When the laser is working, when electrical energy or other forms of energy are converted into light energy, a large amount of heat will inevitably be generated. If this heat cannot be dissipated in a timely and effective manner, it will cause the temperature of the laser to rise, which will affect its output power, beam quality, wavelength stability, and may even damage the laser chip and internal optical components. Therefore, efficient and reliable heat dissipation is one of the key technologies to ensure stable laser performance and extend its service life. With the continuous improvement of laser power and the expansion of application fields, heat dissipation technology continues to develop and innovate. The following will introduce several main laser heat dissipation methods and their characteristics.
1960-1970
In the early days of laser development, output power was generally low (watt level and below). This stage mainly relies on natural convection and radiation heat dissipation, and the structure is simple and reliable. As the power of continuous wave (CW) gas lasers (such as CO₂ lasers) and early solid-state lasers increased to tens of watts, simple forced air cooling technology began to be applied. By adding a fan to the laser casing and using forced convection of air to remove heat, this is the first step in moving heat dissipation technology from passive to active.
1980-1990
The circulating water cooling system became the standard configuration of high-power lasers during this period. Research focuses on optimizing cold plate flow channel design, improving water quality (e.g., deionization) to prevent scaling and corrosion, and developing efficient external heat exchangers (e.g., cooling towers, dry coolers). At this stage, precision temperature control systems for compressor refrigeration have also begun to be used for semiconductor pump sources that are extremely sensitive to temperature and scientific research-grade lasers that require low noise.
2000s to present
The research frontier shifts to more efficient phase change cooling technology:
Spray cooling: By atomizing and spraying the coolant onto the surface of the heat source, using droplet impact and latent heat of phase change to remove a large amount of heat, the laboratory has achieved a heat dissipation capacity of more than 1000W/cm².
Microchannel boiling cooling: Guide the coolant to undergo a controllable phase change (boiling) in the microchannel, and use the latent heat of vaporization to greatly increase the heat dissipation limit.
Summary
To sum up, there are various heat dissipation methods for lasers, from simple natural cooling to complex and sophisticated compressor refrigeration and various new high-efficiency heat dissipation technologies, forming a complete technical system. In practical applications, comprehensive consideration and selection need to be made based on factors such as the laser's power level, structural form, performance requirements, usage environment, and cost budget. As laser technology develops towards higher power, higher brightness and smaller size, the development of more efficient, more compact and more reliable heat dissipation solutions will continue to be an important research topic in the field of laser technology and a key guarantee for promoting wider application of lasers in various industries.
