Source: IPG Photonics

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Quasi-Continuous-Wave Operation in Lasers

Overview

Quasi-continuous-wave (quasi-CW) operation in lasers involves switching on the pump source for short intervals. This approach reduces thermal effects while maintaining the laser process close to a steady state, mimicking continuous-wave operation optically.

Benefits of Quasi-CW Operation

The duty cycle of quasi-CW operation is typically a few percent, significantly reducing heating and thermal effects such as thermal lensing and damage from overheating. This method allows for high output power in limited time intervals.

Comparison with Pulsed and Continuous-Wave Operation

Quasi-CW operation differs from pulsed operation, where an optical steady state is not achieved. It is commonly used with diode bars and stacks, with some devices designed specifically for this mode of operation to enhance brightness and beam quality.

Applications and Considerations

Diode bars, diode stacks, and certain doped-insulator solid-state lasers are often operated in quasi-CW mode. However, this approach may lead to additional lifetime issues due to higher optical peak intensities and frequent temperature changes.

Mode-Locked Lasers

Mode-locked operation of lasers, while not typically termed as quasi-CW, can resemble continuous operation in terms of gain saturation and average power calculation. This mode is characterized by a very high pulse repetition rate.

Conclusion

Quasi-continuous-wave operation offers a balance between continuous-wave and pulsed operation, providing a way to achieve high output power with reduced thermal effects. Understanding the nuances of different laser operation modes is essential for optimizing laser performance across various applications.

Source: MDPI
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