Tunable Femtosecond Laser System

FDA/CDRH reviews and regulates safety and efficacy of medical diagnostics and therapeutics devices and marketed products involving non-ionizing coherent (laser) and noncoherent broadband optical radiation sources. However, in many cases of new technologies and products, we face major challenges of lacking standard test methods, protocols and tools for safety and efficacy evaluation of emerging laser radiation products. Development of novel femtosecond laser (FSL) technologies and products is an emerging field with significant public health impact on various biomedical areas including ophthalmology, dentistry, neurosurgery, cancer diagnostics and therapeutics, and nanotechnology.In the area of biomedical imaging, OSEL’s DBP uses of FSLs has led to several advanced imaging techniques including two-photon microscopy. Although the two-photon microscopy provides significant benefits of high-resolution, 3D and deep imaging of cells and tissue, FSLs also introduce novel safety concerns

requiring innovative consensus standard methodologies for maximum permissible exposure (MPE) safety evaluation of permissible laser emissions employed in FSL imaging techniques. Furthermore, the applications of FSL technologies have been broadly expanded to new therapeutic areas such as ophthalmic cataract surgery.However, due to FSL ability to provide unprecedently high levels of laser irradiances, FSLs have elicited previously unseen nonlinear optical effects at interactions of FSLs with tissue and cells. These effects lead to novel safety concerns related to phototoxic harmonic generation and multiphoton absorption, which are associated with potential photochemical, photothermal and photomechanical tissue and cell damage.The requested Tunable Femtosecond Laser System for the DBP is a critical FSL tool for developing and performing laser radiation safety evaluation of FDA regulated and emerging medical technology and products including FSL sources. This is a key equipment for accomplishing research goals and milestones associated with the research projects on laser radiation safety evaluation of the ongoing OSEL Research Program on Laser and Optical Radiation Safety (LORS) evaluation.These projects are focused on addressing safety concerns and unmet public health needs for quantitative evaluation of potential laser radiation hazards posed by femtosecond laser-tissue interactions in multiphoton imaging and therapeutic ultrashort laser-based technologies and medical products. The requested tunable FSL system will provide a tunable FSL spectral range including specific laser wavelengths required for safety evaluation in two-photon imaging and therapeutic applications. Moreover, the FSL system will provide also a high-power green laser source that can be used as a pumping source of an existing FSL system.In addressing the current major challenges and regulatory science gaps related to FSL radiation safety evaluation, the primary objective of this project as a part of the LORS program is focused on developing and implementing innovative consensus test methodologies and test protocols uncovered in current laser safety standards for MPE safety evaluation of permissible laser emissions employed in FSL multiphoton imaging techniques and therapeutic ultrashort laser based medical devices. The study will provide new independent data for performing standard laser radiation safety analysis and comprehensive assessment of safety and efficacy as well as for understanding the limitations and critical FSL and tissue parameters that affect the safety and efficacy of FSL based medical products.A critical test equipment for multifunctional safety evaluation of FSL radiation characteristics and accomplishing the research goals of the LORS project is the requested Tunable Femtosecond Laser System. It will provide a FSL source in a broadly tunable near-infrared spectral range including the specific laser wavelengths required for safety evaluation in two-photon imaging and therapeutic applications. In addition, the requested FSL system will provide also a high-power green laser source that can be used as a pumping laser source of an existing FSL system.The requested femtosecond laser system should provide a twofold benefit: (1) as a “primary system”, it should provide itself an independent femtosecond laser system of a tunable (760-840 nm) laser emission; (2) as a “secondary system”, the same primary laser system should be able to be used as a high-power green laser source for pumping  of an existing FSL system and, thus to provide a secondary tunable laser system in the range of 710-950 nm. Thus, this should be a single output laser beam system of either the laser beam as a direct output of the primary FSL system or the laser beam as an output of the existing secondary FSL system when the primary system is used as a pump laser source.