A Predictive Model for Picosecond Laser Reliability and Performance

Picosecond (ps) laser technology has become established, with widespread applications in industrial manufacturing, medicine, large-scale scientific research, and defence. However, the performance and reliability of all these systems have been limited by a fundamental problem: the absence of a reliable model for predicting when their optical components will fail.

While dependable models exist for nanosecond (ns) and femtosecond (fs) lasers, the ps regime has remained a challenging blind spot. This uncertainty has meant that manufacturers have needed to adopt conservative design cycles, which still creates operational risks for end-users.

At the recent SPIE Laser Damage Symposium in Rochester, Manx Precision Optics Managing Director, Dr Helmut Kessler, presented new research that directly addresses this “picosecond gap”.

“Our work introduces a new empirical model that provides a framework for moving from reactive testing to proactive, predictive design for optical components used in ps laser systems.”

Key Takeaways

• A new predictive model has been developed to solve the ‘picosecond gap’, a long-standing reliability problem related to optical coating damage in ps laser systems.
• This model helps avoid costly over-specification of high-power laser components and unexpected field failures by allowing for predictive, data-driven design.
• The commercial benefits include lower system costs, increased reliability, and faster R&D cycles for high-power lasers.

The True Cost of the ‘Picosecond Gap’ and Optics Failure

Without a reliable way to predict the laser-induced damage threshold (LIDT) of optics used in picosecond regimes, manufacturers and their customers have faced significant costs that were, until now, unavoidable.

Engineers are often forced to over-specify optical components. To avoid failure, designers must choose highly robust, and therefore expensive, optics to create a large safety margin. This is often done through a costly and time-consuming empirical cycle of procuring and testing sample optics until they are destroyed, a process that goes beyond standard LIDT testing. This process increases the bill-of-materials cost and extends development timelines.

A “lab-to-field” performance gap leads to unexpected failures. An optic can pass standardised certification tests in the lab but then fail prematurely in a customer’s system. The discrepancy between standard test and real world operating conditions, such as high repetition rates or the illumination of the optic’s entire surface, increases the risk of picosecond laser optics failure once the component is in use. An unexpected failure on a production line can halt manufacturing or interrupt critical research processes, ruining high-value products and creating severe financial consequences for the operator. This creates customer friction, leading to costly warranty claims and direct reputational damage.

Innovation is slowed by unknown performance limits. The fear of unpredictable failure can force manufacturers to deliberately “derate” their systems, running them at lower power levels than theoretically possible to ensure a buffer of safety. This means that most high-power ps lasers in operation are performing below their true potential. This untapped capability represents a major opportunity cost in terms of processing speed and throughput.

The Commercial Benefit: Predictive Modelling for High-Power Laser Components

Our research provides a quantitative framework to solve these challenges, offering significant commercial advantages for every stakeholder in the value chain:

• A reliable model enables the selection of optimised, cost-effective components. The new model allows an engineer to calculate a required LIDT value for a specific pulse duration using fundamental material properties. This transforms component specification from a qualitative request into a precise, quantitative science. It allows for the systematic optimisation of coating designs, leading to the selection of components that are both cost-effective and predictably reliable.
• Product reliability can be engineered, not just tested. By understanding and quantifying how system-level parameters affect the damage threshold, manufacturers can finally close the lab-to-field performance gap. Our work provides a tool to develop more realistic internal testing and simulation, mitigating the substantial business risk of in-field failures. As a result, this increases customer confidence and lowers the long-term cost of service and support.
• It accelerates research and development. The model will remove significant risk from the design process by allowing engineers to simulate performance and evaluate suppliers with quantitative data, which eliminates the inefficient ‘design-test-break’ cycle. This has the potential to enable system integrators to bring more advanced and reliable laser systems to market faster and with lower R&D investment. The model will allow engineers to confidently increase key performance metrics like power and repetition rate, in turn delivering tangible value to customers.

Successfully bridging the picosecond gap is a significant step for the industry. Our model provides a powerful new framework, which we recognise will now need more experimental data to fully refine it and establish it as an industry standard. This focus on predictable reliability is fundamental to enabling the next generation of multi-kilowatt-class ultrafast lasers and the applications they will enable.

Following the presentation at the SPIE Laser Damage Symposium, a full technical paper by Manx Precision Optics will be published in due course.