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Applications and advantages of high-power ultrafast lasers
High-power ultrafast lasers have diverse applications due to their short pulse durations and high peak powers. Ultrafast lasers are used in materials processing, medical fiber lasers, microscopy, and more. These fiber lasers offer high power, but the technology is sensitive to effects like thermal lensing.
Thermal lensing in ultrafast lasers
Thermal lensing occurs in ultrafast laser gain media, especially at higher power levels. It significantly limits beam quality and output power. Thermal lensing reduces ultrafast laser performance and can disrupt mode-locking and pulse generation. In high-power systems, it can cause system failure and introduce astigmatism in the laser cavity. Ultrafast lasers operate in continuous-wave (CW) mode for cavity alignment, then switch to pulsed mode for use. Thermal lensing can interfere with this operation.
Methods to minimize thermal lensing
If pulsed beams are affected, ultrafast lasers become ineffective. However, several strategies can manipulate the thermal properties of gain media to prevent thermal lensing. One approach is using proper dispersive mirror coatings. Highly dispersive intracavity mirrors help minimize thermal lensing effects.
These advancements allow the production of high-power ultrafast lasers with intracavity optics that minimize thermal effects. The technology stabilizes beam quality and pulse compression while reducing harmful thermal effects.
Development of ultrafast mirrors
Highly dispersive ultrafast mirrors have been developed to maintain reflectivity and pulse compression while minimizing thermal effects, achieved through precise coating techniques. Some ultrafast laser systems do not need this technology, as thermal lensing is not significant in low-average-power lasers or systems without a solid-state cavity. However, high-power solid-state ultrafast lasers benefit greatly from thermal-lensing reduction.