Low-cost, High-performance Lasers: Novel Applications of Disk Laser Approaches

近年来在世界各地的实验室开发的尖端激光系统并不需要性能。例如，基于掺钛蓝宝石晶体的激光现在通常产生万亿分之一秒的脉冲：这是最短的人造事件。在这微小的零点几秒内，激光的功率相当于发电站的输出。这些和当今高性能激光器的其他极端规格使它们成为潜在的革命性工具。事实上，在整个科学和工程领域，这场革命已经开始，允许对非常小、非常快和非常复杂的东西进行详细研究。然而，潜力更大。今天的高性能激光还不是科学家口袋里的小刀；笨重而昂贵的巨人被锁在激光实验室里。激光工程的挑战是将这种性能和功率利用在一个实用的封装中，这样激光就可以提供给用户，而不是用户必须使用激光。这将引发第二次--而且可以说是更大的--应用革命。我们相信，使用激光材料的圆盘，而不是传统的棒，可以为普及高性能激光做出巨大贡献。造成这种情况的主要原因有两个。首先，激光材料的一些重要但有害的特性随长度的变化而变化；使用薄盘可以最大限度地减少这些问题。其次，精巧的激光器，如基于钛蓝宝石的激光器，通常由其他激光器泵浦；由于所需的性能水平，这些泵浦激光器的成本可能高达数万英镑。盘的使用降低了所需的泵浦光束的质量；因此，我们相信诸如激光二极管甚至LED这样的低成本设备可以与传统上需要高成本泵浦激光器的激光系统一起使用。由于这些设备是针对大众市场的，单位成本将很小，使它们成为理想的低成本泵源。即使有了这些改进，这种光源也缺乏泵浦传统精细激光器的功率和光束质量。然而，圆盘的几何形状消除了这些障碍，我们相信，这将使我们能够首次展示半导体激光泵浦钛蓝宝石和新一代LED泵浦激光器。这些都是潜在的颠覆性技术。更低成本、更紧凑的钛宝石激光器将把这种纯种激光系统的优势直接应用到应用中，而低成本的LED泵浦激光器将使需要精密激光器但损失或损坏不可避免的应用-如高风险海底或有毒物质传感-成为可能。

The cutting edge laser systems that have been developed in laboratories around the world in recent years do not want for performance. For example, lasers based on crystals of sapphire doped with titanium now routinely produce pulses of a few millionths of a billionth of a second: the shortest of man-made events. For that tiny fraction of a second, the power of the laser light is the equivalent the output of a power-station. These and other extreme specifications of today's high performance laser make them potentially revolutionary tools. Indeed, across science and engineering that revolution has started, allowing the very small, the very fast and the very complex to be studied in detail. The potential, however, is greater still. Today's high performance laser is not yet the penknife in the scientist's pocket; unwieldy and expensive, the titan is chained to the laser lab. The laser engineering challenge is to harness this performance and power in a practical package, such that the laser can go to the user rather than the user having to come to the laser. This will trigger a second - and arguably bigger - applications revolution. We believe that the use of a disk of laser material, rather than the conventional rod, can make a large contribution to civilising high-performance lasers. There are essentially two reasons for this. First, a number of important - but detrimental - properties of laser materials scale with length; these problems can be minimised by using thin disks. Second, finesse lasers, such as those based on titanium sapphire, are typically pumped by other lasers; these pump lasers can cost tens of thousands of pounds due to the performance levels required. The use of disks reduces the quality of the pump beam that is needed; thus, we believe lower cost devices such a laser diodes and even LEDs can be used with laser systems that have traditionally required high cost pump lasers.Serendipitously, the development of blue laser diodes for next generation DVD and high power light emitting diodes (LEDs) for solid-state lighting has led to a considerable improvement in performance of these light sources. As these devices are aimed at mass markets, the unit costs will be small, making them ideal low-cost pump sources. Even with these improvements, such light sources lack the power and the beam quality to pump conventional finesse lasers. However, disk geometries remove these hurdles enabling, we believe, the first demonstration of diode-laser pumping of Ti:sapphire and a new generation of LED pumped lasers. These are potentially disruptive technologies. Lower-cost, more compact Ti:sapphire lasers will take the benefits of this thoroughbred laser system directly to the application and low-cost LED pumped lasers will enable applications - like high-risk undersea or toxic substance sensing - that required finesse lasers but where loss or damage is inevitable.