Carl Zeiss Microscopy Gmbh

Uwe Patz

Stefan Wilhelm

Dieter Huhse

Hans Schlüter

Alexander Liebhold

Erhardt Hülβe

A laser scanning microscope (LSM) having variable light intensity and a control method for the same. The light intensity of a laser beam in an LSM has been controlled to date with high accuracy, but also high costs by means of an acousto-optic component (AOM, AOTF). According to the invention, such a component for beam modulation is to be omitted, without reducing the exposure accuracy of the sample. In an LSM, a directly modulated laser diode () is used with an electric control () for direct modulation. Said laser diode () has a turn-on delay of the light intensity that is dependent on the amount of the control variable when subjected to an electric control variable. The control () is designed such that the fluctuation width (&#x394;&#x394;t) of the occurring turn-on delay (&#x394;t) is smaller than 1 &#x3bc;s, particularly smaller than 0.5 &#x3bc;s. Thus highly exact modulation without an acousto-optic component is possible. A quick direct modulation is achieved particularly by the following steps: a) identifying that an intensity to be achieved or achieved with the laser diode () falls below a lower threshold value or is below the lower threshold value, b) de-energizing the laser diode (), c) providing an electric intermediate current, d) identifying that the intensity to be achieved exceeds an upper threshold value, e) flowing the intermediate current through the laser diode (), and f) setting the diode current according to the intensity to be achieved.

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Gera, Germany

Uwe Patz