Indispensable heat dissipation solutions for high-power lasers
In today's rapidly advancing industrial and technological fields, high-power lasers have become core tools in precision manufacturing, medical surgery, communication, and even aerospace. However, as laser power continues to increase, a key challenge emerges: thermal management. Excessively high temperatures can directly lead to a decline in laser efficiency, deterioration of beam quality, and even shorten the lifespan of core components. In addressing this global challenge, a seemingly ordinary yet crucial material is playing an irreplaceable role - molybdenum foil.
High-power lasers, especially fiber lasers and diode-pumped solid-state lasers, generate significant heat in their core pumping modules. These areas are key nodes for energy conversion but also the "hotspots" of temperature. If the heat cannot be rapidly and evenly conducted and dissipated, a "thermal lensing effect" will occur, causing the laser beam to distort and the focal point to drift, greatly reducing the precision of cutting or welding. Even more seriously, continuous high temperatures will accelerate the aging and degradation of optical components, resulting in irreversible damage.
Therefore, choosing an efficient thermal management material is of paramount importance for ensuring the stable, reliable and long-term operation of lasers.
Among numerous metallic materials, molybdenum foil has emerged as the ideal choice for heat sinks and thermal diffusion layers in high-power lasers due to its unique physical and chemical properties. Here are the four reasons why it stands out:
1. High thermal conductivity: Molybdenum strip has an exceptionally high thermal conductivity, which enables it to efficiently dissipate heat and maintain the optimal operating temperature of the laser.
Molybdenum foil has an excellent thermal conductivity of approximately 130-140 W/(m·K). This value is much higher than that of many common structural steels, meaning it can act like a "super highway" to quickly conduct away the heat generated in hotspots such as the pump module, preventing local overheating and ensuring that the core components of the laser operate within a safe temperature range.
This is a crucial advantage of molybdenum foil in laser applications. The interior of a laser typically contains various materials such as semiconductor chips, ceramic substrates, and glass. The coefficient of thermal expansion of molybdenum foil is very close to that of these materials. During the repeated power cycles (turn-on - operation - turn-off) that cause thermal expansion and contraction, molybdenum foil can deform in concert with adjacent components, significantly reducing the risk of cracking, delamination, or connection failure due to thermal stress, and ensuring the structural integrity of the laser under harsh operating conditions.
The melting point of pure molybdenum is as high as 2622°C. Even in the form of thin molybdenum foil, it can maintain its shape and mechanical strength at temperatures of hundreds or even thousands of degrees Celsius without softening or creep. This outstanding high-temperature stability ensures that the heat sinks made of molybdenum foil remain reliable throughout the long-term operation of lasers.
Modern technology can roll molybdenum strip extremely thin (tens of micrometers) while maintaining good flatness. This makes it flexible for application in the narrow spaces inside lasers, such as closely attached beneath laser diode bars or as a transition layer between the heat sink and the chip. Its excellent surface properties also facilitate the formation of a stable connection with other components through welding or bonding processes.
In the actual design of lasers, molybdenum foil usually plays a dual role as a "thermal diffusion layer" and a "stress buffer layer":
As a heat diffusion layer: It is directly placed beneath the heat-generating laser diode, rapidly spreading the concentrated point or line heat source over a larger area and then transferring it to the main heat sink (usually a water-cooled plate), thereby significantly enhancing the overall heat dissipation efficiency.
As a stress buffer layer: When two materials with significantly different coefficients of thermal expansion (such as semiconductors and copper heat sinks) need to be connected, placing a molybdenum foil between them can effectively absorb and buffer thermal stress, protecting the fragile semiconductor chips.
The molybdenum foil is in high demand in various parts of the world, such as: USA, Canada, Chile, Brazil, Argentina, Colombia, Germany, France, United Kingdom, Italy, Sweden, Austria, Netherlands, Belgium, Switzerland, Spain, Czech Republic, Poland.
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