Fiber Lasers for medical diagnostics and treatments: State of the art, challenges and future perspectives

摘要

Fiber laser is a fast growing yet quite young type of laser with huge potential in healthcare due to versatility and reliability. The talk discusses present and future for fiber lasers for medical applications and address future challenges and competitions with other sources. 1. INTRODUCTION Fiber lasers since their invention, over fifty years ago by E. Snitizer [1-3], have progressed at a different pace then solid-state lasers due to the constrain of drawing quality fibers. No much of a progress for nearly twenty years until the telecom boom, who boosted high-quality silica fiber for transmission, cheap and powerful fiber coupled 980-nm semiconductor lasers and Er-doped active fibers for amplifiers [4,5]. We can therefore state that among the various type of lasers, fiber lasers are, both as research and commercial tools, the youngest, yet the fastest growing due to several factors: reliability, efficiency, lower power consumption and overall cost, high power, high beam quality and flexibility (fiber non-linearity is easily exploited) [6-8]. As example, commercially available laser with 10 kW output power in single mode fibers were developed less than ten years ago [9]. Nowadays fiber laser are the tools boosting almost any type of industry and research activity from advanced manufacturing to sensing of pollutants, to life science and of course, to medical investigation and treatments. In this paper the author first discusses the state of the art in term of available output wavelength from fiber lasers and how they can satisfy requirements to operate in the first four optical biological windows [10]; second is briefly addressed, from a general point of view, where fiber lasers may offer a key advantage compared to most sophisticated solid-state laser systems or the cheaper compound semiconductor lasers; third indications on the extension of the available wavelength interval are given, focusing on Visible/UV and mid-infrared lasers (MIR) continuum generation and on the new class of mid-infrared fiber laser [11-15]. The paper does not aim to be exhaustive, nor to provide a summary of all contributions so far in the field, but to provide indications on the role fiber lasers may play in the future in the medical field and which new tools an end user may expect to find available in the next future.