Photochemistry and Spectroscopy Department

Institute of Physical Chemistry, Polish Academy of Sciences

GRATING SPECTROGRAPH WITH A PHOTODIODE ARRAY

 

The spectrograph can be used for measurements from UV to near IR. The spectrum is registered by a photodiode array (25.6 x 2.4 mm). The distance between diodes in the photodiode array is 25 μm. A 1800 lines/mm diffraction grating (40 x 30 mm) is the dispersion element of the spectrograph. The focal length of the autocollimator mirror is 400 mm and the aperture ratio is adjustable within f/10 to f/14, depending on the grating angle. This angle can be changed continuously. The angle determines the spectral range imaged at the photodiode array and the spectrograph resolution. For instance, grating  angles of 10.4, 29.7, and 54.3 degrees result in the spectral ranges of 182 - 217, 534 -565, and 889 - 910 nm, respectively . The corresponing resolution is: 0.034, 0.030, and 0.020 nm.

http://ichf.edu.pl/zd-9/0099.jpg