Think back to your school days. Do you remember how your science teacher taught you about light by focusing on rainbows and refraction, and about electricity by connecting lightbulbs to batteries? Chances are, though, that she didn’t show you how each element works together as part of a system. In fact, this same issue frequently nags designers. Given the range of light, electricity and sensors – the sensor being the device that transforms photons to electrons thanks to the photoelectric effect – how do you choose a laser for different modes of operation? The prevailing understanding is that you can choose either a laser or a detector or an amplifier, but not all three at the same time, because each is an independent device. In truth, they’re highly interchangeable; a fact that many of us don’t recognize because we seldom see them operating in tandem. More than this, at any moment in time, you may have to choose which aspect of each phenomenon you need to focus on: if you’re looking at electricity, do you care more about electrons or the electromagnetic field? When it comes to light, do you need to concentrate on particles or waves? The real trick lies in considering the characteristics of all devices together. Look at the laser, for example, and weigh up how it influences the performance of your detector. Look at your detector, and how it influences the performance of the amplifiers that follow. Look at your optical system and how it affects the entire signal chain. This is critical, because unless you adopt a systems perspective, you may end up with a laser that’s super fast, yet which is hindered by a super slow detector, causing you to lose the value of that may have come about through a high signal. Or you could have a laser with low power, exacerbated by a detector with such low sensitivity that it perceives no signal. This is a problem space, because there are so many options and variables. And the only way to solve it is by finding a sweet spot that allows us to say, with some degree of certainty, that a specific combination of competencies will provide an assured level of performance, at a satisfactory price, that meets all the expectations of the client while addressing their need.