Biophotonics

Using an array of on-chip optical tweezers in fluidic channels, photolithographically created directly on a Ga-As substrate, it is possible to optically tweeze cells in a device that is no larger than a few cubic mm. Light emission is generated by electrical injection into a GaAs/AlGaAs heterostructure, whose active region contains either quantum wells (emission 980 nm) or quantum dots (emission 1290 nm). High index cladding layers around the active region provide vertical optical confinement, whilst transverse confinement is achieved by a 3 µm-wide etched ridge waveguide, producing a zero-order beam. Microfluidic channels (typically 20-75 µm wide, 10 µm deep) are etched through an array of ridges to produce two banks of perfectly aligned counter-propagating dual-beam laser traps.

Key References

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