SA200-5A In Stock

The SA200-5A by ThorLabs is a highly sophisticated Fabry-Perot interferometer that is specifically designed for the examination of the spectral characteristics’ fine structures found in CW lasers. With a 1.5 GHz Free Spectral Range, this instrument is a must-have for anyone who needs to make highly accurate measurements of laser line shape.

The SA200-5A is equipped with an interferometer cavity with Invar and piezo stacks, which work together to create a nearly athermal cavity. This helps the device stay stable regardless of thermal changes due to the negative thermal coefficient of the piezo stacks. The SA200-5A features a spectrometer with a confocal cavity housing two high-reflectivity mirrors. Piezoelectric transducers can be used to vary the separation between mirrors, producing a narrow band-pass filter with an extraordinary level of precision. This enables incredibly precise measurements to be taken.

Knowing the Free Spectral Range of the SA200-5A allows the time-base of an oscilloscope to be calibrated, making it easy to facilitate quantitative measurements of a laser line shape. With a resolution of 7.5MHz, the fine structure resulting from multiple longitudinal modes of a laser line can be resolved. Additionally, the SA200-5A can be mounted via a Ø2" ring near the input end of the interferometer. For optimal performance, it is recommended to mount the device with a KS2 mount which will hold the device tightly and provide kinematic control necessary for proper alignment in the optical cavity. Setting up the SA200-5A is a breeze. Simply mount the device and center the beam in the iris opening. Once that is complete, the detector on the main body can be replaced and the unit can be used for measurements.

It's important to note that in order for the SA200-5A to achieve the specified resolution, the input beam diameter must not exceed the maximum diameter specification, even though the input aperture for the instrument is significantly larger than the specification. The apparent beam size should be approximately 4 mm, and it is recommended that a fold mirror be used to direct the beam into the interferometer. A lens with a focal length of 250 mm can be used, with the focus set roughly at the center of the housing, approximately 30 mm in from the flange. Additionally, the maximum voltage of the piezo is not to exceed 150V.