Photonics Briefs – Martian Snow

One of my friends is amicably known as the “Martian weather girl,” as her job, with the Canadian Space Agency (CSA) is involved with plotting weather trends around the Phoenix lander, as well as analyzing the Martian soil for various salts.

Knowing someone like this gets you the knowledge, that apparently kept quiet by our government, that there is snow falling on Mars.

Now, to bring this to photonics, let’s look at the technique of LIDAR that was used to detect the falling atmospheric snow. Unfortunately the snow vaporizes before it reaches the ground, so there won’t be any snow-Martians.

LIDAR stands for “LIght Detection And Ranging” and relies on firing laser pulses into the sky and looking for bits that are reflected back by debris in the atmosphere. It’s analogous to when you shine a laser or flashlight into the fog and some of it gets scattered back at you.

The principle is fairly simple, and the only difficulty lies in collecting the scattered laser pulse. Luckily, signal-to-noise is greatly improved with the use of coherent laser pulses, so you at least know when you are seeing something.

That’s all for this week.

Photonics Briefs resumed

Sorry for the haitus last week, a cold and a shitstorm of activity kept me from posting. This week I want to focus on a photonic technology: namely, laser cutting.

Industrial laser cutters are typically made from CO2 or solid state Nd:YAG lasers, which are among the highest (continuous) output power lasers that are commercially available. Laser output powers are routinely up to 2 kW continuous. By focusing the laser onto the material meant to be cut. The intense electric field essentially turns solid material to plasma – or ionized gases. This means that lasers can cut materials that are traditionally extremely difficult to cut. The laser is typically controlled by a computer so the precision of laser cutting is typically higher than traditional means. And finally, since light does the cutting, there is no blade to be replaced.

In recent years the ability has been developed to employ laser cutters for very fine projects. Laser micromachining refers to the process of using lasers to etch devices on the micron scale. This opens the field for mass production of microfluidics (pictured), ink jet printer components, x-ray apertures, ruby-based orifices, and leak testing components.

Laser cutting is still a rather expensive technology, but don’t be surprised if in a decade or so your children’s high school shop class has a laser in it.

Photonics Briefs I

As a desire to make a new regular feature on this site, I’m launching the first Photonics Briefs, featuring new articles, research, and news on the field of photonics. For the first couple issues most of my news will likely come from Nature Photonics, although in the future I’ll try to look around a bit more. So hopefully every Sunday from now on you should be able to see a new edition of Photonics Briefs.
Continue reading Photonics Briefs I