A system with electronically tunable multi-focal laser control for high-throughput volumetric material processing

Background

Laser micromachining is a critical technology in modern manufacturing, enabling precise marking, scribing, and dicing of materials such as glass, semiconductors, and other substrates. This process is foundational for the production of microelectronic devices, optical components, and advanced data storage solutions. As the demand for miniaturized and complex devices grows, there is an increasing need for higher throughput, greater flexibility, and more precise control in laser-based material processing. Traditional approaches, which typically rely on a single laser focal spot, are often limited in their ability to efficiently process multiple regions or depths within a material, leading to bottlenecks in production speed and versatility.

Current multi-focal laser processing methods, such as those using Fresnel zone plates, spatial light modulators (SLMs), or liquid crystal (LC) lenses, present significant drawbacks. These technologies often require fixed optical patterns, which lack adaptability and limit the ability to dynamically adjust focal positions during operation. Additionally, their response rates are relatively slow, making them incompatible with the high repetition rates of modern ultrafast lasers and reducing overall throughput. Mechanical movement of optics or samples to achieve multi-depth processing further introduces complexity, increases the risk of misalignment, and slows down the manufacturing process. As a result, existing solutions struggle to meet the evolving demands for rapid, flexible, and high-quality laser micromachining in advanced manufacturing environments.

Technology

This technology is a high-throughput laser material processing system that integrates an ultrafast, tunable acoustic gradient (TAG) lens with a pulsed femtosecond laser to enable multi-focal marking, dicing, and scribing. By electronically oscillating the TAG lens at high frequencies, the system dynamically shifts the axial focal position of the laser, creating multiple, precisely controlled focal spots at different depths within a substrate during a single lateral scan. The system can operate in two modes: a synchronized mode, where laser pulses are triggered at specific phases of the lens oscillation for targeted multi-depth processing, and an asynchronized mode for continuous depth scanning. All focal patterns, oscillation amplitudes, and frequencies are controlled electronically via RF signal parameters, eliminating the need for mechanical movement of the optics or the sample. This enables simultaneous processing of multiple surfaces or intra-volumetric regions, with applications demonstrated in intra-volumetric modification of glass and dual-surface machining of transparent slides.

This solution is differentiated by its dynamic, electronically controlled multi-focal capability, which overcomes the limitations of traditional single-focal or fixed-pattern multi-focal laser systems. Unlike prior approaches using Fresnel zone plates, spatial light modulators, or liquid crystal lenses—which are constrained by slow response rates, fixed focal patterns, and system complexity—the TAG lens system offers ultrafast, real-time tunability of focal positions at rates compatible with MHz pulsed lasers. This allows for pulse-by-pulse adaptation of focal patterns, supporting complex, user-defined processing tasks and accommodating substrates with varying thickness or topography. The ability to simultaneously scribe or modify multiple depths or surfaces in a single scan significantly increases throughput and processing efficiency, while also improving quality—such as producing cleaner breaks in glass with fewer cracks. The system’s flexibility, speed, and electronic control make it a powerful tool for advanced manufacturing, microfabrication, and volumetric data storage applications.

Benefits

• Enables simultaneous multi-focal laser processing at different depths without mechanical movement, increasing throughput and efficiency.
• Provides dynamic, ultrafast, and tunable control of focal positions via a TAG lens, allowing flexible and customizable focal patterns.
• Supports both synchronized and asynchronized operation modes for precise or continuous depth scanning.
• Allows dual-surface laser machining in a single scan, improving processing quality and reducing cracks compared to single-focal methods.
• Compatible with high-repetition-rate femtosecond lasers, facilitating high-speed manufacturing applications.
• Reduces system complexity by electronically controlling focal spots, avoiding fixed-pattern or slow-response beam shaping optics.
• Enables intra-volumetric modifications and multi-dimensional data storage within transparent materials like glass.

Applications

• Simultaneous dual-surface glass scribing
• High-throughput wafer dicing
• Volumetric data storage in glass
• Parallel laser marking on substrates

Additional info

This system utilizes an ultrafast, tunable acoustic gradient (TAG) lens and pulsed laser for high-speed multi-focal processing. By oscillating axial focal positions at radio frequencies, it generates multiple focal spots at varying depths during a single lateral scan. Electronic RF control enables synchronized or asynchronized modes, facilitating simultaneous intra-volumetric modification or dual-surface machining. This eliminates mechanical optical adjustments, significantly increasing throughput for marking, dicing, and scribing.