As ultrafast lasers have evolved from extremely environmentally sensitive behemoths to compact, highly reliable laser sources suitable for integration into industrial applications, their applications have become more widespread, from the medical field to commercial electronics manufacturing.
In order to better utilize ultrafast lasers, it is critical to understand the recommendations for operating ultrafast lasers, including how to select the best optics, introduce dispersion and time aberrations, and when pulse compression should be considered for an application.
When selecting optics, the technical challenges associated with ultrafast lasers can make the choice difficult. The required spectral coverage, laser damage threshold (LDT) and dispersion specifications may be unfamiliar to users accustomed to continuous wave (CW) or longer pulse lasers.
The ultra-short pulse widths and very high peak powers of ultrafast lasers provide advantageous conditions for a variety of applications.
Spectroscopy applications. Since the introduction of ultrafast lasers, their use in spectroscopy has become ubiquitous. Reducing the pulse duration to the femtosecond order of magnitude makes it possible to observe dynamic processes in all types of physics, chemistry, and biology. The advent of ultrafast lasers has provided avenues for the detection of atomic motions and deepened our understanding of a number of fundamental processes, including molecular vibrations, dissociation, and energy transfer from photosynthetic proteins.
Bioimaging. The extremely high peak power of ultrafast lasers generates nonlinear processes that can improve the resolution of biological imaging, such as multiphoton microimaging. In order to generate a nonlinear signal from a biological medium or a fluorescent target, two photons need to overlap in space and time. Single-photon processes are highly susceptible to background noise, and nonlinear mechanisms can greatly reduce the background noise and thus improve imaging resolution.
Laser material processing. Ultrafast lasers have revolutionized laser micromachining and materials processing due to their ultra-short pulse durations. The duration of the ultrafast laser pulse itself is shorter than the time it takes for heat to diffuse into the material lattice. Compared to nanosecond pulsed lasers, this means that ultrafast lasers produce a much smaller heat-affected zone, allowing for lower kerf losses and more precise processing. In the medical field, the high precision of ultrafast laser cutting reduces damage to surrounding tissue and enhances the patient experience.
