While the paper's keywords list includes both microfluidics and photonics, nothing about the device is anything like an opto-fluidic logic gate. The laser is us

While the paper's keywords list includes both microfluidics and photonics, nothing about the device is anything like an opto-fluidic logic gate. The laser is used to measure properties of cells suspended in the fluid, with the output light signal being processed by conventional photonics.