Scientists Bend Liquid with Power of Light

In the linked article, Prof. Wendy Zhang wouldn't disclose the identity or nature of the so called "liquid". Is it of some electromagnetic properties, to be influenced by this laser beam?

Then she goes into a description related to radiation pressure, which would make sense given the high velocity photons of laser, doing something to the liquid's surface tension (but what?) and so on.

The only practical implementation there, pops at the end of the article, as: "...controlling fluid flow through channels thinner than a human hair...", Which is good news frankly, provided it's there for the taking, not some extrapolation.

The apparent coherence of the liquid movement, may have to do with it's (chemical) molecular bond changing energy level or cohesive orientation.

So, Dear Wendy, What is this liquid?

Now we can interface fluidic amplifiers with photonics!

Provided it's not some wild speculation on their part

It makes sense that light energy could deflect water if it is composed of particles, and if photons have mass (momentum), but do they? Here it seems that they broke up the surface tension of the oil and water mixture.