Laser replacement for optical instrumentation and optical fibre sensor research

我们使用高功率脉冲激光进行一系列光学仪器项目。这种激光在红外线(1.06微米)、绿色(532 Nm)和紫外线(240-266 nm)波长下发出的光脉冲仅持续10纳秒，肉眼看不见，同样肉眼看不到。我们使用激光在光纤的纤芯上制作具有高度波长选择性的反射镜。这些传感器被用来检测纤维浸入的材料的应变、温度和折射率。我们还使用激光形成激光光片，由数码相机成像。通过将粒子放入空气中，激光被散射，我们可以利用多普勒原理测量速度；光学中的效果与声学中的相同，即散射光的频率随粒子的速度(速度和方向)而变化。这种非接触的速度测量方法在风洞测试F1赛车和飞机的空气动力学性能时非常重要，以使它们能够更快地行驶，但使用更少的燃料，并且在飞机噪音较小的情况下。

We use a high power pulsed laser for a range of optical instrumentation programmes. The laser emits pulses of light that last for only 10 nanoseconds at wavelengths in the infrared (1.06 microns),invisible to the eye, green (532nm), very visible, and the ultraviolet(240-266nm), again invisible to the eye. We use the laser to make highly wavelength selective mirrrors in the core of optical fibre. These are used to sense strain, temperature and refractive index of materials in which the fibre is immersed. We also use the laser to form laser light sheets which are imaged by digital cameras. By putting particles into the air the laser light is scattered and we can measure the velocity using the Doppler principle; the same effect in optics as in acoustics, i.e., the frequency of the scattered light changes depending on the velocity (speed and direction) of the particles. This non-contact way of measuring velocity is very important in wind tunnel testing of the aerodynamic performance of F1 cars and aircraft to allow them to travel faster but using less fuel, and in the case of aircraft with less noise.