Final answer:
In spectrophotometry, a monochromator is used to allow a narrow band of wavelength to pass through, separating various wavelengths and enabling specific analysis. This sophisticated device is crucial for acquiring high-resolution images and has applications in various scientific fields.
Step-by-step explanation:
In spectrophotometry, the device that allows for a narrow band of wavelength to pass through is known as a monochromator. This device separates the various wavelengths of incoming light and ensures that only a beam with a specific wavelength is selected. Light first passes through a narrow slit and is collimated by a lens. It then travels through a prism or diffraction grating, where different wavelengths are bent by varying amounts and separated. A second lens focuses the spectrum onto a detector, such as a CCD, enabling a detailed analysis of the light.
Photographic and electronic detectors record the properties of light after it has been separated into its components. The monochromator's function ties closely with the concept of resolution, which is limited by diffraction, as described by the Rayleigh criterion. For optimal resolution, two images are just resolvable when the center of the diffraction pattern of one aligns with the first minimum of the other's pattern.
The application of monochromators extends beyond spectrophotometry into fields such as materials science, nanotechnology, and the biomedical field, where it provides high contrast and detailed information about chemical compositions, akin to molecular fingerprints.