Imaging Devices

Imaging can be achieved by any of two ways:

• Using the galvo-controlled mirrors: the laser beam is scanned over the sample following a predetermined pattern (laser scanning microscope). This is achieved by using galvo-controlled mirrors that scan the beam on the XY-plane. The z-axis change is achieved by mounting the objective on a piezo-stage, or using a stage with z-axis control
• Using a XYZ piezo-controlled stage; the beam is set at a position while the sample is moved over the beam (stage moving microscope).

Galvo-controlled Mirrors

Galvo-controlled scanning mirrors offer the best solution for fast imaging acquisition in a laser scanning microscope. The mirrors are housed in a unit that includes a rotating wheel mounting up to four dichroic mirrors and a descanning lens. Both single photon and multiphoton excitation can be utilized with the unit; for single photon excitation, light is brought to the unit by a single-mode fiber optics (3.5 µm diameter) with SMA connector.

XYZ Piezo-stage

The XYZ PZT is an actuated linear nanopositioning stage of exceptional resolution and stability. The 2.6" x 2.6" hole in the stage center is ideal for applications involving transmitted beams, multiple probes or inverted optics. With its large distance of travel and high stability, the PZT is ideal for the most challenging microscopy and positioning applications. The PZT comes complete with position sensitive detectors for closed loop operation.

Imaging Options: Which one should be used?
Two options are available for scanning. The user can select one of the two, or they can be implemented at the same time on the instrument.

One option consists in using galvo-controlled mirrors that move the laser beam across the sample (laser scanning technique). When using this option, the objective is mounted onto a piezo z-control. The galvo-controlled mirrors cover a surface area of about 200 µm in diameter with no optical distortions in the image. Image acquisition is fast (up to 4 µs dwell time per pixel). This option is utilized for fast imaging acquisition, fast scanning FCS, particle tracking and RICS acquisition.

Alternatively, an XYZ piezo-controlled stage can be utilized on Alba. When using this option, the laser beam stands still while the sample is moved. The piezo can scan the sample over an area of 100 x 100 x 100 µm or higher with no distortions in the imaging capabilities.