Lasers and Functionalized Materials

I want to ask

you about many things in this conversation, but I want to start with your lab.

How are you using lasers to discover new kinds of materials?

Yeah, that's a very interesting question.

So many people would know you can use high-power laser to cut and engrave materials, but many people might be surprised we actually can use lasers to create new functionalities from existing materials.

So this is really starting with we use a type of laser, so-called femtosecond lasers, so we can restructure a material surface and create a range of micro nanostructures.

And by controlling this material, surface structures, we can give ordinary materials some extraordinary properties.

For example, we can make a shiny piece of metal pitch black, or we can make a rapid surface, either attract water or repel water.

so-called hydrophilic or hydrophobic, and probably we'll discuss more in detail later on.

So, you know, with all this material surface processing technologies also enable a range of technologies, and very likely we are going to discuss more.

And so we like to think about laser as a tool for material discovery, rather than just use it for cutting and tooling.

And instead of searching for chemical compositions, we oftentimes use lasers to change the existing material and give them new functionalities.

Now, in the course of this program, I've talked to a few different researchers about different kinds of lasers, and maybe listeners have heard about laser tweezers to hold atoms and these kind of things.

Can you elaborate a little bit? What is a femtosecond laser?

Yeah, so femtosecond lasers will deliver short pulses that last at the femtosecond time scale.

So a femtosecond is a quadrillionth of a second.

So just give some perspective, a femtosecond to a second is what a second to about 30 million years.

So because of this extremely short time burst, so the femtosecond laser can pack enormous high peak power, peak intensity, even with very modest amount of energy input.

So many people think about femtosecond laser is a very high energy.

No, it's not a high energy.

It's actually very modest amount of energy.

You can still power it from your home outlet.

You know, I don't recommend people do that, but eventually a regular wall outlet and then the short pulse give this very high peak power.

So because this very high peak intensity can produce this surface micro nanostructures without creating heating up the surrounding material and create a melting of the material.

So this allows us the possibility to utilize femtosecond laser to create a surface structure and allow us to design the materials through laser processing.