A designing method of aberration-reduced holographic gratings has been studied for Seya-Namioka monochromators. Aberrations such as astigmatism, coma and image curvature have been treated analytically without using numerical interation employed in a case of aberration balancing. Satisfying results have been given for both spherical and toroidal gratings.
A method of designing a mechanically ruled aberration-corrected concave grating and its mounting for a polychromator with a self-scanned sensor array is described. An aberration-corrected concave grating with flat detection field and astigmatism free focusing properties has been designed and fabricated for a wavelength-meter to measure the laser diode oscillation in the wavelength range of 720-820 nm. The grating has been designed so as to take also the linearity of wavelength and the channel number of a sensor array into account.