Here we show a confocal microscope system where a vertical-cavity surface-emitting laser (VCSEL) array is introduced for the parallel probing beams.A VCSEL array is a semiconductor laser device that emits circular beams vertically to the surface of the chip, which can directly be used as confocal laser microscope applications. The VCSEL device itself can be the parallel beam source of the confocal laser system, whereas in conventional Nipkow disc-based system, several lenses are required to form probing beams. Figure 1 shows the basic structure of VCSEL-based confocal microscope systems. Since there is typically no correlation between individual channels of VCSEL, there are no interferences among dense parallel beam arrays. Additionally, in the case of Nipkow disc system, the signal to noise ratio of the detected light is another problem: some of the light from the source laser reflects at the surface of the disc, which eventually could be detected by the sensor as noise. in the proposed system no such problem occurs as shown in Fig. 2(a). in addition, “all” optical beam from VCSEL is used as probing beam whereas most of the power is lost at the disc as compared in Fig. 2(b). in addition, pixel parallel illumination control is also achievable by controlling each channel of the VCSEL so that the dynamic range of the detected signal is maximized.
A Massively Parallel Imaging System Based on the Self-Mixing Effect in a Vertical-Cavity Surface-Emitting Laser Array
