bi ltd

The Optical Table

Picture of Optical Table

The Optical Table is the base of the Modular System. The optical components are mounted on the two table arms, both of which can be rotated around a full circle. The table is designed to support masses of more than 3 kg at the end of each arm. This allows heavier components such as small monochromators to be mounted directly on the arm, eliminating the need for optical fiber systems that reduce the light intensity. A higher intensity throughput improves the signal-to-noise ratio and therefore results in a better signal quality of the measurement. The table has a very high rigidity, an important feature in imaging applications where any vibration or flexing of the arms can reduce the resolution of the image. Our new table is designed to achieve a resolution of at least 3Êµm per pixel when used with the Imaging Ellipsometer.

A free diameter of 140 mm in the center of the table makes it easier to mount large samples. Furthermore, the closest angle between both arms is as small as 20° for near-normal incidence measurements without the need to rearrange the components. This feature makes the table a convenient tool not only for ellipsometry, but other optical measurements such as transmission and reflectivity.

The angular position of the arms is computer controlled using optical encoders to ensure absolute position accuracy to 1/100°. Computer control is implemented through our universal Microcontroller interface.

Specifications

Resolution Computer controlled arm positioning to 1/100° (ablsolute).

Angle Limit Closest position between arms 20°.

Arm Movement Arms can be moved through 360°. This allows measurements at variable angles from both sides of the sample (e.g. for studies on liquids). With Imaging Ellipsometer, the imaging arm can be moved to normal incidence to use the instrument as a microscope.

Mechanical Stability Flexing of arms smaller than resolution limit when used with Imaging Ellipsometer at highest magnification (3 µm/pixel).

Arm drive Geared stepping motor/belt drive with optical encoders.

Computer Control Absolute position control through Beaglehole Instruments Modular System Microcontroller (compatible with any PC with one free serial port).