Optical Multiple-Particle Manipulation With a Rectangular-Shaped VCSEL

Optical manipulation of cells and particles is an efficient non-destructive technique for isolation and sorting in the field of biophotonics. For several years, vertical-cavity surfaceemitting lasers (VCSELs) have been investigated as light sources for particle manipulation inside microfluidic channels, where their small dimension and low power consumption enable direct integration with the channels. In such an integrated module, however, the simultaneous manipulation of multiple particles requires the use of densely packed VCSEL arrays with very small device pitch, making the fabrication process more expensive and complicated. We show efficient single as well as multiple polystyrene particle trapping and sorting inside polydimethylsiloxane (PDMS) microfluidic channels using one rectangularshaped top-emitting AlGaAs–GaAs VCSEL with an active aperture area of about 100 × 14μm. The VCSEL emission wavelength is around 850 nm, which is suitable for usage in biophotonics, as biological materials present little absorption in the near-infrared spectral range. Furthermore, the oblong-shaped VCSELs can potentially be integrated with PDMS microfluidic channels to form miniaturized optofluidic chips for ultra-compact particle handling and manipulation.