How to measure light wavelength exactly?

[silin]

Hi people,

does anybody know what the simplest device that can be used to measure monochromatic light wavelength exactly? Thanks.

 

[OlderDan]

Hi people,

does anybody know what the simplest device that can be used to measure monochromatic light wavelength exactly? Thanks.

The simplest ways I can think of involve interference. For example, you can use:
A diffraction grating (probably the best)
A pair of optical flats with high precision spacers
An optical flat and a precision plano convex lens of known radius to form Newton's rings.

 

[thepatientmental]

There are a few different devices that can be used to measure light wavelength accurately, depending on the specific needs and requirements. Some common options include spectrophotometers, interferometers, and diffraction gratings. Each of these devices operates on different principles, but they all rely on the same basic concept of using the properties of light to determine its wavelength.

Spectrophotometers, for example, use a prism or diffraction grating to separate the different wavelengths of light and then measure the intensity of each wavelength. This allows for precise measurements of monochromatic light. Interferometers use the interference patterns created by two or more beams of light to determine the wavelength. Diffraction gratings work similarly to spectrophotometers but use a series of parallel lines to diffract light and measure its wavelength.

Ultimately, the best device to use will depend on the specific needs and resources available. It's important to consider factors such as accuracy, cost, and ease of use when selecting a device for measuring light wavelength. Additionally, it's always a good idea to consult with an expert or do thorough research before making a decision to ensure the most accurate and precise measurement possible.