A Simple Way to Find Wavelength of Light Accurately by Using Webcam

How can we measure the wavelength of a laser beam with simple, low-cost tools? In our recent work, "Measuring wavelength of laser beam using single slit diffraction: a simple but precise experiment using webcam and ImageJ software" we revisited the classic single-slit diffraction experiment but gave it a modern upgrade. Traditionally, this experiment involves photodiodes and optical benches, with painstaking manual measurements that are often error-prone. Instead, we used a paper screen, a regular webcam, and free software to make the process faster, easier, and more accurate.

The setup is simple: a laser beam passes through a narrow slit, producing a diffraction pattern on the screen. A webcam captures this pattern, and the free image-processing software ImageJ is used to measure the span of the central bright region. From this, we calculate the wavelength of the laser.

Using this method, we tested both a known red He–Ne laser and a green diode laser, achieving results very close to the rated values. This experiment not only improves precision but also shows how digital tools can transform physics labs into more engaging and accessible spaces.

Link our paper: https://iopscience.iop.org/article/10.1088/1361-6552/acfebf/meta




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