Automation of Measurements of A Stepper Motor-driven Optical Monochromator Using Python

Abstract

This project presents automatic control of measurements of a stepper motor-driven classic optical grating monochromator that is more than 50 years old. The automation of measurements was realized by the use of a stepper motor and the corresponding Python programming. The Python code, which follows the general outline of an earlier LabVIEW design, also includes a graphical user interface and an additional app for evaluation. The Python software is built in separate parts that work together. A central “state manager” (Finite State Machine, FSM) organizes and follows each step of the process. Other background parts handle specific tasks, such as moving the motor of the monochromator or collecting measurement data, while the main program keeps the user interface active and responsive. Besides allowing the user to manually change the wavelength step by step, the program can also perform automatic scans or carry out several scans in sequence from a list created by the user. This work enables the integration of high-quality historical optical instruments with modern experimental setups– for example, in high-resolution laser-induced f luorescence spectroscopy. The project is explained here, and the program code is shared publicly on GitHub as part of open science (Şeker et al. 2025). Test measurements using various lamps are presented.

Keywords

• Spectroscopy
• monochromator
• python
• GUI

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