# What is diffraction grating in spectroscopy?

## What is diffraction grating in spectroscopy?

A diffraction grating is an optical element, which separates (disperses) polychromatic light into its constituent wavelengths (colors). The polychromatic light incident on the grating is dispersed so that each wavelength is reflected from the grating at a slightly different angle.

What is the function of the diffraction grating in a spectrophotometer?

The diffraction grating of a spectrometer partially determines the optical resolution that can be achieved by the spectrometer and also determines the wavelength range. Selecting the correct grating is an important factor to optimize a spectrometer to obtain the best spectral results for the application.

How is diffraction grating spacing calculated?

This can be represented by the equation: d = 1/N where N = the number of groves per unit length (in this case, millimeters) From the diagram above, we see ‘d’ is the grating spacing, and ‘θ’ is the angle of diffraction.

### What are the types of grating?

Diffraction Gratings.

• Holographic Gratings.
• Sinusoidal Holographic Grating.
• Concave Gratings.
• Blazed Holographic Concave Gratings.
• Aberration Corrected (Flat Field Imaging) Concave Grating.
• Constant Deviation Monochromator Grating.
• Rowland Type Concave Grating.
• How does the diffraction grating in a spectrometer work?

The diffraction grating separates the wavelength components of the light by directing each wavelength into a unique output angle. The change in output angle as a function of wavelength, called the angular dispersion, plays an important role in determining the wavelength resolution of the spectrometer.

How are ruled gratings used in spectroscopic applications?

Two different types of gratings can be used for spectroscopic applications. A ruled grating consists of a material into which a large number of parallel grooves are etched and then coated with a highly reflective material such as gold.

#### How many lines of diffraction grating per centimeter?

It is possible to put a large number of scratches per centimeter on the material, e.g., the grating to be used has 6,000 lines/cm on it. The scratches are opaque but the areas between the scratches can transmit light.

How is the output angle of diffraction optimized?

Since the output angle β depends on the incident wavelength, the blaze angle optimizes the diffraction efficiency only in a range of wavelengths around the blaze wavelength λ B. Figure G-5 shows the center of the diffraction enveloped can be moved to coincide with one of the diffraction orders.