SYLLABUS- PHYSICAL OPTICS & LASERS, UNIT-I
Interference of a light: The principle of superposition, two-slit interference, coherence
requirement for the sources, optical path retardations, lateral shift of fringes, Rayleigh
refractometer and other applications. Localised fringes; thin films, applications for
precision measurements for displacements.
Haidinger fringes: Fringes of equal inclination. Michelson interferometer, its
application for precision determination of wavelength, wavelength difference and the
width of spectral lines. Twymann Green interferometer and its uses. Iriensity distribution
in multiple beam interference, Tolansky fringes, Fabry-Perrot interferometer and etalon.
UNIT βII
Fresnel diffraction: Fresnel half-period zones, plates, straight edge, rectilinear
propagation.
Fraunhoffer diffraction: Diffraction at a slit, half-period zones, phasor diagram and
integral calculus methods, the intensity distribution, diffraction at a circular aperture and
a circular disc, resolution of images, Rayleigh criterion, resolving power of telescope and
microscopic systems, outline of phase contrast microscopy.
Diffraction gratings: Diffraction at N parallel slits, intensity distribution, plane
diffraction grating, reflection grating and blazed gratings. Concave grating and different
mountings. Resolving power of a grating and comparison with resolving powers of prism
and of a Fabry-Perrot etalon.
UNIT - III
Polarization, Double refraction in uniaxial crystals, Nicol prism, polaroids and
retardation plates, Babinetβs compensator. Analysis of polarised light. Optical activity
and Fresnelβs explanation, Half shade and Biquartz polarirneters.
Matrix representation of plane polarized waves, matrices for polarizers, retardation
plates and rotators, Application to simple systems.
UNIT-IV
Laser system: Purity of a special line, coherence length and coherence time, spatial
coherence of a source, Einsteinβs A and B coefficients, spontaneous and induced
emissions, conditions for laser action, population inversion.
Application of Lasers: Pulsed lasers and tunable lasers, spatial coherence and
directionality, estimates of beam intensity; temporal coherence and spectral energy
density.