical transmission is widely used in these new ultrafast laser applications where the pulse width is several picoseconds and the pulse energy meets the material processing requirements. These lens-based systems require tedious fine-tuning (especially long-haul transmission) and are subject to dust and particle contamination. In the entire optical path, a large number of optical components become a potential source of beam quality loss. In addition, this type of processing equipment generally requires a sturdy workbench of stable abutment structure, the laser must be as close as possible to the processing position, in the overall system design which means the need to spend a lot of cost and experience.
The lack of a standard beam-transfer solution results in a wide range of system design options, which greatly hinders ultra-fast red laser pointer from reaching a wider range of industrial applications. Replacement of the laser light source or other components requires the re-adjustment and calibration of the entire system, which ultimately undoubtedly increases the cost. Fiber-based beam transmission system can not be achieved at present, mainly due to the traditional fiber is not suitable for transmission of ultra-fast laser. Self-focusing, stimulated Brillouin scattering and Raman scattering are the main factors that limit the pulse width and the damage threshold. And other non-linear effects, will easily damage the fiber material or pulse waveform. As a conclusion, ultrafast pulses for industrial applications can not be transmitted through conventional glass fibers.
Microstructured hollow-core fibers (MHCFs, see Figure 2) support the transmission of light in a hollow core, such as an inflation or vacuum, which allows it to transmit very high power and completely eliminate Nonlinear effect. This fiber from the photonic crystal fiber (photonic crystal fibers) evolved, the earliest from the University of Bath (Bath University) Russell, Knight and Birks jointly developed. Since then, a variety of different types of micro-nano-structured fiber has been developed and proved its ability to transmit high-power ultra-fast strongest laser pointer potential. Such fibers have a core size similar to single-mode step-index fibers, and the core constraining the light behaves like an irregular crystal. But the difference is that its core length can be greatly extended, and bear a higher damage threshold. 99% of the laser light is conducted in its hollow core and the allowable pulse energy level is increased to the mJ level, well above the energy levels required for many materials processing.
With the proper integration of these fibers into an industrial beam transmission system, ultra-fast laser pulses of several hundred watts (multi-100W) and several hundred micro-joules (multi-100μJ) can be reliably guaranteed with perfect beam quality transmission. This beam transfer system allows the laser source and the specific application to be separated, the laser energy can be distributed to different workstations, and even flexible robot system has become a reality, these are undoubtedly greatly enhanced the possibility of industrial applications. Hollow-core fiber is very suitable for femtosecond pulse width because of its extremely low dispersion characteristics. An attenuation value of 30 to 70 dB / km or 1% per meter is achievable in the 900-1100 nm spectral range.
Improve the green laser pointer transmission efficiency, and improve the optical output of the beam quality. Because the focus after the spot is very small, the calibration range of only a few microns, the whole system of mechanical positioning and stability are made of high requirements. According to the different laser sources, the divergence angle of the optical system is close to the diffraction limit, and the focal position is the Gaussian energy distribution. But in any case, to meet such a mechanical stability and image quality requirements, from the current high-power continuous laser coupling technology, are already very mature.
The internal optical fiber itself is well protected, and the outer, solid casing can withstand the millions of bending of industrial robots or gantry mechanisms. The mechanical stress is reduced to a minimum, even in a roughing environment that is full of particles. Dust and moisture are not allowed to enter the fiber inside, otherwise it will reduce the performance and even damage to the optical fiber.
In the end of the cable connector has a protective glass to ensure that the internal sealing, it is a certain distance from the fiber-optic distance, to avoid the pulse energy to destroy its coating or material. The enclosed cavity of the cable can be filled with clean air or any other gas, with a certain positive pressure or a complete evacuation. The clamping members of the fiber 30mw laser pointeritself provide good thermal contact, and the optional water cooling feature provides efficient heat dissipation at high power levels. Precise fiber end-face calibration takes into account the error generated when replacing the fiber optic cable, in the replacement of the same cable almost no need to fine-tune the output focus again.
A new flange interface provides extremely high mechanical repeatability and fast connection. At the same time, O-ring provides an effective security protection to ensure that the general industrial manufacturing environment. In addition, the optical cable can have the same high-power continuous fiber optic cable with the same security features, protective casing can guarantee that when the internal fiber breakage will not have any buy laser pointer leakage. Fiber-optic breaks, interface connections, and coupling status monitoring are also available, according to industry standards.
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