Resolving power of grating

1. TOPIC:RESOLVING POWER OF
GRATING

2. contents
 What is diffraction grating?
 Resolving power
 Rayleigh’s criterion of resolution
 Resolving power of grating
 Mathematical expression for resolving power of grating.

3. RESOLVING POWER OF
GRATING

4. WHAT IS DIFFRACTION GRATING?
 Diffraction grating is an optical component with a periodic structure, which
splits and diffracts light into several beams travelling in different directions.
The emerging coloration is a form of structural coloration. The directions of
these beams depend on the spacing of the grating and the wavelength of the
light so that the grating acts as the dispersive element. Because of this,
gratings are commonly used in monochromators and spectrometers.

5. DIFFRACTION GRATING

6. RESOLVING POWER
 Resolving power is the ability of an imaging device to separate (i.e., to see
as distinct) points of an object that are located at a small angular distance or
it is the power of an optical instrument to separate far away objects, that are
close together, into individual images.

7. RAYLEIGH’S CRITERION OF
RESOLUTION
 According to Rayleigh criterion, two sources are resolvable by an optical
instrument when the central maximum in the diffraction pattern of one falls
over the first minimum in the diffraction of the other and vice versa.

8. RAYLEIGH CRITERION

9. RESOLVING POWER OF A
GRATING
 The capacity of an optical instrument to show separate images of very closely
placed two objects is called resolving power. The resolving power of a
diffraction grating is defined as its ability to form separate diffraction
maxima of two closely separated wave lengths.

10. EXPRESSION FOR RESOLVING POWER
λ
𝒅𝝀
=nN
or
𝝀
𝒅𝝀
=
𝑵 𝒆+𝒅 𝐬𝐢𝐧 Ө
𝝀

11. RESOLVING POWER

12. “THANK YOU”