Recently Thorlabs developed a new Video-Rate Laser Scanning Microscope System (VCM100) which offers real-time confocal imaging in a customizable open platform. The fiber coupled design of this system ensures a nearly Gaussian input beam by spatially filtering the light from a laser diode. In addition, two single mode fibers are used to deliver the illuminating light, as well as collect the back-scattered signal, replacing the pinhole that is used in traditional confocal systems by rejecting the out-of-focus light to create a true confocal image.
Rapid scanning in the VCM100 allows video-rate image collection with the high resolution of standard confocal systems, making this system ideal for real-time observations of biological processes, in-line production monitoring, and drug screening. The scattering mode yields best results for opaque and highly reflective materials, making it useful for material science and microelectronic applications, while the fluorescent mode provides excellent optical sectioning of fluorescent biological samples. This system is highly reconfigurable for other applications such as multiphoton fluorescence excitation or second harmonic generation imaging. The examples shown here represent the two standard setups: scattering and fluorescence.
The figure below shows a schematic of the VCM100 in scattering mode. In the standard backscattering configuration, a single mode fiber is used to couple a laser diode into the microscope head which is directed towards the scanning mirrors using a beamsplitter.
The combination of the resonant scanner and galvo scanner is used to raster scan the beam across the sample. The light is then focused onto the sample using an infinity corrected microscope objective, and the resulting backscattered light is collected back through this same objective. This backscattered signal is directed to the fiber coupled high-speed photodetector via the beamsplitter, as shown in the figure below. Sample data images are shown in the Microelectronics Application link to the left.
Figure 1:Figure 1. Schematic of VCM100 in Scattering Configuration
The VCM100 is easily changed from scattering to fluorescence mode by changing fibers and beamsplitters, adding dichroics or changing detectors. The user can easily reconfigure this confocal scan head for custom applications, such as confocal fluorescence microscopy or multiphoton excitation microscopy. A sample schematic for a standard single color laser scanning confocal fluorescence microscope is shown in the figure below. Sample data and applications including movies may be accessed via the links to the left.
Figure 2: Schematic of VCM100 in Confocal Fluorescence Configuration